rs137852283

A SNP in the F9 gene on chromosome X. Its most notable genotype is C;C: Hemophilia B (severity varies)

Gene
F9
Location
Chr X139,561,836 (GRCh38)
Highest magnitude
5.5Very important
Tested on
AncestryDNA

Genotypes

As shown in 23andMe and AncestryDNA files.

  1. C;CMost notableBadHemophilia B (severity varies)Very important · 5.5
  2. C;GBadCarrier of a Hemophilia B mutationImportant · 3.5
  3. G;GGoodcommon in clinvarTypical · 0.0
  4. G;TBadCarrier of a Hemophilia B mutationImportant · 3.5
  5. T;TBadHemophilia B (severity varies)Very important · 5.5

On SNPedia: (C;C), (C;G), (G;G), (G;T), (T;T). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.

Notes

From SNPedia

Show notes, about 420 words

Changes in this SNP indicate a mutation which occurs at an amino acid evolutionarily conserved in the factor IX gene of all known species. ncbi.nlm.nih.gov 1151 G>T Factor IX Padua Variant Results in Arg338Leu (also known as Arg384Leu). This is a gain of function, missense mutation results in hyperfunctional Factor IX protein, increasing risk for thromboembolism. X-linked thrombophilia with a mutant factor IX (factor IX Padua). A novel X-linked 1151G>T point mutation was found in a single Italian family in 2009. This variant resulted in hyperfunctional factor IX proteins associated with thrombophilia, specifically venous thromboembolism (VTE). While the level of this mutant factor IX protein in plasma was normal, the clotting activity in the proband was approximately eight times the normal level. This mutation was screened for in 200 controls and 200 patients with a documented VTE from the same geographic area as the proband, however none of these controls or patients had the R338L allele. Prevalence of Factor IX-R338L (Factor IX Padua) in a cohort of patients with venous thromboembolism and mild elevation of factor IX levels. No R338L mutations were found in this Brazilian study which evaluated 19 patients with documented VTE and 132 controls. Factor IX-R338L (Factor IX Padua) screening in a Dutch population of sibpairs with early onset venous thromboembolism. Evaluated 201 Dutch sibpairs with 2, 3 or 4 affected siblings with at least one objectively confirmed VTE (n= 438) without any Factor IX Padua mutations found. 1151 G>C Results in Arg338Pro (also known as Arg384Pro). This missense mutation results in Hereditary factor IX deficiency disease. Recurrent mutations in the factor IX gene: founder effect or repeat de novo events. Investigation of the German haemophilia B population and review of de novo mutations. Documented first case of this mutation in a hemizygous male with a published factor IX coagulant of 10%. The rates of G:C-->T:A and G:C-->C:G transversions at CpG dinucleotides in the human factor IX gene. Documented single case of a female heterozygous for this mutation, with 16% Factor IX activity.

C;G

X-linked recessive, so females are generally unaffected in the absence of a second F9 gene mutation, however some females may experience clotting issues.

G;T

X-linked recessive, so females are generally unaffected in the absence of a second F9 gene mutation, however some females may experience clotting issues.

Source and license

Adapted from rs137852283 on SNPedia, using a snapshot taken October 16, 2026. SNPedia content is shared under CC BY-NC-SA 3.0 US, and this page is shared under the same license.

SNPedia is a community-edited wiki. Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice. Magnitude is a community rating of how interesting a genotype is, not a risk score.