title: Muscle Weakness: A Misleading Presentation in Children With Distinctive Syndromic Entities (Clinical Case Reports).
abstract: Marked ligamentous hyperlaxity and muscle weakness/wasting associated with awkward gait are the main deficits confused with the diagnosis of myopathy. Seven children (6 boys and 1 girl with an average age of 8 years) were referred to our department because of diverse forms of skeletal abnormalities. No definitive diagnosis was made, and all underwent a series of sophisticated investigations in other institutes in favor of myopathy. We applied our methodology through the clinical and radiographic phenotypes followed by targeted genotypic confirmation. Three children (2 boys and 1 girl) were compatible with the diagnosis of progressive pseudorheumatoid chondrodysplasia. The genetic mutation was correlated with theWISP 3gene actively expressed by articular chondrocytes and located on chromosome 6. Klinefelter syndrome was the diagnosis in 2 boys. Karyotyping confirmed47,XXY (aneuploidy of Klinefelter syndrome). And 2 boys were finally diagnosed with Morquio syndrome (MPS type IV A) as both showed missense mutations in the N-acetylgalactosamine-sulfate sulfatase gene. Misdiagnosis can lead to the initiation of a long list of sophisticated investigations.
authors.affiliation: Hanusch Hospital, Vienna, Austria; Orthopedic Hospital of Speising, Vienna, Austria.
authors.forename: Ali
authors.initials: A
authors.lastname: Al Kaissi
authors.affiliation: Iliazarov Center, Kurgan, Russian Federation.
authors.forename: Sergey
authors.initials: S
authors.lastname: Ryabykh
authors.affiliation: Iliazarov Center, Kurgan, Russian Federation.
authors.forename: Polina
authors.initials: P
authors.lastname: Ochirova
authors.affiliation: Pediatric Orthopedic Institute, Saint-Petersburg, Russia.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Kenis
authors.affiliation: Orthopedic Hospital of Speising, Vienna, Austria.
authors.forename: Jochen G
authors.initials: JG
authors.lastname: Hofstätter
authors.affiliation: Orthopedic Hospital of Speising, Vienna, Austria.
authors.forename: Franz
authors.initials: F
authors.lastname: Grill
authors.affiliation: Orthopedic Hospital of Speising, Vienna, Austria.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Ganger
authors.affiliation: Center of Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria.
authors.forename: Susanne Gerit
authors.initials: SG
authors.lastname: Kircher
keywords: 47,XXY (aneuploidy of Klinefelter syndrome); WISP 3 gene mutation; mutations in the N-acetylgalactosamine-sulfate sulfatase gene (GALNS gene); myopathy; progressive pseudorheumatoid arthritis