RTTN and tethered spinal cord syndrome: In total, 13/20 (65%) cases had positive results, including copy number variations of microdeletions at 17p13.3 (case 13, Miller–Dieker syndrome) and 6q22 (case 36) and pathogenic or likely pathogenic variants in TUBB3, TUBB, CYNC1HI, CCND2, IQSEC2, DPYSL5, RTTN, KIF11, OFD1, and TUBG1. With regard to the outcomes, 35 patients terminated their pregnancies, and 3 patients (1 case of multiple CNS anomalies, 1 case of pons hypoplasia, and 1 case of tethered spinal cord syndrome) delivered at term.