Today we’re going to look back at some of the health-related Spittoon highlights (a completely subjective list!) of 2009.

Hepatitis

Millions of people worldwide are chronically infected with some form of hepatitis virus, putting them at risk for cirrhosis and liver cancer.  In 2009 several studies identified genetic factors that influence susceptibility to hepatitis and response to treatment.

SNPwatch: Immune System Variations May Determine Susceptibility To Chronic Hepatitis B Infection

SNPwatch: Genetic Variation Predicts Hepatitis C Treatment Success

SNPwatch: More Evidence That Genetic Variations are Important for Hepatitis C Infection and Treatment

Melanoma

A study published in March offered insight into why melanoma, a rare but potentially deadly form of skin cancer, is more common in women under 40 than men in the same age group.

SNPwatch: Genetic Variation May Explain Why Young Women Are At Greater Risk For Melanoma Compared to Young Men

Alcohol Flush and Esophageal Cancer

Also in March, researchers issued a warning to physicians about the connection between “alcohol flush” and esophageal cancer.

Researchers Warn That Physicians Need To Ask About Alcohol “Flushing” To Reduce Esophageal Cancer Risk

Cystic Fibrosis Severity

Two studies in 2009 looked at how the severity of disease experienced by people with cystic fibrosis can be impacted by changes in genes other than CFTR.

SNPwatch: Genetic Variation That Reduces Immune Cell Activity May Lessen Severity of Lung Damage in Cystic Fibrosis Patients

SNPwatch: Genetic Flaw that Causes Rare Metabolic Condition May Also Increase Risk of Severe Liver Disease in Cystic Fibrosis

Glaucoma

In September a study found variants associated with glaucoma in people with African ancestry, a population that develops glaucoma at rates five times higher than Europeans and is also at much higher risk of blindness once glaucoma has set in.

SNPwatch: Common Variants May Influence Glaucoma Risk in Individuals of African Descent

Cisplatin-induced Hearing Loss

Just last month, researchers published results showing that certain genetic variants increase the risk for hearing loss in children after treatment with a common chemotherapy drug.

SNPwatch: Genetic Variations May Impact Risk of Hearing Loss in Children Receiving Common Chemotherapy Drug

Leprosy

The bacteria that causes leprosy is hard to study, but researchers have learned more about susceptibility to the disease by studying human genetics.

SNPwatch: Genetic Association Study of Leprosy Yields New Insights into an Ancient Disease

ShareThis

Our bones are amazing structures, capable of supporting tremendous force through complex motions. They do this day in and day out, year after year as we sit, stand, walk, run, lift, work, and play. But as the elderly among us know all too well, bones are not invincible and become more fragile as we age. As the natural, continuous cycle of bone turnover slows down and becomes unbalanced, bone is broken down faster than it is replaced — and important bone-strengthening minerals like calcium are lost.

Low bone mineral density (BMD) is one of the hallmarks of osteoporosis (literally “porous bones”), a disease that impacts nearly 45 million people in US and is responsible for more than one million fractures each year. Women develop osteoporosis much more frequently than men, especially after menopause. The burden on the health care system is significant and is expected to double over the next 10-15 years as the population ages.

Although it is natural to lose bone mass as we get older, genetic factors are known to play a large role in determining bone mass and the rate at which bone mineral density decreases. The relationship between genetics and BMD is complex, and association studies have implicated many different genes that may play a role. New research published this week in Nature Genetics continues the search for genetic factors and has identified more than a dozen SNPs associated with BMD in Europeans.

The team of researchers, led by Fernando Rivadeneira and Andre Uitterlinden of the Erasmus Medical Center in The Netherlands, used data from the Genetic Factors for Osteoporosis (GEFOS) Consortium containing lumbar spine BMD and femoral neck BMD measurements for almost 20,000 individuals. About half of the variants they identified replicated previously reported genetic associations with BMD, but the other half were new.

Some of the SNPs were associated with lower BMD while others were associated with higher BMD. For instance, individuals with one or more copies of the C allele at rs1366594 tended to have lower lumbar spine BMD than those without, and individuals with one or more copies of the C allele at rs2566755 tended to have higher lumbar and femoral neck BMD.

(23andMe customers can see their data for the SNPs currently covered by 23andMe’s service using the Browse Raw Data feature. See the table at the end of this post.)

The exact biological processes affected by these variants are still unclear, but increasing evidence points to several signaling pathways known to be important in bone biology.

