OBJECTIVE: To observe trinucleotide repeat number, (CTG)n in the 3'-untranslated region of the myotonic protein kinase (MTPK) gene in a clinically suspected woman with myotonic dystrophy (DM) family history and her abortus, in order to confirm the necessity of exerting antenatal examination in patients or suspected individuals with DM family history. METHODS: Long Expand Template polymerase chain reaction (PCR) system was used to analyze CTG trinucleotide repeat numbers located in the 3' untranslated region of MTPK on chromosome 19q13.2-3 in both peripheral white cells and muscles of the suspected mother and the other two DM patients in the family. The tissues of her abortus and blood of a health woman were detected, too. RESULTS: CTG repeats in both peripheral white cells and muscles of the suspected mother and the tissue of abortus were higher than normal range of CTG repeat number. There is no significant difference between blood and muscle samples. High CTG repeats were detected in blood and muscles of the typical DM members in the family, but in the blood sample of control, CTG repeats is normal. CONCLUSION: CTG trinucleotide analyses and antenatal examination should be done in pregnant with a DM family history, in order to reduce the birth rate of DM offspring.
