PT - JOURNAL ARTICLE AU - L Martorell AU - J M Martinez AU - N Carey AU - K Johnson AU - M Baiget TI - Comparison of CTG repeat length expansion and clinical progression of myotonic dystrophy over a five year period. AID - 10.1136/jmg.32.8.593 DP - 1995 Aug 01 TA - Journal of Medical Genetics PG - 593--596 VI - 32 IP - 8 4099 - http://jmg.bmj.com/content/32/8/593.short 4100 - http://jmg.bmj.com/content/32/8/593.full SO - J Med Genet1995 Aug 01; 32 AB - Myotonic dystrophy (DM) is associated with an underlying CTG trinucleotide repeat expansion at a locus on chromosome 19q13.3. We have determined the repeat length in 23 DM patients with varying clinical severity of symptoms and various sizes of repeat amplification. We confirm that as in previous studies there is no strong correlation between repeat length and clinical symptoms but find that the repeat length in peripheral blood cells of patients increases over a time span of five years indicating continuing mitotic instability of the repeat throughout life. Repeat length progression does not appear to be indicative of clinical progression but age probably is. The degree of expansion correlates with the initial repeat size and 50% of the patients with continuing expansions showed clinical progression of their disease symptoms over the five year study period.