1998/03/01 by Jeffrey E Ming, Maximilian Muenke
paper · doi:10.1111/j.1399-0004.1998.tb02666.x
crossref issued 1998/03/01 · crossref published 1998/03/01 · crossref published-print 1998/03/01 · crossref published-online 2008/06/28 · crossref created 2010/07/19 · crossref deposited 2023/10/28 · crossref indexed 2026/07/30
Holoprosencephaly (HPE), a common developmental defect affecting the forebrain and face, is etiologically heterogeneous and exhibits wide phenotypic variation. Graded degrees of severity of the brain malformation are also reflected in the highly variable craniofacial malformations associated with HPE. In addition, individuals with microforms of HPE, who usually have normal cognition and normal brain imaging, are at risk for having children with HPE. Some obligate carriers for HPE may not have any phenotypic abnormalities. Recurrent chromosomal rearrangements in individuals with HPE suggest loci containing genes important for brain development, and abnormalities in these genes may result in HPE. Recently, Sonic Hedgehog (SHH) was the first gene identified as causing HPE in humans. Proper function of SHH depends on cholesterol modification. Other candidate genes that may be involved in HPE include components of the SHH pathway, elements involved in cholesterol metabolism, and genes expressed in the developing forebrain.