Apparent gene conversions involving the SMN gene in the region of the spinal muscular atrophy locus on chromosome 5

Journal Article · Tue Oct 01 04:00:00 EDT 1996 · American Journal of Human Genetics

OSTI ID:476753

Steege, G van der; Grootscholten, P M; Cobben, J M; Scheffer, H; Buys, C H.C.M. ^[1]

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1. Univ. of Groningen (Netherlands); and others

The survival motor neuron (SMN) gene has been described as a determining gene for spinal muscular atrophy (SMA). SMN has a closely flanking, nearly identical copy ({sup C}BCD541). Gene and copy gene can be discriminated by sequence differences in exons 7 and 8. The large majority of SMA patients show homozygous deletions of at least exons 7 and 8 of the SMN gene. A minority of patients show absence of SMN exon 7 but retention of exon 8. This is explained by results of our present analysis of 13 such patients providing evidence for apparent gene-conversion events between SMN and the centromeric copy gene. Instead of applying a separate analysis for absence or presence of SMN exons 7 and 8, we used a contiguous PCR from intron 6 to exon 8. In every case we found a chimeric gene with a fusion of exon 7 of the copy gene and exon 8 of SMN and absence of a normal SMN gene. Similar events, including the fusion counterpart, were observed in a group of controls, although in the presence of a normal SMN gene. Chimeric genes as the result of fusions of parts of SMN and {sup C}BCD541 apparently are far from rare and may partly explain the frequently observed SMN deletions in SMA patients. 23 refs., 4 figs.

• OSTI ID: 476753
• Journal Information: American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: 4 Vol. 59; ISSN AJHGAG; ISSN 0002-9297
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
CHIMERAS
DISEASES
DNA SEQUENCING
EXONS
GENE MUTATIONS
GENES
GENETIC MAPPING
HEREDITARY DISEASES
HUMAN CHROMOSOME 5
INTRONS
MUSCLES
MUTATION FREQUENCY
PATIENTS
POLYMERASE CHAIN REACTION
RECESSIVE MUTATIONS
TRANSCRIPTION