Previously, we reported the relatively high incidence of a large deletion including the SMN1 region in Japanese spinal muscular atrophy type I patients.
The classical form of severe spinal muscular atrophy (SMA type 1; Werdnig-Hoffmann disease) has a very consistent clinical phenotype that is well recognized by paediatricians.
A Chinese male infant with arthrogryposis multiplex congenita (AMC), ventricular and atrial septal defects, and Werdnig-Hoffmann disease (WHD) had deletions of the telomeric copy of the survival motor neuron (SMN(T)) and neuronal apoptosis inhibitory protein genes.
However, molecular analysis revealed a homozygous deletion of exons 7 and 8 of the survival motor neuron (SMN) gene, suggesting that the patient had Werdnig-Hoffmann disease.
We report a child with clinical findings consistent with Werdnig-Hoffmann disease (spinal muscular atrophy type I) who was found not to have the homozygous absence of the survival motor neurone (SMN(T)) gene observed in approximately 95% of spinal muscular atrophy patients.
Missense mutation clustering in the survival motor neuron gene: a role for a conserved tyrosine and glycine rich region of the protein in RNA metabolism?
An 11 base pair duplication in exon 6 of the SMN gene produces a type I spinal muscular atrophy (SMA) phenotype: further evidence for SMN as the primary SMA-determining gene.
An 11 base pair duplication in exon 6 of the SMN gene produces a type I spinal muscular atrophy (SMA) phenotype: further evidence for SMN as the primary SMA-determining gene.
Typical of a large majority of such patients, both the child with spinal muscular atrophy type I and the child with type II were missing both copies of the survival motor neuron telomeric gene (SMN(T)).
Although this mutation, based on its histological description, was reported as a model for infantile spinal muscular atrophy of the Werdnig-Hoffmann type, its localization to a region that is not homologous with human 5q makes it unlikely to be a homologue to SMA.
The diagnostic muscle biopsy finding in severe infantile spinal muscular atrophy (Werdnig-Hoffmann disease, SMA type 1) is considered to be large-group atrophy with isolated clusters of hypertrophic type I myofibers.
In order to establish the incidence and prevalence of type I spinal muscular atrophy (SMAWerdnig-Hoffmann disease) in North Dakota, we reviewed the death certificates for the past 8 years.
A formal analysis of some possible intra-uterine and post-natal influences has been undertaken in 78 index cases (72 families) of acute infantile SMA (acute Werdnig-Hoffmann disease; SMA Type I).