Abstract
We present the clinical and histopathological features and the diagnostic difficulties
encountered in five children affected by a motor neuron disorder other than spinal
muscular atrophy. Investigations performed suggested the diagnosis of pontocerebellar
hypoplasia type 1 (PCH-1). Severe respiratory difficulty was present at birth in two
of these children; hypotonia, arthrogryposis, microcephaly and nystagmus were present
in all. Early and progressive bulbar involvement with swallowing difficulties and
stridor was also a common feature in these infants. Severe cognitive delay was invariably
present. Brain magnetic resonance imaging showed ponto-cerebellar hypoplasia in four
children while striking atrophy of the cerebellar vermis and cerebellar hemispheres
were present in the fifth child. Electrophysiological and pathological investigations
of proximal muscles performed at presentation in all these children were not conclusive,
while the post-mortem studies, or the study of distal muscles during life, showed
a clear neurogenic picture. Genetic studies excluded involvement of the SMN gene,
or of other genes located on chromosome 5q, confirming that ponto-cerebellar hypoplasia
type 1 is a different entity from typical proximal spinal muscular atrophy.
Key words
Ponto-cerebellar hypoplasia type 1 - Spinal muscular atrophy - Arthrogryposis
