Atelencephalic microcephaly: a case report and review of the literature.

Unlabelled: Atelencephalic microcephaly is a lethal form of abnormal cerebral development. In atelencephaly there is a rudimentary prosencephalon; in aprosencephaly, a more severe form of cerebral malformation, both prosencephalic and diencephalic derivatives fail to develop; both conditions form the aprosencephaly/atelencephaly spectrum (AAS). In the literature 20 cases with atelencephaly or aprosencephaly have been described. Except for the brain malformation other congenital abnormalities seem to be present more often in patients with aprosencephaly. In two patients (one with atelencephaly and one with aprosencephaly) an aberration of chromosome 13 was found. We report on a prematurely born microcephalic male infant with a severely malformed calvarium with overlying rugged skin, non-fused cranial sutures, absent fontanelles, and multiple contractures. CT scan of the brain revealed neither cerebral hemispheres, nor ventricles and a diagnosis of atelencephalic microcephaly was made. In the literature two sibs have been described, products of consanguineous parents, who were the only ones with cerebellar dysgenesis. Aprosencephaly/atelencephaly spectrum in combination with cerebellar dysgenesis seems to be an autosomal recessive syndrome.

Conclusions: Atelencephalic microcephaly is a distinct entity and should be differentiated from anencephaly and the fetal brain disruption sequence. The aetiology of the disorder is unknown.