title: Presymptomatic diagnosis of SMA III by genotype analysis.
abstract: Linkage analysis and prenatal prediction in families segregating autosomal recessive spinal muscular atrophy (SMA) has become feasible since the assignment of the locus responsible for type I-III SMA to region 5q12-q13.3. We have performed a segregation study of SMA in Italian families using molecular probes and highly informative PCR-based polymorphic markers. In one family, a 7-year-old boy affected with type III SMA and an 8-year-old apparently healthy brother had identical haplotypes. These findings prompted us to reexamine the apparently unaffected child. His neurological exam was normal. However, the electromyography (EMG) showed a pattern consistent with chronic SMA. To our knowledge this is the first example of presymptomatic diagnosis of SMA based on genotype analysis.
authors.affiliation: Istituto di Genetica Medica, Facoltà di Medicina A. Gemelli, Università Cattolica, Rome, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Brahe
authors.forename: S
authors.initials: S
authors.lastname: Zappata
authors.forename: I
authors.initials: I
authors.lastname: Velonà
authors.forename: E
authors.initials: E
authors.lastname: Bertini
authors.forename: S
authors.initials: S
authors.lastname: Servidei
authors.forename: P
authors.initials: P
authors.lastname: Tonali
authors.forename: G
authors.initials: G
authors.lastname: Neri
mesh_terms: D001483:Base Sequence; D002648:Child; D004247:DNA / Q000235:genetics; D004576:Electromyography; D005838:Genotype; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009134:Muscular Atrophy, Spinal / Q000145:classification / Q000175:diagnosis* / Q000235:genetics*; D010375:Pedigree
chemical_list: D004247:DNA