Molecular diagnosis and counseling in a family presenting compound heterozygosity for autosomal recessive limb-girdle muscular dystrophy.

The present report concerns two patients, male and female siblings, manifesting a different degree of severity for the same autosomal recessive limb-girdle muscular dystrophy. The index case (male sib) carried the clinical diagnosis of Becker muscular dystrophy at the time when the sister, with a much milder presentation, first sought counseling and prenatal diagnosis for a pregnancy already in course. Molecular and immunocytochemical tests then available favoured the diagnosis of an autosomal recessive myopathy, but did not enable exclusion of a dystrophinopathy The couple was counseled accordingly, although prenatal diagnosis could not be offered. Both patients were later found to carry one gamma- and two alpha-sarcoglycan gene mutations, one of the latter being new This raised a counseling dilemma: depending on which combination was the disease-causing genotype, there would be a minimal or a significant 25% risk to offspring. We describe the studies carried out and emphasise the importance of differential diagnosis and extensive molecular characterisation in this group of disorders, so as to enable correct genetic counseling and prenatal diagnosis.