A Paucisymptomatic Neuromuscular Disease Mimicking Type III 5q-SMA With Complex Rearrangements in the SMN Gene

作者：Lohkamp Laura Nanna; von Au Katja; Goebel Hans Hilmar; Kress Wolfram; Grieben Ulrike; Drossel Karin; Garbes Lutz; Wirth Brunhilde; Heppner Frank L; Stenzel Werner^*

来源：Journal of Child Neurology, 2014, 29(2): 254-259.

DOI：10.1177/0883073813511858

• deletion
• duplication
• SMN1 gene
• SMN2 gene
• spinal muscular atrophy

Spinal muscular atrophy is an autosomal-recessive neuromuscular disorder, causing progressive proximal weakness and atrophy of the voluntary muscles. More than 96% of the spinal muscular atrophy patients show a homozygous absence of exons 7 and 8, or exon 7 only, in SMN1, the telomeric copy of the SMN gene. We report a young male patient with neurogenic symptoms and sparse muscle fiber atrophy, suggestive of a mild form of type III spinal muscular atrophy. He was found to be a carrier of intragenic mutations in both copies of the SMN gene, exhibiting a homozygous duplication of exons 7 and 8 in SMN1 and a homozygous deletion of exon 8 as well as a heterozygous deletion of exon 7 in SMN2. 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.

• 出版日期2014-2