One of these pathways is mediated by the “Wnt” family of proteins; Wnt signaling is important both for proper differentiation of cells responsible for breaking down bone and for the development of cartilage, required for new bone formation. rs87939, for instance, is near the gene that encodes β-catenin, an important node through which Wnt proteins influence cellular processes such as gene expression (this SNP is not on 23andMe’s platform but correlates perfectly with one that is, rs450615). Wnt proteins can also act through other channels potentially affected by additional SNPs identified by this study.

Another pathway implicated by the growing body of research is estrogen signaling. There is no doubt that the drop in estrogen following menopause in women leads to increased risk for osteoporosis, and hormone replacement therapy can have a protective effect. Not surprisingly, estrogen affects numerous biological processes – including bone maintenance – mainly through its role in gene expression. Variants in ESR1, the major estrogen receptor found in bone, have been associated with BMD and osteoporosis, though results are far from conclusive. Rivadeneira and colleagues confirmed the association of a SNP in ESR1, rs2504063, with lumbar spine BMD. Several other SNPs are also located in or near genes that may influence the regulation of bone development.

Osteoporosis is the most common bone disorder in developed countries. One in two women and one in four men over the age of 50 will experience a bone fracture due to the disease. Diets rich in calcium (especially before your mid-30s) and regular exercise can help combat bone loss. Meanwhile, the search carries on for clues that could lead to greater understanding of bone disease and potential avenues for treatment.

SNPs associated with bone mineral density (BMD):

* In some cases, 23andMe does not cover the original SNP, so a proxy SNP that correlates perfectly with the original in Europeans is reported instead.

SNPwatch gives you the latest news about research linking various traits and conditions to individual genetic variations. These studies are exciting because they offer a glimpse into how genetics may affect our bodies and health; but in most cases, more work is needed before this research can provide information of value to individuals. For that reason it is important to remember that like all information we provide, the studies we describe in SNPwatch are for research and educational purposes only. SNPwatch is not intended to be a substitute for professional medical advice; you should always seek the advice of your physician or other appropriate healthcare professional with any questions you may have regarding diagnosis, cure, treatment or prevention of any disease or other medical condition.

ShareThis

Millions of Americans suffer from the itchy, scaly skin brought on by psoriasis. In mild cases the condition is only a nuisance, but in the most severe cases it can be painful, disfiguring, and disabling.

Although the what of psoriasis is largely understood –immune cells mistakenly attack healthy skin cells, triggering further immune responses that lead to an overproduction of skin cells — – the why is not. Environmental factors, such as infections and injuries, may play a part, but twin studies have suggested that genetics has an even larger role.

Recent studies have started to unravel the genetics of psoriasis, showing that variations in several immune system genes can increase the odds of developing the disease. Now three studies, published online yesterday in the journal Nature Genetics, add to the list of variations associated with psoriasis and expand previous findings among Europeans to an Asian population.

Using data from more than 6,000 psoriasis patients with European ancestry and an equal number of unaffected controls, Rajan Nair and colleagues from the Collaborative Association Study of Psoriasis found seven genetic variations that were significantly associated with increased odds of developing psoriasis. All of these variations were in immune system-related genes, in keeping with previous research.

(Two of the variations identified by Nair et al are equivalent to SNPs already included in the 23andMe Health and Traits Clinical Report on psoriasis. Details of the four of the other five SNPs, and all others discussed here, are included in a table at the end of this post. Data on one SNP, near the TNIP1 gene, is not currently available from 23andMe.)

The second report, authored by Rafael de Cid and colleagues from several institutions in the United States and Europe, found a deletion of about 32,000 DNA bases that increases the odds of psoriasis. Their study used data from about 2,800 psoriasis patients and controls from the U.S., Spain, the Netherlands and Italy.

This deletion compromises two genes, LCE3C and LCE3B, which are part of a larger group of genes called the LCE gene cluster that are involved in the proper development of skin cells. de Cid et al speculate that other LCE genes are usually able to make up for the loss of LCE3C and LCE3B, but not perfectly. The result is skin that can become “leaky” due to injuries, allowing allergens and bacteria to penetrate the protective barrier of the skin. In someone with other risk factors for psoriasis, this could be enough to set off the inflammation characteristic of the disease.

(23andMe customers can use data for a SNP located near the deletion as a proxy for this variation.)

