Musculoskeletal ImagingChromosomal abnormalities, with musculoskeletal manifestation
genetic disorders that involve either the autosomes or sex chromosomes, which may lead to a variety of musculoskeletal conditions. Many of these disorders are lethal. A chromosomal condition may involve a trisomy, in which three copies of one of the chromosomes are present; a
translocation, in which part of a chromosome becomes transposed to another chromosome; or a deletion, in which a portion of a chromosome is absent. Only the disorders that commonly involve the musculoskeletal system are described in this volume.
In 5p syndrome, the short arm of chromosome 5 is missing, resulting in a syndrome termed the cat cry or cri du chat syndrome.
Trisomy 8 syndrome is characterized by a large skull with a prominent bulging forehead, hypotelorism, a broad shallow nose, thick lips, a small mandible and a short neck.
Trisomy 13 syndrome is associated with mental retardation, seizures and apnoea. Other manifestations involve the musculoskeletal system and other organ systems.
Trisomy 18 syndrome leads to abnormalities of the cranium, cardiac anomalies, omphalocoele and renal defects.
Patients with trisomy 21 syndrome (Downs syndrome), have ocular abnormalities, hypotonia, brachycephaly, mental retardation, and sometimes developmental hip dysplasia. Turners syndrome occurs in persons with female phenotype and a 45,XO chromosome complement. Klinefelters syndrome usually results from the presence of two or more X chromosomes and a Y chromosome in persons who are phenotypically male.
DR