Telomeric Region of the Spinal Muscular Atrophy Locus Is Susceptible to Structural Variations.

Abstract

BACKGROUND:

Most patients with spinal muscular atrophy lack the survival motor neuron 1 gene (SMN1) in the telomeric region of the spinal muscular atrophy locus on chromosome 5q13. On the other hand, the copy number of SMN2, a centromeric homolog of SMN1, is increased in many of these patients. This study aimed to clarify the mechanism underlying these structural variations.

METHODS:

We determined the copy numbers of telomeric and centromeric genes in the spinal muscular atrophy locus of 86 patients and 22 control subjects using multiplex ligation-dependent probe amplification analysis. Then, we chose 74 patients lacking SMN1 exons 7 and 8, and compared their dataset with that of 22 control subjects retaining SMN1 exons 7 and 8.

RESULTS:

The SMN2 copy number was shown to vary widely and to correlate with the disease severity of the patients. Interestingly, telomeric NAIP and telomeric GTF2H2 showed similar tendencies. We also noted positive correlations among the copy number of SMN2 and the telomeric genes of the spinal muscular atrophy locus. However, the copy numbers of centromeric NAIP and centromeric GTF2H2 were stable among the patients, with both approximating a value of two.

CONCLUSION:

Our findings suggested that the telomeric region of the spinal muscular atrophy locus appears to be susceptible to structural variation, whereas the centromeric region is stable. Moreover, according to our results, new SMN2 copies may be generated in the telomeric region of the spinal muscular atrophy locus, supporting the SMN1-to-SMN2 gene conversion theory.

• Authors: Yoriko Noguchi, Akira Onishi, Yuji Nakamachi, Nobuhide Hayashi, Nur Imma Fatimah Harahap, Mawaddah Ar Rochmah, Ai Shima, Shinichiro Yanagisawa, Naoya Morisada, Taku Nakagawa, Kazumoto Iijima, Shimpei Kasagi, Jun Saegusa, Seiji Kawano, Masakazu Shinohara, Shinya Tairaku, Toshio Saito, Yuji Kubo, Kayoko Saito, Hisahide Nishio
• Journal: Pediatric neurology (Pediatr Neurol) Vol. 58 Pg. 83-9 (05 2016) ISSN: 1873-5150 [Electronic] United States
• PMID: 27268759 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2016 Elsevier Inc. All rights reserved.

Chemical References

• NAIP protein, human
• Neuronal Apoptosis-Inhibitory Protein
• SMN1 protein, human
• SMN2 protein, human
• Survival of Motor Neuron 1 Protein
• Survival of Motor Neuron 2 Protein

Topics

• Adolescent
• Adult
• Aged
• Centromere (genetics)
• Child
• Child, Preschool
• DNA Copy Number Variations
• Exons
• Female
• Genetic Loci
• Humans
• Infant
• Male
• Middle Aged
• Muscular Atrophy, Spinal (genetics)
• Neuronal Apoptosis-Inhibitory Protein (genetics)
• Severity of Illness Index
• Survival of Motor Neuron 1 Protein (genetics)
• Survival of Motor Neuron 2 Protein (genetics)
• Telomere (genetics)
• Young Adult