MYOTONIC DYSTROPHY TYPE 2

MYOTONIC DYSTROPHY IS AN AUTOSOMAL DOMINANT DISORDER CHARACTERIZED MAINLY BY MUSCULAR DYSTROPHY CATARACTS, HYPOGONADISM, FRONTAL BALDING, AND ECG CHANGES. MYOTONIC DYSTROPHY TYPE 2 (DM2), IS RARE AND GENERALLY MANIFESTS WITH MILDER SIGNS AND SYMPTOMS THAN DM1. DM2 IS CAUSED BY HETEROZYGOUS EXPANSION OF A CCTG REPEAT IN INTRON 1 OF THE ZNF9 GENE (3Q21.3). INDIVIDUALS WITH DM2 HAVE MUSCLE PAIN AND STIFFNESS, PROGRESSIVE MUSCLE WEAKNESS, MYOTONIA, MALE HYPOGONADISM, CARDIAC ARRHYTHMIAS, DIABETES, AND EARLY CATARACTS. OTHER FEATURES MAY INCLUDE COGNITIVE DYSFUNCTION, HYPERSOMNIA, TREMOR AND HEARING LOSS.