Importance of Investigating Somatic and Germline Mutations in Hemophilia A: A Preliminary Study from All India Institute of Medical Sciences, India

BackgroundHemophilia A is a common hereditary bleeding disorder caused mainly by mutations in the Factor VIII (FVIII) gene, which results in defective or absent FVIII protein. Most of the causative mutations arise from the germ cells, which leads to either heterozygous or hemizygous state for the mutation in the next generation. Germline or somatic mosaic may result due to a de novo mutation during early embryogenesis.MethodWe analyzed 14 families of Indian origin with Hemophilia A [sporadic and severe] for the presence of mosaic individuals by employing Allele Specific PCR, mutation enrichment experiment and sequencing.ResultNine families had point mutations, 3 families had small deletions or insertions, 2 families had splice site mutations. The origin of the de novo mutation was assigned to the patients' mother in 8 families. For 4 families it was assigned to the maternal grandmother and to the maternal grandfather in 2 families. In a single family somatic mosaic was detected.ConclusionThe presence of somatic mosaic in families with sporadic Hemophilia A in India may confound risk estimation during genetic counseling.