This week’s final Nature Genetics report on psoriasis comes from Xue-Jun Zhang and colleagues, who looked at SNPs in a large group of Han Chinese people (more than 5,000 patients and 6,500 controls) and a smaller group of Chinese Uygurs (539 patients and 824 controls). According to the authors this is the first study of its kind to examine genetic variations linked to psoriasis in the Chinese population.

Zhang et al. found three genetic variations associated with psoriasis in the Chinese population. Two of these – located in the HLA and IL23A genes – were replications of well-established associations in Europeans. The third association was in the LCE gene cluster, supporting the association in this same region found by de Cid in Europeans.

The results of all three studies may help scientists better understand psoriasis, but as Nair et al point out, they are only the beginning of a long road. Researchers will need to look more closely at the regions of the genome identified in these and other studies to find the true causes of the risk increases they have seen. The SNPs found so far are likely to only be signposts pointing the way. Further studies, using larger sample sizes and drawing together the findings of multiple research groups, will also be needed to uncover the many other genetic variations that likely contribute to psoriasis.

*”Effect” is the increase in odds compared to someone with two copies of the non-risk version of each SNP.

Europeans

Chinese

ShareThis

Our SNPwatch posts here at The Spittoon are one of our most exciting features. They give our customers the opportunity to connect their genetic data to the newest discoveries, often within just hours of a study’s publication.

Looking ahead to 2009, we can only begin to imagine the exciting discoveries that will be made in genetics. In the meantime, here are a few of our favorite SNPwatches from 2008:

SNPs That Affect Drug Response
We reported on several studies this year that showed the importance of genetic variations in determining how different people react to certain medications.

• A report in Nature Genetics showed that some women with a particular version of a SNP in the NQO1 are less likely to survive breast cancer after treatment with the commonly used chemotherapeutic epirubicin.
• A study by the SEARCH Collaborative Group found that a version of one SNP is associated with an increased risk for myopathy (muscle pain and/or weakness) in people taking cholesterol-lowering drugs called statins.
• Mayo clinic researchers found that the weight loss drug sibutramine (Meridia) is effective only in people with specific versions of three different genes.
• And just this month we brought you news of three studies that showed that a genetic variant known to affect the metabolism of the anti-clotting drug clopidogrel (Plavix) also affects heart attack patients’ risk of a second major cardiovascular event.

Shared SNPs
Sometimes multiple conditions strike the same person or run in families. Several studies published this year showed that shared genetic risk factors may be part of the reason why.

• Obesity is a known risk factor for many cancers. Researchers found that a variant of adiponectin, a hormone released by fat cells, can increase the risk of developing colorectal cancer.
• Other researchers found variants that affect the risk of developing both type 1 diabetes and celiac disease, two autoimmune diseases that tend to cluster together. One of these shared variants is also associated with HIV resistance.
• Finally, a report published this month in the Proceedings of the National Academy of Sciences showed that a single genetic variant can make a person prone to greater indulgence in both smoking and drinking.

SNPs Associated with Risk Factors for Disease
Several studies this year looked beyond disease itself and instead found associations between SNPs and traits known to be risk factors for disease.

• One study found an association between several SNPs and fasting plasma glucose, a measure of how well a person’s body can control blood sugar levels – a process that goes awry in diabetes.
• Another research group reported SNPs associated with glycated hemoglobin levels, a measure of long-term blood sugar control and another factor associated with the risk of developing diabetes.
• The findings of three papers published in Nature Genetics roughly doubled the number of SNPs associated with blood levels of cholesterol and triglycerides, important risk factors for cardiovascular disease.
• And finally, in a study that looked at behavior instead of metabolic markers, researchers found that a variant in the FTO gene known to increase the risk for obesity affects food choices in children, pushing them towards foods denser in calories.

ShareThis

Most children have mastered the complexities of spoken language by age six or seven,. But about 5% of otherwise healthy children struggle with either expressing themselves, understanding what others are saying or both, a disorder known as specific language impairment (SLI).

In a report published online yesterday by the New England Journal of Medicine, researchers from the Wellcome Trust Centre for Human Genetics at the University of Oxford present evidence that a gene called CNTNAP2 is involved in specific language impairment.

“It has long been suspected that inherited factors play an important role in childhood language disorders,” Simon Fisher, senior author of the study, said in a statement. “But this is the first time that we have been able to implicate variants of a specific gene in common forms of language impairment.”

