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.
These drugs are taken by mouth daily before each meal and could cause a drop in blood sugar. Metformin (biguanide): decreases the amount blood sugar being released by the liver and by stimulating the cells within muscles to take up blood sugar. Taken twice daily. Thiazolidinediones (rosiglitazone and pioglitazone): taken to help insulin work more efficiently in muscle and fat cells causing the liver to release less glucose. Is associated with heart failure. Dipeptidyl peptidase IV (DPP-4) inhibitors (sitagliptin): helps with improving blood sugar levels by decreasing the action of an enzyme breaking down GLP-1 (lowers the blood sugar level). Injected diabetes medicine: taken by an injection into the fat below the skin. Sometimes referred as subcutaneous injections. Some of these medications include the following:
Pramlintide (Symlin): is an Amylin agonist. It acts centrally (via the brain) to reduce food intake and blood sugar. It is most commonly used at mealtimes by people with type 1 and type 2 diabetes. Exenatide (Byetta): synthetic form of exendin-4 ( a GLP-1 receptor agonist that increases secretion of insulin, decreases the secretion of glucagon from the pancreas and reduces food intake). Cholesterol-lowering medications: is necessary when cholesterol levels are high. HMG-CoA reductase inhibitors, also called "statins," effectively lower levels of low-density lipoprotein, cholesterol and triglycerides. High-dose nicotinic acid (niacin) may also reduce cholesterol levels. Heart medications: Angiotensin-converting enzyme (ACE) inhibitors, diuretics, digoxin and beta-blockers may help with the management of cardiomyopathy and heart failure. Prognosis
A prognosis for Alström syndrome is complicated because it widely varies.