Distal trisomy 18q is a rare, partial autosomal trisomy characterized by a variable phenotype that includes hypotonia, motor delay, mild to severe intellectual disability, seizures, variable cerebral anomalies, finger/toe syndactyly, fifth finger clinodactyly, strabismus, short neck and dysmorphic facial features.

Height of the palate more than 2 SD above the mean (objective) or palatal height at the level of the first permanent molar more than twice the height of the teeth (subjective).