Molecular diagnostic testing for CFTR mutations complements the sweat test, which has been available for some time for confirmation of clinical diagnosis. Mutation analysis may provide insight, for example, when a patient is suspected of having cystic fibrosis but is too young to undergo a reliable sweat test. Indications for testing include clinical symptoms of cystic fibrosis, a family history of cystic fibrosis, and certain ethnic backgrounds. Gaucher disease occurs in all ethnic groups but is most common in the Ashkenazi Jewish population, among whom the incidence is approximately one in 450, and the carrier frequency is one in 10. Molecular diagnostic testing for Gaucher disease complements the glucocerebrosidase activity assay and may be used, for example, to clarify the finding of intermediate GC activity or to guide the choice of therapeutic regimen.
Mutation analysis is the method of choice for determination of carrier status.
The Molecular Genetics Laboratory offers analysis of four GC mutations. Becker is a milder form of muscular dystrophy that follows a clinical course similar to that of Duchenne but at a slower rate. Becker muscular dystrophy can present at any time from childhood to middle age and is associated with a range of symptoms, including hyperCKemia, proximal muscle weakness, easy fatigue, myoglobinuria, and muscle cramps. Duchenne and Becker are X-linked recessive disorders with an incidence of approximately one in 3,500 male births. Molecular diagnostic tests available through the Molecular Genetics Laboratory complement muscle biopsy immunofluorescence assays for disease diagnosis.