[Clinical features and genetic analysis of a fetus with holoprosencephaly].

OBJECTIVE: To analyze the clinical features and pathogenesis of a fetus with holoprosencephaly. METHODS: The findings of prenatal ultrasonography was reviewed. Following elective abortion, whole exome sequencing (WES) was carried out to identify potential pathogenic variant. Copy number variants (CNVs) of the abortus and its parents were detected by low-depth high-throughput sequencing. The parents were also analyzed by chromosomal karyotyping. RESULTS: Prenatal ultrasound suggested that the fetus had holoprosencephaly. WES revealed that it had approximately 33 Mb deletion at chromosome 13 involving ZIC2, a haploid dose sensitive gene. The results of low-depth high-throughput sequencing confirmed that the fetus carried a de novo 32.32 Mb deletion at 13q31.1-34. Karyotyping analysis has excluded gross chromosomal aberration in both parents. CONCLUSION: The fetus was diagnosed with holoprosencephaly, which may be attributable to the 13q31.1-34 deletion involving the ZIC2 gene.

Birthweight is an independent predictor of birth asphyxia in twins: A retrospective cross-sectional cohort study of 5337 Chinese twins.

OBJECTIVE: Few studies are available on birth asphyxia risks in twin neonates. This retrospective multi-center cross-sectional study determined the birthweight percentiles of 5337twins and birth asphyxia incidence of the twin population. METHODS: We retrieved sociodemographic and obstetric data from the electronic records systems of participating centers. Neonate birthweight was measured within 24 h of birth. Perinatal asphyxia was diagnosed if 5-minute Apgar score was ≤5, or resuscitation was required 10 min after birth. The primary outcome was the incidence of birth asphyxia. RESULTS: Totally 5337 neonates were eligible. The mean neonatal birthweight was 2227.1 ± 608.99 g and the 5th, 50th, and 95th percentiles of birthweight were 970, 2400, and 3080 g, respectively. The mean Apgar score was 9.06 ± 1.73 at 1 min and 8.99 ± 1.74 at 5 min. Totally 13.5 % (705/5222) twins had asphyxia and 9.35 % and 4.16 % twins had moderate and severe asphyxia, respectively. Twins with a birthweight< 1500 g had the highest asphyxia rate (64.8 %) and twins with a birthweight between 2500 and 3000 g had the lowest asphyxia rate (3.6 %). Stepwise logistic regression analysis revealed that higher birthweight was associated with a significantly reduced risk of asphyxia [OR 0.772 (95 %CI 0.755, 0.789), P < 0.001]. The AUROC for mean twin birthweight was 0.86±0.01 (95 %CI 0.84, 0.88) using a cutoff of 1950 g, with a sensitivity of 0.84 and a specificity of 0.78. CONCLUSION: Twins have lower birthweight versus singletons and a significant proportion of twins, especially twins with lower birthweight, are at risk of birth asphyxia. Birthweight is an independent predictor of asphyxia and should be further explored as a predictive marker for stratifying asphyxia risks in twin neonates.