Holoprosencephaly (HPE) is the most common malformation of the embryonic forebrain in humans. Although HPE occurs along a continuous spectrum, it has been categorized into four types from most severe to least severe: alobar, semilobar, lobar, and middle interhemispheric (MIH) variant. Facial malformations are often associated with HPE and usually correlate with the severity of brain malformation. With the most severely affected newborns, there is a high mortality rate in the first month of life, however, with milder forms of HPE, the majority survive beyond infancy. The Carter Centers for Brain Research in Holoprosencephaly and Related Malformations have enrolled 182 living children in a prospective research study. Based on previously published reports using this database, reports from other investigators, as well as our experience and personal observations, the range of developmental, neurological, and medical problems found in children with HPE is described in this article. Virtually all children with HPE have some developmental disability and the severity correlates with the severity of the brain malformation on neuroimaging. Common medical problems include hydrocephalus, seizures, motor impairment, oromotor dysfunction with risk of poor nutrition and aspiration, chronic lung disease, gastroesophageal reflux, constipation, hypothalamic dysfunction with disturbed sleep-wake cycles and temperature dysregulation, as well as endocrine dysfunction. Diabetes insipidus in particular is found in about 70% of children with classic HPE. Recommendations for management of these problems are given based on experiences of the authors and familiarity with the literature.
2010 Wiley-Liss, Inc.