An X-linked syndromic intellectual disability characterized by developmental delay, intellectual disability with significant speech impairment, and short stature in male patients. Variable additional clinical features have been associated, including macrocephaly, seizures, tremor, gait abnormalities, hypogonadism, truncal obesity, behavioral disturbances and unspecific facial dysmorphism.

A measured foot length that is more than 2 SD below the mean for a newborn of 27 - 41 weeks gestation, or foot that is less than the 3rd centile for individuals from birth to 16 years of age (objective). Alternatively, a foot that appears disproportionately short (subjective).