Table 1.

Case Definitions for MD STARnet

Case	Definition
Definite	A “definite” case has documented clinical symptoms referable to a dystrophinopathy and direct support of the diagnosis by at least one of these criteria: DNA analysis demonstrating a dystrophin mutation, OR A muscle biopsy demonstrating abnormal dystrophin, by either immunostaining or Western blot analysis. If there is a family history demonstrating X-linked inheritance, no additional information is required on the muscle. If the diagnosis is based solely on Western blot analysis of muscle biopsy and clinical symptoms, then there must be a description that allows confirmation that adequate numbers of intact muscle fibers were present in the sample to interpret the dystrophin results. If the diagnosis is based on immunostaining, supporting evidence is required from additional stains, for example utrophin, spectrin, nNOS, or dystroglycans OR An elevated CK an X-linked pedigree, and an affected family member who meets criterion (1) or (2) above.
Probable	A “probable” case has an elevated CK, a family history consistent with an X-linked muscular dystrophy, and documented clinical symptoms referable to a dystrophinopathy. Cases that have abnormal dystrophin results on muscle biopsy but lack the data required in the definition of ‘definite’ cases, above, are called “probable.”
Possible	A “possible” case has an elevated CK and documented clinical symptoms referable to a dystrophinopathy, but no muscle biopsy data, dystrophin mutation analysis, or family history to support the diagnosis. Cases that do not have CK information available in the clinical record, and who do not meet criteria for “definite” case, are called “possible.”
Asymptomatic	Asymptomatic individuals are those who have no clinical symptoms referable to a dystrophinopathy but who have laboratory results and/or a positive family history that will likely result in the development of a dystrophinopathy phenotype.
Female	Females are included in MD STARnet if they have onset of clinical symptoms referable to a dystrophinopathy appearing before age 21 years and either a dystrophin mutation or a muscle biopsy demonstrating abnormal dystrophin as required for “definite” case.
Not DBMD	Available information indicates case is definitely not Duchenne/Becker muscular dystrophy.

Abbreviations: CK, creatine kinase