XK‐aprosencephaly and related entities

We offer further biological characterization of the XK atelen/ aprosencephaly syndrome in two infants, one with prolonged survival, the other presenting prenatally with apparent hydranencephaly and an orbital tumor (OS). Familial occurrence in the former born to presumably non-consanguineous Lybian parents may represent parental germinal mosaicism or autosomal recessive inheritance. Both had apparently normal chromosomes; however, the Lybian infant had slightly increased induced chromosome breakage suggesting that this rare multiple congenital anomalies syndrome may involve a DNA repair defect. Virtual absence of atelen/aprosencephalic structures may lead to an arthrogryposis-like prenatal movement disorder. The orbital tumor in the Utah infant consisted of dystopic neural tissue compressing a rudimentary globe and was connected by a thin bridge of neural tissue to the small mass of disorganized brain tissue usually found in atelen/aprosencephalic infants and fetuses. No evidence of an encephaloclastic process was found in the autopsied Utah infant. © 2005 Wiley-Liss, Inc.