The method was developed on single blood leukocytes, obtained from healthy controls and an adult SMA type III patient with a known homozygous deletion of SMN1 exon 7 and 8.
Intragenic telSMN mutations: frequency, distribution, evidence of a founder effect, and modification of the spinal muscular atrophy phenotype by cenSMN copy number.
Three type III spinal muscular atrophy (SMA) families are described in which the same deletion pattern for SMN gene and flanking loci is apparent in both affected and unaffected siblings.
Intragenic telSMN mutations: frequency, distribution, evidence of a founder effect, and modification of the spinal muscular atrophy phenotype by cenSMN copy number.
The SMN gene for SMA and the HEXA gene for GM2 gangliosidosis were investigated in a woman with progressive proximal muscle weakness, long believed to be SMA type III (Kugelberg-Welander type).
Seven children (6.4 ± 2.0 years old, range four to ten; one SMA I, five SMA II, and one SMA III) treated with salbutamol (duration 23 ± 8 months) were assessed.
Here we show that a 46% reduction of Smn protein levels in the spinal cord of Smn heterozygous mice leads to a marked loss of the cytoplasmic Smn pool and motor neuron degeneration resembling spinal muscular atrophy type 3.
However, an intact full-length SMN1 complementary deoxyribonucleic acid was identified, and SMN protein levels in a muscle specimen were identical to that of a healthy control, formally excluding the diagnosis of spinal muscular atrophy III.
We suggest that the SMN2 gene copy quantification in SMA patients could be used as a prognostic tool for discrimination between the SMA type II and SMA type III diagnoses, whereas the FL-SMN/SMNΔ7 mRNA ratio could be a useful biomarker for detecting changes during SMA pharmacotherapy.
However, an intact full-length SMN1 complementary deoxyribonucleic acid was identified, and SMN protein levels in a muscle specimen were identical to that of a healthy control, formally excluding the diagnosis of spinal muscular atrophy III.
Here we show that a 46% reduction of Smn protein levels in the spinal cord of Smn heterozygous mice leads to a marked loss of the cytoplasmic Smn pool and motor neuron degeneration resembling spinal muscular atrophy type 3.