[Show abstract][Hide abstract] ABSTRACT: Holoprosencephaly (HPE) is a brain malformation resulting from a primary defect in development of the basal forebrain during early gestation. Prenatal genetic and environmental factors and birth outcomes were described in a population of 104 children with holoprosencephaly referred to three clinical centers from 1998 through 2002. The mean child age was 4 years. Of cases karyotyped, 9% presented with a chromosomal abnormality. This study of living children with holoprosencephaly, the majority of whom are cytogenetically normal, provides new information on the subsample of children with a less severe phenotype. Most children were born at term; about 51% were microcephalic at birth. Consistent with previous research, the association between HPE and maternal history of diabetes merits further investigation. Several findings have important implications for future research. Only 22% of the children in this study sample were diagnosed with holoprosencephaly prenatally. The vast majority of children (72%) were diagnosed with HPE between birth and 1 year of age. Also, 19% of the cases referred to the Carter Centers with HPE were not confirmed on scan review. When possible, future population-based epidemiological studies should emphasize mechanisms that identify children with HPE outside of the newborn period and confirm the diagnosis by review of MRI or high quality CT brain scan.
Full-text · Article · Jul 2004 · American Journal of Medical Genetics Part A
[Show abstract][Hide abstract] ABSTRACT: Despite advances in neuroimaging and molecular genetics of holoprosencephaly (HPE), the clinical spectrum of HPE has remained inadequately described.
To better characterize the clinical features of HPE and identify specific neuroanatomic abnormalities that may be useful predictors of neurodevelopmental function.
The authors evaluated 68 children with HPE in a multicenter, prospective study. Neuroimaging studies were assessed for the grade of HPE (lobar, semilobar, and alobar), the degree of nonseparation of the deep gray nuclei, and presence of dorsal cyst or cortical malformation.
In general, the severity of clinical problems and neurologic dysfunctions correlated with the degree of hemispheric nonseparation (grade of HPE). Nearly three-quarters of the patients had endocrinopathies, with all having at least diabetes insipidus. The severity of endocrine abnormalities correlated with the degree of hypothalamic nonseparation (p = 0.029). Seizures occurred in approximately half of the children with HPE. The presence of cortical malformations was associated with difficult-to-control seizures. The presence and degree of dystonia correlated with the degree of nonseparation of the caudate and lentiform nuclei and the grade of HPE (p < 0.05). Hypotonia correlated with the grade of HPE (p < 0.05). Mobility, upper extremity function, and language correlated with the degree of nonseparation of the caudate, lentiform and thalamic nuclei, and grade of HPE (p < 0.01).
Patients with HPE manifest a wide spectrum of clinical problems and neurologic dysfunction. The nature and severity of many of these problems can be predicted by specific neuroanatomic abnormalities found in HPE.