<unk>  presents a wide variety of phenotypic symptoms. It is characterized by a combination of any of the following symptoms: * Central nervous system: mental retardation, microcephaly, gyral anomalies of the brain indicative of defects in migration of neural crest cells and neurons, abnormal EEG, hypoplasia of the corpus callosum and cerebella, and enlargement of the subarachnoid space * Cardiovascular: progressive aortic root dilation, mitral valve prolapse, and mitral regurgitation * Urogenital: Hirschsprung disease and constipation * Optical: megalocornea and pale optic discs with poor fixation * Dysmorphic facial features: hypertelorism, submucous cleft palate, sloping forehead, sparse eyebrows, depressed nasal bridge, bulbous nose, full lips, sparse hair, arched eyebrows, long eyelashes, ptosis, downslanting palpebral fissures, prominent ears, thick earlobes, prominent nasal bridge, thick philtrum, everted lower lip, and pointed chin * Anatomical abnormalities: camptodactyly and clinodactyly of the second to fourth toes, and hypotonia Additionally, while inconsistent, the following symptoms have been observed: * Congenital heart disease * Oligodontia * Scoliosis
Goldberg–Shprintzen syndrome
Schinzel–Giedion syndrome
Smith Martin Dodd syndrome
Shprintzen–Goldberg syndrome
Bardet–Biedl syndrome
Saethre–Chotzen syndrome
Pelger–Huët anomaly
Keppen–Lubinsky syndrome