The Center for Cerebellar Malformations
Pancerebellar Hypoplasia
Cerebellar Hypoplasia
Cerebellar
hypoplasia is probably much more common that currently appreciated. Sporadic
nonsyndromic cerebellar hypoplasia was identified specifically in 11 of 2500
(0.5%) of children presenting to a pediatric neurologist (Shevell and Majnemer, 1996), although the prevalence of cerebellar hypoplasia is
approximately 5% in children presenting with developmental delay. The main clinical features of
cerebellar hypoplasia are developmental or speech delay, autistic features,
ataxia, hypotonia, and ocular signs (Wassmer et al., 2003). The
combination of speech delay, ataxia, hypotonia, autistic features, and ocular
signs, specifically oculomotor apraxia or nystagmus correctly predicts
cerebellar hypoplasia in the majority of patients.
It is
critical to differentiate cerebellar hypoplasia syndromes from cerebellar
atrophy syndromes, the latter characterized by progressive loss of cerebellar
volume and progressive symptoms.
It is impossible to confidently differentiate between these in every
case, but serial MRI finding, the presence of additional brainstem findings, or
symptoms consistent with one of the progressive syndromes are useful. Inborn metabolic disorders can affect
the cerebellum in its development and maturation (Steinlin et al., 1998).
Cerebellar hypoplasia also occurs with a wide variety of genetic
disorders, including nonprogressive autosomal recessive disorders as well as
situations in which it is sporadic (Ramaekers et al., 1997). In
several progressive metabolic and genetic disorders, diffuse cerebellar
hypoplasia is one of several characteristic features.
MRI Scans
Left-axial
view; middle and right sagittal views near midline.
Conditions with hemispheric
cerebellar hypoplasia
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Cerebellar ataxia |
Non-progressive ataxia,
mental retardation, dominant, recessive or X-linked |
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Lissencephaly with
cerebellar hypoplasia |
Severe retardation, ataxia,
elevated lipoprotein, mutations in reelin |
|
Cobblestone
lissencephaly syndromes |
Severe retardation,
congenital muscular dystrophy, retinal dysplasia |
Hoyeraal-Hreidarsson |
Aplastic anemia,
immunodeficiency, microcephaly, cerebellar hypoplasia, and growth
retardation, Xq28 |
|
Congenital disorder of glycosylation Ia |
Hypotonia, hyporeflexia,
ataxia, growth retardation, obesity, inverted nipples, dysmorphisms |
Gillespie |
Aniridia, ataxia, mental
retardation |