Abstract | BACKGROUND: METHODS: We investigated the contributions of ISPD and GMPPB genes in a cohort of 174 Italian patients with LGMD, including 140 independent probands. Forty-one patients (39 probands) from this cohort had not been genetically diagnosed. The contributions of ISPD and GMPPB were estimated by sequential α-DG immunohistochemistry (IHC) and mutation screening in patients with documented α-DG defect, or by direct DNA sequencing of both genes when muscle tissue was unavailable. RESULTS: We performed α-DG IHC in 27/39 undiagnosed probands: 24 subjects had normal α-DG expression, two had a partial deficiency, and one exhibited a complete absence of signal. Direct sequencing of ISPD and GMPPB revealed two heterozygous ISPD mutations in the individual who lacked α-DG IHC signal: c.836-5 T > G (which led to the deletion of exon 6 and the production of an out-of-frame transcript) and c.676 T > C (p.Tyr226His). This patient presented with sural hypertrophy and tip-toed walking at 5 years, developed moderate proximal weakness, and was fully ambulant at 42 years. The remaining 12/39 probands did not exhibit pathogenic sequence variation in either gene. CONCLUSION: ISPD mutations are a rare cause of LGMD in the Italian population, accounting for less than 1% of the entire cohort studied (FKRP mutations represent 10%), while GMPPB mutations are notably absent in this patient sample. These data suggest that the genetic heterogeneity of LGMD with and without α-DG defects is greater than previously realized.
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Authors | Francesca Magri, Irene Colombo, Roberto Del Bo, Stefano Previtali, Roberta Brusa, Patrizia Ciscato, Marina Scarlato, Dario Ronchi, Maria Grazia D'Angelo, Stefania Corti, Maurizio Moggio, Nereo Bresolin, Giacomo Pietro Comi |
Journal | BMC neurology
(BMC Neurol)
Vol. 15
Pg. 172
(Sep 24 2015)
ISSN: 1471-2377 [Electronic] England |
PMID | 26404900
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Nucleotidyltransferases
- mannose 1-phosphate guanylyltransferase
- CRPPA protein, human
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Topics |
- Cohort Studies
- Humans
- Italy
- Muscular Dystrophies, Limb-Girdle
(genetics)
- Mutation
- Nucleotidyltransferases
(genetics)
- White People
(genetics)
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