Genetics: autosomal recessive, almost exclusively in Eastern European Ashkenazi Jewish people. One of two possible mutations in IKBKAP gene on chromosome 9.

Pathogenesis: impaired synthesis of NE.

Clinical features in infancy: low birth weight, breech presentation, hypotonia, diminished tendon reflexes, no corneal responses, poor Moro reflex, weak cry and suck, breath-holding spells. Tongue tip lacks fungiform papillae, appears smooth. Risk aspiration pneumonia from impaired swallowing, gastroesophageal reflux. Lack of overflow tears risks corneal ulceration.