MTHFR and hyperinsulinemic hypoglycemia, familial, 4: These phenomena may be associated with a variety of congenital prothrombotic disorders (PDs), such as protein-C and protein-S deficiencies, AT III deficiencies (anti-phospholipid antibodies), Factor V Leiden (FVL), Prothrombin G20210A mutation, and C677T homozygous mutation of the MTHFR gene.