Table 2. Summary of tests conducted on patients from group 2 (families K–O).
| Family | Maternal mutation in SMN1 | Paternal mutation in SMN1 | NIPD outcomes (mat/pat) | Gestation | Foetal fraction | Invasive PND outcomes | Informative SNPs used | Haplotype blocks (mat/pat) | Classification accuracy | Average sequencing depth of informative SNPs used |
|---|---|---|---|---|---|---|---|---|---|---|
| K | 1 copy of exon 7 | 1 copy of exon 7 | Unaffected (N-ma/N-pa) | 11 weeks+3 days | 9.09% | Unaffected | 803 | 12/14 | 96% | 274 |
| L | 1 copy of exons 7 and 8 | 1 copy of exon 7 and 8 | Carrier (N-ma/M-pa) | 12 weeks | 10.67% | Carrier | 685 | 18/9 | 100% | 161 |
| M | 1 copy of exons 7 and 8 | 1 copy of exons 7 and 8 | Carrier (N-ma/M-pa) | 11 weeks+5 days | 10.91% | Carrier | 592 | 12/10 | 100% | 174 |
| N | 1 copy of exons 7 and 8 | 1 copy of exons 7 and 8 | Affected (M-ma/M-pa) | 12 weeks+4 days | 9.98% | Affected | 370 | 5/6 | 100% | 86 |
| O (P1) | 1 copy of exons 7 and 8 | 2 copies of exons 7 and 8 | Affected (M-ma/M-pa) | 11 weeks+2 days | 13.35% | Affected | 751 | 13/13 | 100% | 252 |
| O (P2) | 1 copy of exons 7 and 8 | 2 copies of exons 7 and 8 | Carrier (M-ma/N-pa) | 13 weeks+1 day | 16.49% | Unaffected | 665 | 12/12 | 100% | 158 |
Maternal and paternal SMA mutations for both parents were known from carrier screening tests conducted by MLPA analysis. Outcomes are reported as maternal and paternal inheritance of the haplotypes linked to the mutated (M-ma, M-pa) or normal (N-ma, N-pa) alleles. Prenatal diagnosis (PND) on the invasively obtained sample was conducted by MLPA analysis.