Congenital TTP (cTTP), also referred to as Upshaw-Schulman syndrome (USS), is a very rare autosomal recessive disorder caused by biallelic homozygous or compound heterozygous variants within the ADAMTS13 gene, leading to severely decreased or absent proteolytic activity. This evidence concerns the gene ADAMTS13 and congenital thrombotic thrombocytopenic purpura.