Alstrom Syndrome

Alstrom syndrome is a very rare autosomal recessive disorder characterised by progressive cone-rod dystrophy leading to blindness, sensorineural hearing loss, childhood obesity associated with hyperinsulinaemia, and type 2 diabetes mellitus.¹ The diagnosis should be considered in all patients with infantile cone and rod retinal dystrophy, especially if the weight is above the 90^th centile or if there is infantile cardiomyopathy.

• Dilated cardiomyopathy occurs in approximately 70% of patients during infancy or adolescence.²
• Renal failure, pulmonary, hepatic, and urological dysfunction are often observed, and systemic fibrosis develops with age.²
• The gene map locus for the affected mutated gene (ALMS1) is 2p12-13.³

• Alstrom syndrome is rare; only about 425 people worldwide are known to be affected.⁴

Alstrom syndrome in childhood is difficult to recognise without the development of infantile cardiomyopathy and may not be identified until diabetes mellitus develops in the second or third decade.

• Severe progressive infantile retinal dystrophy (visual acuity of 6/60 or less by 10 years of age and no light perception by age 20), with or without nystagmus
• Deafness
• Obesity
• Acanthosis nigricans
• Cardiomyopathy
• Nephropathy
• Alstrom may also be associated with:⁵
  • Hypothyroidism
  • Liver dysfunction
  • Metabolic abnormalities, including hyperuricaemia and elevated serum triglyceride and pre-beta-lipoprotein²
  • Small penis
  • Gastrointestinal reflux

• Bardet-Biedl syndrome is similar (with retinitis pigmentosa, deafness, obesity and diabetes mellitus) but also includes mental defect, polydactyly or hypogonadism.
• The retinal lesion of Alstrom syndrome causes nystagmus and early loss of central vision in contrast to the initial loss of peripheral vision found in other pigmentary retinopathies.

• Blood tests for fasting blood glucose, liver function tests, renal function tests, thyroid function tests and triglyceride levels
• A thorough assessment of vision and ophthalmoscopy by an Ophthalmologist
• Hearing assessment by an Ear, Nose and Throat specialist
• Assessment of heart function, including echocardiogram

There is no specific treatment but management will be required for:

• Diabetes
• Renal impairment
• Liver dysfunction
• Visual impairment
• Deafness
• Heart failure and other features of cardiomyopathy, e.g. cardiac arrhythmias
• Hypothyroidism

• The prognosis will depend on the progression of glucose intolerance, cardiomyopathy, renal dysfunction and liver impairment.
• Total blindness and deafness are likely to develop.