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.
References
Further reading
Group A Streptococcal Infections - National Institute of Allergy and Infectious Diseases
Wilkins, Lippincott Williams & (2004-01-01). Rapid Assessment: A Flowchart Guide to Evaluating Signs and Symptoms. Lippincott Williams & Wilkins. ISBN 9781582552729. == External links ==