X-linked recessive disease. MASA is an acronym for Mental retardation, Adducted thumbs, Shuffling gait, and Aphasia.

This disease is due to L1CAM germline mutations and is allelic with:
 X-linked hydrocephalus (MIM.307000)
 X-linked spastic paraplegia (MIM. 312900)
 X-linked hydrocephalus with colonic aganglionnosis (Hirschsprung disease)
 X-linked hydrocephalus with congenital idiopathic intestinal pseudoobstruction (MIM.300048)

Synopsis

 short stature (<5-15th percentile)
 microcephaly
 strabismus
 kyphosis
 lordosis
 adducted thumbs
 pes cavus
 equinovarus
 shuffling gait
 lower limb spasticity
 agenesis of the corpus callosum
 enlarged cerebral ventricles
 hydrocephalus

Etiology

 germline mutations in the L1CAM gene coding for L1 cell adhesion molecule gene (MIM.308840)