The 5q-SMA screening via qPCR typically covers approximately 95% of patients, but the remaining 5% may yield false negatives due to compound heterozygotes (with an SMN1 exon 7 deletion in one allele and a subtle variant in the other allele) or homozygotes carrying alterations beyond the exon 7 deletion in SMN1. The gene discussed is SMN1; the disease is proximal spinal muscular atrophy.