large iranian family with myotonic dystrophy

ABSTRACT

We report on the first observation of an Iranian family with myotonic dystrophy [Steinert disease]. The proband was 26 years old and had suffered a long history of progressive myotonia and muscular weakness. He presented with frontal baldness, ptosis, bilateral facial weakness, unclear speech, and mental retardation. The disease onset was probably at birth. The diagnosis was made by detection of a large expansion of the CTG repeat in the DM Protein kinase gene [DMPK] on chromosome 19. In the proband's family, there were at least 11 affected members in three generations. There is clear evidence of anticipation as the disease manifested itself earlier in successive generations with increasing severity associated with gains of repeat sizes on transmission from parent to offspring. The chromosomal background of this mutation corresponded to the background of other DM mutations in the European population