Abstract for presentation at 11th International Congress of Human Genetics

Molecular analysis of common mutations associated with Spinal Muscular Atrophy (SMA) in Romanian families

  • Pompilia Apostol, Institute of Genetics, University of Bucharest, Romania
  • Danut Cimponeriu, Institute of Genetics, University of Bucharest, Romania
  • Monica Stavarachi, Institute of Genetics, University of Bucharest, Romania
  • Daniela Usurelu, Institute of Genetics, University of Bucharest, Romania
  • Niculina Butoianu, Department of Pediatrics Neurology I, “Alexandru Obregia” Hospital, Romania
  • Sanda Magureanu, Department of Pediatrics Neurology I, “Alexandru Obregia” Hospital, Romania
  • Irina Radu, Institute of Genetics, University of Bucharest, Romania
  • Lucian Gavrila, Institute of Genetics, University of Bucharest, Romania
  • Toma Mihai

    • Spinal muscular atrophy (SMA) is an autosomal recessive disorder characterized by degeneration of lower motor neurons leading to muscular weakness and atrophy. Any data regarding prevalence and carrier frequency in Romanian population are not available.
    The aim of our study was to analyze the most common mutations that occur in SMN and NAIP genes, causing SMA disease, in Romanian families.
    This is the first molecular test available for diagnosis of SMA in our country. Genetic counseling was provided to all the couples having a child affected by SMA.
    We investigated 45 SMA clinically diagnosed patients from “Al. Obregia” Hospital Bucharest, and their 34 relatives. All patients fulfilled the diagnostic criteria of SMA as defined by International SMA Consortium. We screened our subjects for the homozygous deletion of SMN genes exons 7 and 8 and NAIP exon 5, using PCR-RFLP and PCR techniques.
    The results are shown in Table:
    It is important to notice one homozygous deletion of SMN1 exons 7 and 8 among SMA III clinically diagnosed patient.
    Additionally, we have identified in the relatives group, only three particular homozygous deletion: SMN2 exons7+8, SMN2 exons7+8+ NAIP exon5, and NAIP exon5. Interestingly, their SMA type II(n=2) and III(n=1) clinically suspected children have no homozygous deletions in these exons. Supplementary studies are required for establish the meaning of this findings.

    Homozygous deletions SMA I SMA II SMA III
    SMN1 Exon 7 4 (15,4%) 1 (10%) 0 (0%)
    SMN1 Exon 8 4 (15,4%) 1 (10%) 0 (0%)
    NAIP Exon 5 0 (0%) 0 (0%) 0 (0%)
    SMN1 Exons 7 + 8 8 (30,8%) 1 (10%) 1 (11%)
    SMN1 Exons7 + 8 + NAIP Exon 5 5 (19,2%) 0 (0%) 0 (0%)
    SMN1 Exon 7 + NAIP Exon 5 1 (3,9 %) 1 (10%) 0 (0%)
    SMN1 Exon 8 + NAIP Exon 5 1 (3,9 %) 0 (0%) 0 (0%)
    None 3 (11,4%) 6 (60%) 8 (89%)
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