FIRST-TRIMESTER PRENATAL-DIAGNOSIS OF SPINAL MUSCULAR-ATROPHY USING MICROSATELLITE MARKERS

Twenty-five pregnancies at risk for spinal muscular atrophy I (SMA I) have been monitored by first-trimester prenatal diagnosis. Microsatell ite markers were used in ah cases to amplify polymorphic regions at th e D5S125, D5S435, D5S39, D5S127, and D5S112 loci. All families, includ ing 12 SMA I pedigrees with a deceased index child, were fully informa tive for DNA analysis. Three fetuses were predicted to be affected and 22 fetuses were predicted to be unaffected. Twenty-two newborns were unaffected by clinical examination at birth. These results support the accuracy of SMA I prenatal diagnosis based on linkage analysis.