Medical Genetics

Down syndrome is a chromosomal condition caused by an extra copy of chromosome 21, with variable learning disability, hypotonia and characteristic features plus a higher chance of treatable cardiac, gastrointestinal, endocrine, hearing, visual, sleep, haematological and neurological problems.

A group of heritable connective-tissue disorders with variable joint, skin and tissue fragility; hypermobile EDS and hypermobility spectrum disorder are usually clinical diagnoses, while vascular EDS is rare and can cause arterial, bowel or uterine rupture.

An autosomal-dominant neurodegenerative disorder caused by a CAG-repeat expansion in HTT, producing progressive motor, cognitive and psychiatric change; diagnosis and predictive testing require specialist genetics support and treatment is symptomatic and multidisciplinary.

A sex-chromosome condition, usually 47,XXY, causing variable testicular dysfunction and androgen deficiency; it may present with small firm testes, tall stature, gynaecomastia, learning or psychosocial needs, delayed puberty or infertility and is often diagnosed late.

An autosomal-dominant FBN1-related connective-tissue disorder affecting the aorta, eyes and skeleton; tall stature and ectopia lentis are recognisable clues, but progressive aortic-root disease and dissection are the life-threatening priorities.

A sex-chromosome condition caused by complete or partial loss of one X chromosome, usually 45,X or mosaic, with variable short stature, ovarian insufficiency and characteristic cardiac, renal, hearing, metabolic and learning needs; aortic disease makes lifelong cardiovascular care essential.