Hypertriglyceridaemia in Alström's syndrome: causes and associations in 37 cases

To document frequency of severe hypertriglyceridaemia in Alström's syndrome (AS) and its relationship to hepatic and renal function, glycaemia and insulin resistance.

Thirty-seven subjects with AS aged 5-35 years, 51% male, were assessed at multidisciplinary clinics in Canada, UK and Italy. Diagnostic criteria were: severe cone/rod dystrophy leading to severe visual impairment in early childhood, sensorineural deafness, moderate overall obesity and normal intelligence. Three patients were treated with thyroxine for primary hypothyroidism and one female patient for secondary amenorrhoea with 20 micro g ethinyloestradial combined oral contraceptive. Two male patients were receiving monthly intramuscular testosterone enanthate for secondary hypogonadism. Fasting bloods were taken for serum insulin, serum glucose, serum triglycerides, hepatic and renal function and glycosylated Hb. Triglyceride levels > 8 mmol/l and fasting serum insulin levels > 16 microunits/ml were considered to represent severe hypertriglyceridaemia and severe insulin resistance, respectively. All subjects with (23) hypertriglyceridaemia also had high insulin resistance, as measured by HOMA modelling. However, there was no significant correlation between log tyriglyceride and log serum insulin or HOMA in the whole group (P = 0.2 and 0.14, respectively). There was no clear relationship between serum triglyceride levels and age, body mass index (BMI), hepatic or renal impairment or glycaemia.

The first overview of serum triglyceride levels in a significant number of reported cases of Alström Syndrome shows an overlap between severe hypertriglyceridaemia and severe hyperinsulinism, but not a direct correlation between the two nor with insulin resistance measured by HOMA. Triglyceride levels were not related to glycaemia, hepatic or renal dysfunction.