Several previous studies have linked broad regions of DNA with SLI, but there has yet to be any consensus on the true genetic underpinnings of the disorder.

The researchers narrowed in on the role of CNTNAP2 in SLI because it interacts with FOXP2, another gene implicated in the development of language skills. Some people with rare speech disorders have mutations in FOXP2, but variations in this gene have not been associated with more typical forms of language impairment.

In a study of children from 184 families with at least one child affected by SLI, the researchers found that each G at rs17236239 decreased the score on a test that measures the ability to hear and repeat nonsense words like “brufid” and “contramponist” by 5.53 points on average. Previous studies have indicated that this test is a good indicator of SLI.

Each G also decreased a child’s score on the standardized Expressive Language Score, which measures the ability to communicate through spoken language, by an average 3.21 points. Scores can range from 46 to 141 for the nonsense word test, and 50 to 150 for the expressive language test. Most children in the general population get a score between 85 and 115 on both.

(23andMe customers can check their data for rs17236239 using the Browse Raw Data feature.)

Variants in the same region of CNTNAP2 as rs17236239 have also been linked to delayed speech in children with autism. Some experts suggest that the different components of autism-spectrum disorders, such as communication problems, impaired social interaction, and repetitive behaviors, could be due to different genetic influences. Fisher and colleagues suggest that alterations in CNTNAP2 could be a shared mechanism for pure SLI and language problems associated with autism.

The research team plans to investigate whether variants of CNTNAP2 are linked to natural variations in linguistic abilities in the general population. They also plan to investigate other genes that interact with FOXP2.

“Genes like CNTNAP2 and FOXP2 are giving us an exciting new molecular perspective on speech and language development, one of the most fascinating but mysterious aspects of being human,” said Fisher. “This work promises to shed light on how networks of genes help to build a language-ready brain.”

In an accompanying editorial in NEJM, Karin Stromswold, who was not associated with the research, said that the findings of the British study and others like it could someday help tease apart the genetic and environmental factors that affect language and language disorders. Stromswold questioned, however, why others studies of SLI have never implicated the DNA region where CNTNAP2 is found, even when the same group of children was studied.

ShareThis

Obesity affects about one out of three adults in the United States. And because obese people are at increased risk of high blood pressure, diabetes, cardiovascular disease and other health problems, many authorities consider it one of the most significant public health problems in the developed world.

Of course diet and exercise are important parts of maintaining a healthy weight, but some people need a little more help. Sibutramine (marketed by Abbott Laboratories as Meridia® in the U.S.) is a drug that creates a feeling of fullness, prevents the decline in metabolic rate usually associated with low calorie diets and causes weight loss, especially when combined with behavioral therapy.

But success with sibutramine is variable – for some people it just doesn’t work. New research, published in the October issue of Gastroenterology, shows that genetic differences might be to blame.

“Our results suggest the genetic make-up of patients could predispose their responsiveness to a drug. This could have important implications for the future of personalized molecular-based or individualized medicine,” said the study’s lead author Dr. Michael Camilleri in a statement.

(A video of Dr. Camilleri describing his research can be found at the end of this post.)

Using a sample of 158 overweight and obese people, researchers at the Mayo Clinic tested the effectiveness of sibutramine therapy compared to placebo over 12 weeks. All participants also received behavioral therapy.

The researchers found that weight and body mass index were significantly reduced in patients taking sibutramine compared to placebo, as was expected from previous research. But upon further inspection of the data, the researchers found that only people with certain versions of three different genes experienced significant weight loss.

People with at least one T at the SNP rs5443, in the GNβ3 gene, had success with sibutramine, losing about 13 pounds. People with at least one T at rs5443 and two Cs at rs1800544, in the α2A gene, lost even more weight – more than 17 pounds on average. The drug had no effect if a person had two Cs at rs5443.

The third genetic marker scientists investigated, known in the scientific literature as 5-HTTLPR, is a stretch of DNA that comes in a long and short form. Only people with one or two copies of the short version of this marker had significant weight loss with sibutramine. 23andMe does not currently give data for this type of variant.

“Genetic variations may help select obese patients who are more likely to experience improved outcome with this treatment. Since the different markers were present in almost 50 percent of patients, inclusion of screening for the genetic markers before prescribing the medication may even be cost-effective from a public health perspective,” Camilleri said.

