Congenital limb reduction defects in 1.6 million births in Argentina

Prevalence, infant outcomes and gestational risk factors for transverse reduction deficiencies at or above the wrist: a population-based study

We identified individuals born in Norway between 1970 and 2019 with transverse reduction deficiency at or above the wrist (TRDAW) from the Medical Birth Registry of Norway and from the CULA (congenital upper limb anomaly) North Oslo Registry. Infant outcomes and parental factors were compared for 202 individuals with TRDAW to 2,741,013 living individuals without TRDAW born during the same period. We found an overall TRDAW prevalence of 0.74/10,000. Infants with TRDAW had a higher risk for being small for gestational age, an Apgar score <7 and transfer to neonatal intensive care units after delivery. Nine of the infants with TRDAW had associated anomalies, most commonly in the lower limb, and at a higher proportion than the reference population. Other than twin pregnancies, we are unable to identify with certainty any other risk factors for TRDAW.Level of evidence: I.

Update from a cohort study for birth defects in Hunan Province, China, 2010-2020

To define the relationship between sex, residence, maternal age, and a broad range of birth defects by conducting a comprehensive cross-analysis based on up-to-date data. Data were obtained from the Birth Defects Surveillance System in Hunan Province, China, 2010-2020. Prevalences of birth defects (number of cases per 10,000 fetuses (births and deaths at 28 weeks of gestation and beyond)) with 95% confidence intervals (CI) were calculated by sex, residence, maternal age, year, and 23 specific defects. Cross-analysis of sex, residence, and maternal age was conducted, and crude odds ratios (ORs) were calculated to examine the association of each maternal characteristic with birth defects. A total of 1,619,376 fetuses and 30,596 birth defects were identified. The prevalence of birth defects was 188.94/10,000 (95% CI 186.82-191.05). Birth defects were more frequent in males than females (210.46 vs. 163.03/10,000, OR = 1.30, 95% CI 1.27-1.33), in urban areas than in rural areas (223.61 vs. 162.90/10,000, OR = 1.38, 95% CI 1.35-1.41), and in mothers ≥ 35 than mothers 25-29 (206.35 vs. 187.79/10,000, OR = 1.10, 95% CI 1.06-1.14). Cross-analysis showed that the prevalence of birth defects was higher in urban females than in rural males (194.53 vs. 182.25/10,000), the difference in prevalence between males and females was more significant for maternal age < 20 compared to other age groups (OR = 1.64, 95% CI 1.37-1.95), and the prevalence difference between urban and rural areas is more significant for maternal age 25-34 compared to other age groups (OR = 1.49, 95% CI 1.43-1.57). Cleft palates were more frequent in males, and nine specific defects were more frequent in females. Five specific defects were more frequent in rural areas, and eight were more frequent in urban areas. Compared to mothers 25-29, five specific defects were more frequent in mothers < 20, seven specific defects were more frequent in mothers 20-24, two specific defects were more frequent in mothers 30-34, and ten specific defects were more frequent in mothers ≥ 35. Our data indicate that sex, residence, and maternal age differences in the prevalences of birth defects and most specific defects are common. We have found some new epidemiological characteristics of birth defects using cross-analysis, such as residence is the determining factor for the prevalence of birth defects, the difference in prevalence between males and females was more significant for maternal age < 20 compared to other age groups, the prevalence difference between urban and rural areas is more significant for maternal age 25-34 compared to other age groups. And differences in the epidemiological characteristics of some specific defects from previous studies. Future studies should examine mechanisms. Our findings contributed to clinical counseling and advancing research on the risk factors for birth defects.

Spectrum of fetal limb anomalies

PURPOSE

Antenatal detection of limb anomalies is not uncommon, and pregnancies are usually terminated in view of the expected physical handicap. The aim of this retrospective observational study is to delineate the spectrum of fetal limb anomalies and provide evidence in support of complete postnatal evaluation in establishing recurrence risk.

METHODS

We present 54 cases of limb malformations detected antenatally and discuss the spectrum of abnormalities, the utility of fetal autopsy, and genetic testing to establish recurrence risk in subsequent pregnancies.

RESULTS

16/54 cases were isolated radial ray anomalies. There were five cases of amniotic band syndrome, five limb body wall complex cases, three VACTERL (vertebral defects, anal atresia, cardiac defects, tracheo-esophageal fistula, renal anomalies, and limb abnormalities) associations, one case of sirenomelia, two cases of limb pelvis hypoplasia, and one case of OEIS (Omphalocele Exstrophy Imperforate anus and spinal defects). Four fetuses with non-isolated radial ray anomaly had trisomy 18. One case with bilateral radial ray defect had a mutation in the FANC-E gene confirming fanconi anemia. Twelve cases were unclassified.

CONCLUSION

Autopsy is the most important investigation in fetuses with limb anomalies. We suggest chromosomal microarray (CMA) as a first-tier test after autopsy. However, in cases of bilaterally symmetrical limb anomalies, in case of previous similarly affected child, or history of consanguinity, whole exome sequencing (WES) can be offered as the primary investigation, followed by CMA if WES is normal.

Etiological diagnosis in limb reduction defects and the number of affected limbs: A population-based study in the Northern Netherlands

Limb reduction defects (LRDs) that affect multiple limbs are considered to be more often heritable, but only few studies have substantiated this. We aimed to investigate if an etiological diagnosis (genetic disorder or clinically recognizable disorder) is more likely to be made when multiple limbs are affected compared to when only one limb is affected. We used data from EUROCAT Northern Netherlands and included 391 fetuses and children with LRDs born in 1981–2017. Cases were classified as having a transverse, longitudinal (preaxial/postaxial/central/mixed), intercalary, or complex LRD of one or more limbs and as having an isolated LRD or multiple congenital anomalies (MCA). We calculated the probability of obtaining an etiological diagnosis in cases with multiple affected limbs versus one affected limb using relative risk (RR) scores and Fisher's exact test. We showed that an etiological diagnosis was made three times more often when an LRD occurred in multiple limbs compared to when it occurred in one limb (RR 2.9, 95% CI 2.2–3.8, p < 0.001). No genetic disorders were found in isolated cases with only one affected limb, whereas a genetic disorder was identified in 16% of MCA cases with one affected limb. A clinically recognizable disorder was found in 47% of MCA cases with one affected limb. Genetic counseling rates were similar. We conclude that reduction defects of multiple limbs are indeed more often heritable. Genetic testing seems less useful in isolated cases with one affected limb, but is warranted in MCA cases with one affected limb.