Mednax, Sunshine, FL, United States.
Autism Research Texas, Houston, TX, United States.
Front Cell Infect Microbiol. 2021 Jul 19;11:676988. doi: 10.3389/fcimb.2021.676988. eCollection 2021.
The objectives are to estimate the vertical transmission rate in twins relative to singleton pregnancies, to evaluate whether discordance within twin pairs is rare, and to characterize concordance within monozygotic and dizygotic twin pairs in relation to hereditability.
We first sought to estimate the vertical transmission rate of congenital CMV infection in twins by gathering cohort-based studies of congenital CMV in which vertical transmission in both singleton and twin pregnancies was reported. This also allowed us to compare singleton and twin infection rates. From the above studies and other large cohorts of congenitally infected infants, the percentage of discordantly infected twin pairs determined whether this is a rare phenomenon. Theorizing discordance is not rare, we then analyzed data from cases with twin outcomes for congenital CMV infection, according to whether the twins were monozygotic or dizygotic, and calculated their corresponding concordance rates to estimate the broad-sense heritability. Lastly, we described other factors that might affect vertical transmission.
From five articles following at-risk pregnancies, the rate of vertical transmission in twin pregnancies is 58.7% (95% CI 43.3-72.3%) whereas in singleton pregnancies it is 31.4% (95% CI: 29.0-34.0%) = 0.0002. Of ten studies of larger cohorts of infants with congenital CMV infection, 21 of 42 twin pairs with at least one twin infected were discordant for congenital CMV (50.0%, 95% CI: 34.4-65.6%) indicating discordance of congenital CMV infection in twin pairs is not rare. Of 28 studies covering 37 twin pairs where at least one twin had congenital CMV, and zygosity was known, eleven of thirteen monozygotic twin pairs (84.6%; 95% CI: 53.7-97.3%) were concordant for CMV infection, and nine of twenty-four dizygotic twin pairs (37.5%; 95% CI: 19.6-59.2%) were concordant for infection giving an estimated hereditability of 94.2%. Within these 37 twin pairs, factors such as primary or recurrent maternal infection, prematurity, growth discordance, and sex are described; however, in many of these cases these factors are unknown.
The rate of vertical transmission of congenital CMV is higher for twins than singletons. Discordance of congenital CMV in twins is not rare and suggests a possible genetic susceptibility to congenital CMV.
本研究旨在评估双胞胎与单胎妊娠相比垂直传播率的差异，评估双胞胎之间的不一致是否罕见，并描述单卵双胎和双卵双胎之间的一致性与遗传力的关系。
我们首先通过收集报告了单胎和双胎妊娠垂直传播的先天性巨细胞病毒（congenital cytomegalovirus，CMV）感染队列研究，以估计双胞胎中先天性 CMV 垂直传播率。这也使我们能够比较单胎和双胎的感染率。根据上述研究和其他先天性感染婴儿的大型队列，确定不一致感染的双胞胎比例是否为罕见现象。如果推测不一致并不罕见，我们将根据双胞胎是单卵双胎还是双卵双胎，分析先天性 CMV 感染的双胞胎病例数据，并计算相应的一致性率以估计广义遗传力。最后，我们描述了可能影响垂直传播的其他因素。
从五篇关注高危妊娠的文章中，双胎妊娠的垂直传播率为 58.7%（95%CI 43.3-72.3%），而单胎妊娠的垂直传播率为 31.4%（95%CI：29.0-34.0%）（P=0.0002）。在十项先天性 CMV 感染婴儿大型队列研究中，42 对至少有一胎感染的双胞胎中有 21 对不一致（50.0%，95%CI：34.4-65.6%），表明双胞胎中先天性 CMV 感染的不一致并不罕见。在涵盖至少有一胎患有先天性 CMV 且明确了双胎类型的 28 项研究中，13 对单卵双胎中有 11 对（84.6%，95%CI：53.7-97.3%）感染一致，24 对双卵双胎中有 9 对（37.5%，95%CI：19.6-59.2%）感染一致，估计遗传力为 94.2%。在这 37 对双胞胎中，描述了原发性或复发性母体感染、早产、生长不一致和性别等因素，但在许多情况下，这些因素并不清楚。
与单胎妊娠相比，双胞胎的先天性 CMV 垂直传播率更高。双胞胎中先天性 CMV 的不一致并不罕见，提示先天性 CMV 可能存在遗传易感性。
