rs121907954

rs121907954, also known as c.805G>A, p.Gly269Ser and G269S, represents a variant in the HEXA gene on chromosome 15. Note that rs121907954 can also represent c.805G>C, p.Gly269Arg or G269R, which is also a variant in the HEXA gene. The rs121907954(A) allele is one of three most common mutations associated (when inherited recessively) with Tay-Sachs disease among Ashkenazi Jews. The rs121907954(C) allele, in dbSNP orientation, is also considered a pathogenic Tay-Sachs disease mutation according to ClinVar. 23andMe name for the the c.805G>A variant: i4000436 Exome Sequencing of Familial Bipolar Disorder. The minor allele of this SNP is one of 84 rare variants speculated to have an impact (positive or negative; see publication for specific SNP details) on risk for bipolar disorder. The analysis of many more patients is likely to be required to confirm or refute this association.

T;T

see discussion at Tay-Sachs disease

C;T

Unaffected in absence of a second HEXA gene mutation; see discussion at Tay-Sachs disease

G;G

This genotype should be extremely rare, representing a Tay-Sachs disease genotype (with two copies of an extremely rare mutation), but it is very commonly reported incorrectly in Ancestry raw data files and is therefore almost 100% certain to be a miscall if seen in your report (and, in reality, you have the completely common, normal genotype for this SNP).

C;G

Unaffected in absence of a second HEXA gene mutation; see discussion at Tay-Sachs disease.