Abstract
Type I–IV proximal spinal muscular atrophy (SMA) is one of the most common autosomal-recessive diseases, which are characterized in the majority of cases by a severely disabling course. Proximal SMA results from mutations in the telomeric copy of SMN1 gene. Major SMN1 gene mutation types are deletions in the exons 7 and/or 8, which were revealed to be in the homozygous state in 95% of patients. Deletions in the indicated exons of SMN1 gene were revealed in a compound-heterozygous state in combination with intragenic point mutations in the remainder 5% of proximal SMA cases. In the present study, we performed an analysis of point mutations in eight patients with type I–III proximal SMA phenotype, which had a deletion in 7–8-exons of SMN1 gene in the heterozygous state. We revealed seven different mutations, two of which (c.824G>C (p.Gly275Ala) and c.825-2A>T) are described here for the first time. In addition, mutation c.824G>C (p.Gly275Ala) was observed twice in the examined sample. In seven cases a heterozygous carrier of point mutations was one of the parents of the affected children (in six cases, the father; in one case, the mother). Only one mutation, c.43C>T (p.Gln15X), emerged de novo in a generative cell or male cell of the child’s father.
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Original Russian Text © V.V. Zabnenkova, E.L. Dadali, S.B. Artemieva, I.V. Sharkova, G.E. Rudenskaya, A.V. Polyakov, 2015, published in Genetika, 2015, Vol. 51, No. 9, pp. 1075–1082.
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Zabnenkova, V.V., Dadali, E.L., Artemieva, S.B. et al. SMN1 gene point mutations in type I–IV proximal spinal muscular atrophy patients with a single copy of SMN1 . Russ J Genet 51, 925–931 (2015). https://doi.org/10.1134/S1022795415080128
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DOI: https://doi.org/10.1134/S1022795415080128