NeurometPlus

Incidence

Transmitted as an autosomal recessive trait. Some cases are familial with paternal consanguinity (34 cases published worldwide).

Clinical Characteristics

Acrocallosal syndrome, Schinzel type is a rare genetic disorder that is apparent at birth. It is characterized by mental retardation, agenesis of corpus callosum, and distal anomalies of limbs. Mental retardation is variable but mostly severe, corpus callosum agenesis is associated with arachnoidal cysts in about one third of cases. Macrocephaly with protruding forehead and occiput have been described, and hypertelorism is frequent. Associated symptoms and findings may be variable, including among affected members of the same family. However, the disorder is typically characterized by hypoplasia or absence (agenesis) of the corpus callosum and moderate to severe mental retardation. In addition, many affected individuals have malformations of the craniofacial region and/or distinctive abnormalities of the fingers and toes. Characteristic craniofacial abnormalities may include an unusually large head (macrocephaly) with a prominent forehead; widely spaced eyes (ocular hypertelorism); downslanting eyelid folds (palpebral fissures); a small nose with a broad nasal bridge; and malformed or dysplastic ears. Most affected individuals also have distinctive digital malformations, such as the presence of extra (supernumerary) fingers and toes (polydactyly) and webbing or fusion (syndactyly) of certain digits. Additional physical abnormalities may also be present, including growth retardation, resulting in short stature. The triad of hypertelorism, polydactyly (especially of the halluces) and mental retardation strongly suggests the diagnosis which is further supported by magnetic resonance imaging showing absence of the corpus callosum and/or arachnoidal cysts. Although autosomal recessive inheritance has been suggested, acrocallosal syndrome often appears to occur randomly for unknown reasons (sporadically). In summary, there is absence of the corpus callosum with unusual facial appearance, mental deficiency, duplication of the halluces, and polydactyly.

Precipitants

None

Provocation Tests

None

Diagnostic Procedures

It is a clinical diagnosis. The triad of hypertelorism, polydactyly (especially of the halluces) and mental retardation strongly suggests the diagnosis which is further supported by magnetic resonance imaging showing absence of the corpus callosum and/or arachnoidal cysts.