APA Dictionary of Psychology

n. any of several related inherited disorders (all dominant traits) that cause abnormalities of the skull, face, hands, and feet. Apert syndrome, Apert–Crouzon syndrome, and Pfeiffer’s syndrome (acrocephalosyndactyly Types I, II, and V) are due to different mutations in the FGFR2 gene (encoding fibroblast growth factor receptor) on chromosome 10. Chotzen’s syndrome (Type III) is due to a mutation in the TWIST gene on chromosome 7 (locus 7p21.3–21.2), which affects the expression of FGFR2.