title: Congenital knee dislocation in a 49,XXXXY boy.
abstract: We report on a 12 year old mentally retarded boy who presented at birth with bilateral knee dislocations, dislocation of the right hip, and general joint laxity. Cytogenetic studies showed a 49,XXXXY karyotype. Hyperlaxity of joints is known to occur in 49,XXXXY patients, but congenital knee dislocation has not been reported. Rarely in 49,XXXXY and 49,XXXXX syndromes Larsen-like features may be seen. Patients with congenital joint dislocation or laxity, combined with other malformations, especially if psychomotor development is delayed, should be karyotyped to exclude chromosomal abnormalities.
authors.affiliation: Department of Medical Genetics, University of Groningen, The Netherlands.
authors.forename: R H
authors.initials: RH
authors.lastname: Sijmons
authors.forename: A J
authors.initials: AJ
authors.lastname: van Essen
authors.forename: J D
authors.initials: JD
authors.lastname: Visser
authors.forename: M
authors.initials: M
authors.lastname: Iprenburg
authors.forename: G F
authors.initials: GF
authors.lastname: Nelck
authors.forename: M L
authors.initials: ML
authors.lastname: Vos-Bender
authors.forename: B
authors.initials: B
authors.lastname: de Jong
mesh_terms: D000015:Abnormalities, Multiple / Q000235:genetics; D000328:Adult; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations / Q000235:genetics*; D002871:Chromosome Banding; D025063:Chromosome Disorders; D004551:Elbow Joint / Q000002:abnormalities; D005260:Female; D006618:Hip Dislocation, Congenital / Q000235:genetics; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D004204:Joint Dislocations / Q000151:congenital* / Q000235:genetics*; D007621:Karyotyping; D007719:Knee Joint / Q000002:abnormalities; D008214:Lymphocytes / Q000166:cytology / Q000502:physiology; D008297:Male; D011247:Pregnancy; D012785:Shoulder Joint / Q000002:abnormalities; D013933:Thumb / Q000002:abnormalities