Genetic diagnosis of common fetal renal abnormalities detected on prenatal ultrasound

Genetic and environmental factors driving congenital solitary functioning kidney

BACKGROUND

Congenital solitary functioning kidney (CSFK) is an anomaly predisposing to hypertension, albuminuria and chronic kidney disease. Its aetiology is complex and includes genetic and environmental factors. The role of gene-environment interactions (G×E), although relevant for other congenital anomalies, has not yet been investigated. Therefore, we performed a genome-wide G×E analysis with six preselected environmental factors to explore the role of these interactions in the aetiology of CSFK.

METHODS

In the AGORA (Aetiologic research into Genetic and Occupational/environmental Risk factors for Anomalies in children) data- and biobank, genome-wide single-nucleotide variant (SNV) data and questionnaire data on prenatal exposure to environmental risk factors were available for 381 CSFK patients and 598 healthy controls. Using a two-step strategy, we first selected independent significant SNVs associated with one of the six environmental risk factors. These SNVs were subsequently tested in G×E analyses using logistic regression models, with Bonferroni-corrected P-value thresholds based on the number of SNVs selected in step one.

RESULTS

In step one, 7-40 SNVs were selected per environmental factor, of which only rs3098698 reached statistical significance (P = .0016, Bonferroni-corrected threshold 0.0045) for interaction in step two. The interaction between maternal overweight and this SNV, which results in lower expression of the Arylsulfatase B (ARSB) gene, could be explained by lower insulin receptor activity in children heterozygous for rs3098698. Eight other G×E interactions had a P-value <.05, of which two were biologically plausible and warrant further study.

CONCLUSIONS

Interactions between genetic and environmental factors may contribute to the aetiology of CSFK. To better determine their role, large studies combining data on genetic and environmental risk factors are warranted.

Prenatal diagnosis of polycystic renal diseases: diagnostic yield, novel disease-causing variants, and genotype-phenotype correlations

BACKGROUND

Polycystic renal disease is a frequent congenital anomaly of the kidneys, but research using chromosomal microarray analysis and exome sequencing in fetuses with polycystic renal disease remains sparse, with most studies focusing on the multisystem or genitourinary system.

OBJECTIVE

This study aimed to assess the detection rate of detectable genetic causes of fetal polycystic renal disease at different levels, novel disease-causing variants, and genotype-phenotype correlations.

STUDY DESIGN

This study included 220 fetal polycystic renal disease cases from January 2014 to June 2022. Cases were divided into the following 3 groups: isolated multicystic dysplastic kidneys, nonisolated multicystic dysplastic kidneys, and suspected polycystic kidney disease group. We reviewed data on maternal demographics, ultrasonographic results, chromosomal microarray analysis/exome sequencing results, and pregnancy outcomes.

RESULTS

In our cohort, chromosomal microarray analysis identified 19 (8.6%) fetuses carrying chromosomal abnormalities, and the most common copy number variation was 17q12 microdeletion (7/220; 3.2%). Furthermore, 94 families chose to perform trio-exome sequencing testing, and 21 fetuses (22.3%) were found to harbor pathogenic/likely pathogenic variants. There was a significant difference in the live birth rate among the 3 groups (91/130 vs 46/80 vs 1/10; P<.001). Among 138 live birth cases, 106 (78.5%) underwent postnatal ultrasound review, of which 95 (89.6%) had a consistent prenatal-postnatal ultrasound diagnosis.

CONCLUSION

For both isolated and nonisolated polycystic renal disease, our data showed high detection efficiency with both testing tools. The detection of novel pathogenic variants expands the known disease spectrum of polycystic renal disease-associated genes while enriching our understanding of the genotype-phenotype correlation. Therefore, we consider it feasible to perform chromosomal microarray analysis+exome sequencing testing in fetal polycystic renal disease. Moreover, prenatal-postnatal ultrasound concordance was greater, the live birth rate was higher, and prognosis was better when known genetic disorders were excluded, indicating that genetic testing results significantly influenced pregnancy decisions.

A meta-analysis of pregnancy outcomes in the diagnosis of isolated foetal renal parenchyma by prenatal ultrasonography

BACKGROUND

To effectively circumvent foetal structural abnormalities and serious newborn sequelae, antenatal ultrasound evaluation can support making an early diagnosis for potential prenatal management or the termination of pregnancy.

OBJECTIVE

This study systematically evaluated a meta-analysis of different pregnancy outcomes in the diagnosis of isolated foetal renal parenchymal echogenicity (IHEK) by prenatal ultrasonography.

METHODS

Two researchers conducted a literature search following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The following databases were included in the search: China National Knowledge Infrastructure, Wanfang Medical Network, China Academic Journals Full-text Database, PubMed, Web Of Science and Springer Link; additional library websites were also included, and the search reviewed different pregnancies among patients with IHEK. The outcome indicators were the live birth rate, the incidence of polycystic renal dysplasia and the incidence of pregnancy termination/neonatal death. The meta-analysis was performed using the Stata/SE 12.0 software.

RESULTS

A total of 14 studies were included in the meta-analysis (total sample content, 1,115 cases). The combined effect size of prenatal ultrasound diagnosis of pregnancy termination/neonatal mortality in patients with IHEK was 0.289 (confidence interval (CI) 95%; range, 0.102-0.397). The combined effect size of the live birth rate of pregnancy outcomes was 0.742 (CI 95%; range, 0.634-0.850. The combined effect size of the polycystic kidney dysplasia rate was 0.066 (CI 95%; range, 0.030-0.102). The heterogeneity of all three results was > 50%; accordingly, a random-effects model was used.

CONCLUSION

The indications for eugenic labour should not be included in a prenatal ultrasound diagnosis of patients with IHEK. In the results of this meta-analysis, the live birth and polycystic dysplasia rates were optimistic in terms of pregnancy outcomes. Therefore, under the condition of excluding other unfavourable factors, it is necessary to A thorough technical inspection is required to make an accurate judgment.

A Genome-Wide Association Study into the Aetiology of Congenital Solitary Functioning Kidney

Congenital solitary functioning kidney (CSFK) is a birth defect that occurs in 1:1500 children and predisposes them to kidney injury. Its aetiology is likely multifactorial. In addition to known monogenic causes and environmental risk factors, common genetic variation may contribute to susceptibility to CSFK. We performed a genome-wide association study among 452 patients with CSFK and two control groups of 669 healthy children and 5363 unaffected adults. Variants in two loci reached the genome-wide significance threshold of 5 × 10-8, and variants in 30 loci reached the suggestive significance threshold of 1 × 10-5. Of these, an identified locus with lead single nucleotide variant (SNV) rs140804918 (odds ratio 3.1, p-value = 1.4 × 10-8) on chromosome 7 was most promising due to its close proximity to HGF, a gene known to be involved in kidney development. Based on their known molecular functions, both KCTD20 and STK38 could explain the suggestive significant association with lead SNV rs148413365 on chromosome 6. Our findings need replication in an independent cohort of CSFK patients before they can be established definitively. However, our analysis suggests that common variants play a role in CSFK aetiology. Future research could enhance our understanding of the molecular mechanisms involved.