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How are mucolipidoses (MLs) diagnosed?

Doctors can use genetic tests to diagnose mucolipidoses. These tests look for specific genes that cause the different mucolipidoses diseases. Some mucolipidoses diseases can be diagnosed from stomach acid samples. Doctors may also take a medical history and observe a person's symptoms. Mucolipidoses can be diagnosed in early pregnancy with a test called chorionic villus sampling (CVS).

Another way to confirm the diagnosis is through skin biopsy. A small sample of skin is taken from the patient and grown in a cell culture. The activity of a particular enzyme in the cultured skin cells is then measured.

ML IV is suspected when cells that are easily obtained by conjunctival swabbing are found to have numerous inclusions. In addition, measurement of the level of gastrin in the blood, which is significantly increased in ML IV patients, helps to confirm the diagnosis.

Scientists have identified the genes responsible for all four types of MLs. In 2000, scientists at NINDS laboratories and other research institutions identified the gene responsible for ML IV. This gene, MCOLN1, makes the protein mucolipin-1. Due to mutations in the gene, mucolipin-1 is missing or dysfunctional in people with ML IV. This important genetic finding allows for the accurate diagnosis of patients, as well as prenatal (before birth) diagnosis, and the screening of carriers of the disease.

Prenatal diagnosis for ML is accomplished using a procedure known as chorionic villus sampling (CVS). This procedure is usually done around the eighth or tenth week of pregnancy and involves removing and testing a very small sample of the placenta. For ML types I, II, and III, placental cells called amniocytes are grown in culture and then tested to measure enzyme activity levels. For ML IV, no culture is required. DNA is obtained directly from the amniocytes and analyzed for mutations consistent with ML IV. This technique is called genotyping.

This answer is based on source information from National Institute of Neurological Disorders and Stroke.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.