Acrocallosal syndrome

Acrocallosal syndrome is a rare condition characterized by a brain abnormality called agenesis of the corpus callosum, the presence of extra fingers and toes (polydactyly), and distinctive facial features. The signs and symptoms of this disorder are present at birth, and their severity varies widely among affected individuals.

Agenesis of the corpus callosum occurs when the tissue that connects the left and right halves of the brain (the corpus callosum) fails to form normally during the early stages of development before birth. Other brain abnormalities, including the growth of large cysts in brain tissue, have also been reported in people with acrocallosal syndrome. The changes in brain structure associated with this condition lead to delayed development and intellectual disability, which is most often moderate to severe. Some affected individuals also experience seizures.

Extra fingers and toes are common in people with acrocallosal syndrome. The extra digits can be on the same side of the hand or foot as the pinky or little toe (postaxial polydactyly) or on the same side as the thumb or great toe (preaxial polydactyly). Some affected individuals also have webbed or fused skin between the fingers or toes (syndactyly).

Distinctive facial features that can occur with acrocallosal syndrome include widely spaced eyes (hypertelorism) and a high, prominent forehead. Many affected individuals also have an unusually large head size (macrocephaly).

Other names

ACLS; Hallux duplication, postaxial polydactyly, and absence of corpus callosum; Schinzel acrocallosal syndrome; Schinzel syndrome 1

Inheritance pattern

Autosomal recessive; Autosomal dominant

Related genes

GLI3; KIF7

Source: MedlinePlus Genetics, U.S. National Library of Medicine.