title: Bone and Spinal Muscular Atrophy.
abstract: Spinal Muscular Atrophy (SMA) is an autosomal recessive neuromuscular disease, leading to progressive denervation atrophy in the involved skeletal muscles. Bone status has been poorly studied. We assessed bone metabolism, bone mineral density (BMD) and fractures in 30 children (age range 15-171 months) affected by SMA types 2 and 3. Eighteen children (60%) had higher than normal levels of CTx (bone resorption marker); 25-OH vitamin D was in the lower range of normal (below 20 ng/ml in 9 children and below 12 ng/ml in 2). Lumbar spine BMAD (bone mineral apparent density) Z-score was below -1.5 in 50% of children. According to clinical records, four children had sustained four peripheral fractures; on spine X-rays, we observed 9 previously undiagnosed vertebral fractures in 7 children. There was a significant inverse regression between PTH and 25-OH D levels, and a significant regression between BMC and BMAD values and the scores of motor-functional tests. Even if this study could not establish the pathogenesis of bone derangements in SMA, its main findings - reduced bone density, low 25OH vitamin D levels, increased bone resorption markers and asymptomatic vertebral fractures also in very young patients - strongly suggest that even young subjects affected by SMA should be considered at risk of osteopenia and even osteoporosis and fractures.
authors.affiliation: Experimental Laboratory for Children's Bone Metabolism Research, Bone Metabolism Unit, Institute Auxologico Italiano IRCCS, Milan, Italy. Electronic address: s.vai@auxologico.it.
authors.forename: Silvia
authors.initials: S
authors.lastname: Vai
authors.affiliation: Experimental Laboratory for Children's Bone Metabolism Research, Bone Metabolism Unit, Institute Auxologico Italiano IRCCS, Milan, Italy.
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Bianchi
authors.affiliation: Child Neurology Unit, Carlo Besta Neurological Institute Foundation, Milan, Italy.
authors.forename: Isabella
authors.initials: I
authors.lastname: Moroni
authors.affiliation: S.A.PRE., Ospedale Policlinico Maggiore Mangiagalli, and Regina Elena Foundation, Milan, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Mastella
authors.affiliation: Experimental Laboratory for Children's Bone Metabolism Research, Bone Metabolism Unit, Institute Auxologico Italiano IRCCS, Milan, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Broggi
authors.affiliation: Neuromuscular Disease and Immunology Unit, Carlo Besta Neurological Institute Foundation, Milan, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Morandi
authors.affiliation: Developmental Neurology Unit, Carlo Besta Neurological Institute Foundation, Milan, Italy.
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Arnoldi
authors.affiliation: Developmental Neurology Unit, Carlo Besta Neurological Institute Foundation, Milan, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Bussolino
authors.affiliation: Developmental Neurology Unit, Carlo Besta Neurological Institute Foundation, Milan, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Baranello
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D015519:Bone Density / Q000502:physiology*; D001842:Bone and Bones / Q000378:metabolism*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D016103:Spinal Fractures / Q000453:epidemiology; D014897:Spinal Muscular Atrophies of Childhood / Q000150:complications*
keywords: 25-hydroxyvitamin D; Bone mineral density; Fractures; Osteoporosis; Spinal Muscular Atrophy