ShareThis

Basal cell carcinoma is not only the most common form of skin cancer in the United States – it’s the most common cancer overall. Close to a million new cases are diagnosed each year. Luckily, this type of cancer is easily treated and unlikely to spread. It can, however, cause extensive damage to surrounding tissue and bone if it’s not removed.

The biggest risk factor for basal cell carcinoma (BCC), as well as several other types of skin cancer, is sun exposure. People with light skin, hair, and eyes – who have low levels of the protective skin pigment melanin – are at especially increased risk. It’s therefore not surprising that many of the genetic variants associated with skin cancer are also linked to fair pigmentation.

A new study, published online Sunday in Nature Genetics, has identified two SNPs on chromosome 1 that increase the risk of BCC, but are not linked to a person’s coloring.

After studying more than 2,000 people with BCC and close to 36,000 controls from Iceland and Eastern Europe, Stacey et al found that each A at rs7538876 and each G at rs801114 increased the odds of developing BCC 1.28 times over those with two Gs or two Ts, respectively.
(23andMe customers can check their data by clicking on the links above that lead to our Browse Raw Data feature)

The authors of the study estimate that about 1.6% of people with European ancestry have two copies of the riskier versions at both of these SNPs, and that these people have 2.98 times the odds of BCC compared to people who have no risky copies.

The researchers then looked at the DNA of people with two other types of skin cancer that, like BCC, are related to sun. But in about 400 people with squamous cell carcinoma and about 2,000 with cutaneous melanoma, they saw no association with the SNPs.

“One unifying theme may be that genes associated with fair pigmentation confer cross-risk of all three skin cancer types because of their roles in protection from the shared risk factor of UV light, whereas the more specifically associated variants may act through different pathways,” the authors write in their report.

To investigate this idea further, the researchers looked to see if the two new BCC-associated SNPs were related to pigmentation at all. In a sample of about 5,000 Icelandic people they found that neither SNP was linked to eye or hair color, nor were either of them linked to a propensity to freckle or sun sensitivity.

“Taken together, these data suggest that the [SNPs] act through pathways other than those related to UV-susceptible pigmentation traits,” the authors write.

ShareThis

Almost half of all men will eventually be affected by male pattern baldness. This form of hair loss, which begins above the temples, continues to form a characteristic “M” shape and sometimes progresses to complete baldness, has been shown to be related to certain hormones, such as testosterone, called androgens.

Genetics has long been known to play the dominant role in determining whether a man would go bald, but it wasn’t until 2005 that a specific gene was connected to male pattern baldness.

The gene, which encodes an androgen receptor (AR), is on the X chromosome. This means that men inherit only one copy of the gene, and that this copy always comes from their mothers. It’s possible that this is part of the reason behind the adage that male pattern baldness skips a generation.

(23andMe customers can find out more in the Research Report on Baldness.)

But the AR gene doesn’t completely explain the inheritance of male pattern baldness, suggesting that there are still genes to be found. New research, published online Sunday in Nature Genetics, provides evidence that one of these genes might be on chromosome 20.

Axel Hillmer and colleagues at the University of Bonn in Germany, who were involved in the research that first connected the AR gene and baldness, have now shown that the approximately 80% of Europeans with one or two Ts at rs2180439 have increased odds of male pattern baldness compared to the men with two Cs.

Just how much these odds are increased depended on how the researchers conducted their experiments. In one sample, 296 Germans who went bald before age 40 were compared to 347 male and female German controls, some of whom may have had some degree of balding. The researchers found that each T at rs2180439 increased the odds of male pattern baldness 1.82 times. But in another sample, 319 bald German men were compared with 234 German men who had made it past age 60 without going bald, and the authors found a 2.17 times increase in odds for each T.

Richards et al conducted an independent study of baldness in more than 2,700 men from Switzerland, England, Iceland and The Netherlands. They found a different SNP on chromosome 20 linked to male pattern baldness. Each A at rs1160312 increased the odds of baldness by 1.6 times over men with two Gs. 23andMe does not currently provide data for this SNP.

There is no obvious direct connection between the SNPs the two research groups found, but the fact that they independently linked chromosome 20 to male pattern baldness suggests that scientists may be zeroing in on another “baldness gene.” Finding this gene and the causative variation for baldness could have implications for research on several other common medical disorders which tend to be associated with baldness: coronary heart disease, hypertension and insulin resistance.

Discoveries about the genetics of male pattern baldness could also lead to new treatments, which according Richards et al is really big business. They cite financial disclosures from Merck that said global annual sales of an exisiting medical therapy for male-pattern baldness at upwards of $405 million.

