Absent or abnormal ribs. Vertebral abnormalities include hemivertebrae and scoliosis. Agenesis of the corpus callosum and salaam seizures with occasional ventriculomegaly, cortical heterotopias, choroid plexus papilloma, and Dandy-Walker anomaly. Seizures are present in most cases, including infantile spasms, grand mal epilepsy, twitching, and staring spells. Abducent nerve paralysis may occur.
Recurrent pneumonia is a frequent complication.
Occasional hiatal hernia. Transmitted as an X-linked dominant trait with embryonic lethality in hemizygous males.