PCSK9 and progressive microcephaly-seizures-cortical blindness-developmental delay syndrome: The human diaphanous related formin 1; DIAPH1 (also known as DFNA1, DIA1), located on 5q31.3, which encodes homodimeric “Protein diaphanous homolog 1” belongs to the human formin family.8 This protein includes GBD/FH3 (DID), FH1, FH2 and DAD domains and is involved in actin polymerization and microtubule stability (Figure 4).8 Mutations in DIAPH1 are associated with “Deafness, autosomal dominant 1, with or without thrombocytopenia; DFNA1” (MIM: 124900) and “Seizures, cortical blindness, microcephaly syndrome; SCBMS” (MIM: 616632).8