Laryngeal hypoplasia is the most common laryngeal
anomaly described. Tracheal intubation for respiratory failure as a
consequence of hypotonia may be necessary in the neonatal period. Cerebellar
and brainstem hypoplasia are described in addition to corpus callosum
agenesis. Seizures have been a feature in some patients. Mental retardation
may be severe. Congenital heart disease appears to be a common, although
inconsistent, finding.