GENETIC-CHARACTERISTICS OF MYOADENYLATE DEAMINASE DEFICIENCY

Two types of myoadenylate deaminase (MAD) deficiency have been describ ed, primary or inherited, and secondary or acquired MAD deficiency. In this study, we investigated whether secondary MAD deficiency is indee d acquired or merely coincidental. We demonstrated the same underlying molecular defect, a C34T transition, in both types of deficiency. Fur thermore, the same frequency of the mutant MAD allele was found in the general population as in patients with neuromuscular complaints. We t herefore conclude that in the Dutch population, secondary MAD deficien cy is merely a ''coincidental'' finding, and that MAD deficiency is a harmless genetic variant.