CARRIER DETECTION OF DUCHENNE MUSCULAR-DYSTROPHY THROUGH ANALYSIS OF DNA FROM DECIDUOUS TEETH OF A DEAD AFFECTED CHILD

The sister of a child affected by Duchenne muscular dystrophy (DMD) wa s referred for genetic counselling to assess the risk of her being a c arrier. Her brother had died 15 years previously at the age of 8, Ther e were no other affected males in the family. There were no methods fo r DNA investigation at the time of the child's death and the family ha d never been studied for linkage with polymorphic probes on the chromo somal region Xp21. The only tissue from which an assessment of the ris k could be made by DNA linkage analysis was two of the child's deciduo us teeth that the parents had kept. DNA was extracted using a protocol described for the recovery of ancient DNA from museum specimens and a rchaeological finds. Multiplex amplification did not reveal deletions in 19 exons spanning the hot-spot regions for deletions within the dys trophin gene in Xp21. Linkage analysis using three highly polymorphic microsatellites demonstrated that the sister had not received the X ch romosome borne by her brother. These results show that DNA extracted f rom teeth is a reliable source for molecular diagnosis.