Turner syndrome (TS) is an exclusively female genetic disease caused by complete or partial absence of the second X chromosome.

The karyotype is generally 45,X0 (80%) and more rarely 46X,Xp- or 46X,Xq- (5%); 15% of cases are mosaicism. It is the most commonly occurring chromosomal abnormality in women with an incidence of 1 in 2,500-3,000 births [1]. It is associated with a wide variety of anatomical and physiological abnormalities, especially related to the airway and cardiovascular system, which can pose a challenge to the anesthetist [2,3].

Physical characteristics comprise short stature, webbed neck, low set ears, micrognathia and retrognathia, cubitus valgus, widely spaced nipples and hypertelorism [1,4].

Cardinal systemic manifestations include gonadal dysgenesis and congenital lymphedema of the hands and feet [1,4]. Cardiovascular anomalies are present in 40-50% of patients, most commonly bicuspid aortic valve (25%) and aortic coarctation (10%), in addition to aortic stenosis, aortic root dilatation and a significant risk of aortic dissection. More rarely it is associated with ASD, VSD, anomalous pulmonary venous return and hypoplastic left heart [5].

There is an increased prevalence of cardiovascular disease, particularly hypertension, in addition to ischemic heart disease, cardiac conduction defects and hypercholesterolemia [1,5].

Endocrine manifestations include hypothyroidism, seen in 15-30% of patients with TS, and diabetes mellitus. There is an association with multiple autoimmune diseases [6].

Renal malformations are present in 40% of patients (absence, ectopic and horseshoe kidneys and duplication of the collecting duct), and gastro-esophageal reflux and inflammatory bowel disease are common [7-10]. Liver anomalies comprising hepatic steatosis, reduction in metabolism and bleeding disorders may be present [11-13].

Osteoarticular abnormalities may feature including scoliosis, kyphosis, osteoporosis and spina bifida occulta [14-16].

Ophthalmological and hearing impairment is common and 10% of patients with TS will have learning difficulties.