A novel homozygous frameshift mutation in Exon 7 of the ADAMTS13 gene in a patient with congenital thrombotic thrombocytopenic purpura from India: a case report

BACKGROUNDThrombotic thrombocytopenia purpura (TTP) is a rare and life-threatening thrombotic microangiopathy characterized by thrombocytopenia and microangiopathic hemolytic anemia. It is caused by deficiency of ADAMTS13 metalloprotease, which cleaves ultra-large von Willebrand factor into smaller functional units. TTP may be congenital or acquired, and the congenital form is caused by inherited mutations in the ADAMTS13 gene, leading to deficiency of protein or reduced protein activity. CASE REPORTWe report a 5-year-old male patient who manifested with thrombocytopenia and microangiopathic hemolytic anemia at the age of 1 year. CONCLUSIONADAMTS13 activity in the patient was below 5%, and ADAMTS13 antibody was absent. Subsequent genetic analysis of the ADAMTS13 gene revealed a novel homozygous mutation (i.e., frameshift insertion mutation A237GfsX153 [c.708_709insG] in Exon 7 of ADAMTS13). Both parents were heterozygous for this mutation.