exudates and Spinal-Muscular-Atrophies-of-Childhood

The survival motor neuron 1 (SMN1) gene has been recognized to be responsible for spinal muscular atrophy (SMA) because it is homozygously deleted in more than 90% of SMA patients, irrespective of their clinical severity, whereas the neuronal apoptosis inhibitory protein (NAIP) gene is now considered to be a modifying factor of the severity of SMA. In Malaysia, it remains to be elucidated whether deletion of the SMN1 gene is also a main cause of SMA or whether deletion of the NAIP gene is found in the SMA patients.. To clarify the pathogenesis of SMA in Malaysia, a deletion analysis of the SMN1 and NAIP genes was performed in 24 Malaysian SMA patients. Deletion analysis of exons 7 and 8 of the SMN1 gene was performed according to the method described by van der Steege et al., while deletion analysis of exon 5 of the NAIP gene was performed according to a method described by Roy et al.. Homozygous deletion of SMN1 exon 7 and exon 8 were identified in 19 out of 24 patients (79%). As to the NAIP gene, deletion of exon 5 was detected in six out of 24 patients (25%). NAIP gene deletion was correlated with severity of the disease.. Deletion of the SMN1 exon 7 is a major cause of SMA in Malaysia, and NAIP gene deletions are not rare in type I SMA in Malaysia. The lower percentage of the SMN1 gene deletion may be due to the possibility that the present study included some patients without SMN1 gene abnormality and/or some patients with non-deletion type mutations in the SMN1 gene.

Topics: Asian People; Child; Child, Preschool; Chromosome Deletion; Cyclic AMP Response Element-Binding Protein; Female; Humans; Infant; Infant, Newborn; Malaysia; Male; Nerve Tissue Proteins; Neuronal Apoptosis-Inhibitory Protein; RNA-Binding Proteins; SMN Complex Proteins; Spinal Muscular Atrophies of Childhood; Survival of Motor Neuron 1 Protein

This study attempts to determine the type and relative frequency of muscle diseases contributing to floppy and hypotonic infants in Singapore.. Eighty consecutive muscle biopsies in the Department of Pathology, National University of Singapore, in the period 1978-2000, in which a clinical diagnosis of floppy or hypotonic infant was made, were reviewed.. The commonest cause of severe hypotonia in infancy was spinal muscular atrophy, which accounted for 33% of cases followed by congenital muscular dystrophy (13%). Eight cases (10%) of infantile type II glycogenosis (Pompe's disease) were encountered. There were seven cases of congenital myopathy, of which four were centronuclear myopathy, and one each of central core myopathy, nemaline myopathy and congenital fibre type disproportion. One case of centronuclear myopathy was associated with type I fibre smallness. Type II atrophy, which is generally considered a non-specific change, was encountered in five cases. Of interest is the relatively large number of muscle biopsies (29%) in which no significant pathological features were encountered at the light microscopic, histochemical as well as ultra-structural level.. The study has revealed a great variety of pathology affecting the muscle of children presenting as floppy infants or with hypotonia. The muscle diseases included spinal muscular atrophy, congenital muscular dystrophies, congenital myopathies and metabolic myopathies. However, 23 (29%) cases showed no significant pathology. For this group of floppy and hypotonic infants further studies are needed.

Topics: China; Female; Humans; India; Infant; Infant, Newborn; Malaysia; Male; Muscle Hypotonia; Muscle, Skeletal; Muscular Diseases; Sex Distribution; Singapore; Spinal Muscular Atrophies of Childhood