Signs and symptoms
Symptoms for Alström syndrome generally appear during infancy with great variability in age. Some of the symptoms include:
Heart failure (dilated cardiomyopathy) in over 60% of cases, usually within the first few weeks after birth, but sometimes the onset is in adolescence or adulthood. Light sensitivity and vision problems (cone-rod dystrophy) in all cases, usually within 15 months of birth and progressively worsening until about 20 years of age
Delays in early, developmental milestones in 50% of cases, learning disabilities in about 30% of cases
Obesity in 100% of cases, apparent by 5 years of age but often apparent in infancy (Alström infants usually have normal birth weights, and by adolescence, weights tend to be in the high-normal to normal range.) Nystagmus (usually affects the children), one of the first symptoms to occur which causes involuntary rapid eye movement. Mild to moderate bilateral sensorineural hearing loss. Type 2 diabetes usually occurs in early childhood. Hyperinsulinemia/insulin resistance—development of high level of insulin in blood. Hypertriglyceridemia
Steatosis (fatty liver) and elevated transaminases (liver enzymes) often develop in childhood and can progress in some patients to cirrhosis and liver failure. Endocrine dysfunctions may occur where the patient may experience an under or over active thyroid gland, weak growth hormone, increased androgen in females and low testosterone in males. Slowly progressive kidney failure can occur in the second to fourth decade of life. Cause
Alström syndrome is caused by a mutation in the ALMS1 gene, located on the short arm of chromosome 2 (2p13.2).
In addition, examinations for the nervous system or the eyes may be performed. Various imaging studies like computerized tomography scans (CT), Magnetic Resonance Imaging (MRI) or X-rays are used to see the structures within the body.Family and personal medical history are required. Information about the health of an individual is crucial because it provides traces to a genetic diagnosis.Laboratory tests, particularly genetic testing, are performed to diagnose genetic disorders. Some of the types of genetic testing are molecular, biochemical and chromosomal. Other laboratory tests performed may measure levels of certain substances in urine and blood that can also help suggest a diagnosis. Related disorders
Recent findings in genetic research have suggested that a large number of genetic disorders, both genetic syndromes and genetic diseases, that were not previously identified in the medical literature as related, may be, in fact, highly related in the genetypical root cause of the widely varying, phenotypically-observed disorders. Thus, Alstrom syndrome is a ciliopathy. Other known ciliopathies include primary ciliary dyskinesia, Bardet–Biedl syndrome, polycystic kidney and liver disease, nephronophthisis, Meckel–Gruber syndrome and some forms of retinal degeneration. Diagnostic criteria
Marshall JD et al. provided a comprehensive guidance for diagnostic criteria in their 2007 publication.Birth – 2 years:
Minimum diagnosis requires 2 major criteria or 1 major and 2 minor criteria. Major criteria are:

ALMS1 mutation in 1 allele and/or family history of Alström syndrome
Vision pathology (nystagmus, photophobia).Minor criteria are:

Obesity
Dilated cardiomyopathy with congestive heart failure.Other variable supportive evidence:
Recurrent pulmonary infections, normal digits, delayed developmental milestones.