A novel SERPINC1 c.119G>A (p.Cys40Tyr) mutation with variable clinical expression in an Indian family.

Hereditary antithrombin (AT) deficiency due to mutations in SERPINC1 is known to be the most severe form of thrombophilia. We report three members in a family with hereditary AT deficiency with a novel mutation in exon 2 of SERPINC1, that is c.119 G>A (p.Cys40Tyr). Two brothers presented with acute pulmonary thromboembolism (PTE) at 18 and 21 years of age, whereas their 58-year-old father did not have any thrombotic episode till date. The in-silico prediction of the variant was found to be highly damaging by PolyPhen-2, SIFT and MutationTaster. Clinical exome sequencing did not show any strong coinherited thrombophilia genes, except SERPINE1 -844 G>A variant in homozygous state in the two affected brothers as compared to the father who was heterozygous for this variant. The additive effect of SERPINE1 variant in the clinical expression in two siblings cannot be ruled out, in the absence of any other known environmental triggering factors.