“Clearly most men know if they are bald or not – but early prediction before hair loss starts may lead to some interesting therapies that are more effective than treating late stage hair loss,” said study author Tim Spector, of King’s College London, in a statement.

ShareThis

Age-related macular degeneration (AMD) is the most common cause of irreversible vision loss in the western world among people over 60. The two forms of the disease – wet and dry – both cause vision loss by destroying cells in the central portion of the retina.

In the last few years, progress in understanding AMD has been made thanks in part to the discovery of several common genetic variants, or SNPs, that together explain a large part of the risk for the disease. Several of these recently discovered AMD SNP associations have pointed to a role for the immune system in the disease.

A new study published online Monday in The Lancet yet again links the immune system to AMD. As is the case for several of the previously found SNPs, the variant found in this study is in a gene involved in the complement pathway, an arm of the immune system that facilitates the elimination of both pathogens and cellular debris.

Many years ago some researchers suspected that the complement system might be involved in AMD. Proteins from this pathway were found in drusen, the small crystalline deposits that build up in the eyes of people with AMD. But it was not until genetic studies started to show a link between AMD and complement genes that other scientists began to sit up and take notice.

In two separate samples — one British with 479 AMD patients and 479 controls, the other from the U.S. with 248 cases and 252 controls — Ennis et al found that the odds of developing AMD were reduced for every A T a person had at SNP rs2511989. Those with one A T had 0.68 times the odds of people with the GG CC genotype, and people with two As Ts had 0.44 times the odds.

(23andMe customers can check their data for rs2511989 using the Browse Raw Data feature. Note: The original post talked about As and Gs.  But our Browse Raw Data actually gives the data in terms of Ts and Cs.  Two different ways of looking at the same thing!  Sorry for the confusion!)

SNP rs2511989 is in the SERPING1 gene, which encodes a protein that regulates the complement pathway.

“Our findings add to the growing understanding of the genetics of age-related macular degeneration, which should ultimately lead to novel treatments for this common and devastating disease,” the authors write.

In an accompanying comment in The Lancet, Caroline Klaver and Arthur Bergen, two scientists not associated with the research, said the results of Ennis et al need to be replicated in large, independent samples before SERPING1 will be established as a true risk factor for AMD. They also suggest that the researchers may find other SNPs within the gene that are even more tightly linked to AMD.

ShareThis

John Henry “Doc” Holliday is rumored to have been born with a cleft lip and palate.

Beginning in the fourth week of gestation, the cells of a developing human fetus begin a complex program of rearrangements to form what will eventually become a child’s face.

In about one out of every 700 births this process goes awry. Genetic and environmental factors, acting alone or in concert, prevent the cells of the face from coming together properly, resulting in cleft lip and/or cleft palate. Though clefting can cause problems with feeding, ear infections and tooth development, surgery and other treatments can allow children to grow up to lead perfectly normal lives.

Although there are some rare genetic syndromes that cause cleft lip and/or palate, most cases of clefting are probably due to a combination of genetic factors that increase risk slightly and environmental triggers such as exposure to certain infections, some medications, alcohol and drug use, cigarette smoking, and certain vitamin deficiencies, especially during early pregnancy.

Fedik Rahimov and colleagues have now found the first common genetic variant, or SNP, strongly associated with cleft lip. Their results, published online Sunday in Nature Genetics, show that the common, non-inherited form of this condition is linked to a gene called IRF6 that was previously associated with a rare, dominantly inherited clefting disorder called Van der Woude syndrome.

Using 280 European families affected by cleft lip only, the researchers found that having one A at rs642961 increased the risk of this condition 1.91 times over the risk of those with two Gs at this SNP. That increase in risk rose to 2.29 times for people with two As.

Approximately 50% of people born with cleft lip also have a cleft palate. The link between rs642961 and cleft lip with cleft palate was not significant. Having cleft palate alone (no cleft lip) is rare, and there was no evidence that rs642961 was linked to this condition either.

(23andMe customers can check their data at a proxy SNP, rs861020, The version that increases risk of cleft is A for this SNP as well).

The authors note that the A version of rs642961 is least commonly found in Africans and most common in Native Americans, which mirrors the different levels of cleft lip and palate found in these populations. Because this research was conducted in Europeans, determining whether this SNP is associated with cleft lip in these populations will require further research.

ShareThis