X-linked Infantile Spinal Muscular Atrophy

X-linked infantile spinal muscular atrophy: Clinical definition and molecular mapping

“…In this report, we extend our previous clinical and molecular investigations to eight new unrelated families with disease presentation and inheritance similar to that described by Greenberg et al 3 …”

“…19 However, neurogenic atrophy was not noted, indicating clinical heterogeneity even within forms of XL-SMA. In 1991, Borochowitz 14 reported two male siblings with a syndrome almost identical to that described by Greenberg et al 3 .…”

“…We have previously described meiotic breakpoint mapping (concordance analysis), and whole chromosome multipoint linkage analysis to the X-linked spinal muscular atrophy family reported by Greenberg et al 3 We showed localization of the disease gene to a pericentromeric interval from Xpll.3-qll.2 (Z max ϭ 2.63; between MAOB and the marker DXS991 1 ). In this report, we extend our previous clinical and molecular investigations to eight new unrelated families with disease presentation and inheritance similar to that described by Greenberg et al 3 …”

“…Two of these have been previously discussed. 2,3 A second multigenerational severe X-linked spinal muscular atrophy pedigree was reported almost a decade later. 19 However, neurogenic atrophy was not noted, indicating clinical heterogeneity even within forms of XL-SMA.…”

“…Progressive loss of anterior horn cells was cited as the cause of the severe lethal form of X-linked spinal muscular atrophy. Greenberg et al 3 described under the label "X-linked infantile spinal muscular atrophy" a similar disorder to X-linked spinal muscular atrophy Type I 2 that appeared to be X-linked recessive and was associated with hypotonia, areflexia, chest deformities, facial dysmorphic features, and congenital joint contractures (arthrogryposis). The findings of electromyography and muscle biopsy were consistent with autosomal recessive infantile spinal muscular atrophy (Werdnig-Hoffmann, MIM 253300).…”