Maternal Chronic Disease and Congenital Anomalies of the Kidney and Urinary Tract in Offspring: A Japanese Cohort Study

Vitamin A Deficiency Disturbs Ret Expression and Induces Urinary Tract Developmental Abnormalities in Mice

INTRODUCTION

Moderate vitamin A levels during pregnancy are strongly related to normal embryonic development in both animal models and population studies. Abnormal development of urinary tract system is linked to either an excess or a shortage of vitamin A. The relationships among maternal vitamin A deficiency prior to conception, moderate vitamin A supplementation during pregnancy, and abnormal urinary system development in offspring are unclear.

METHODS

By creating preconception and preconception + pregnancy vitamin A insufficiency mouse models, we investigated whether moderate vitamin A treatment during pregnancy may reduce the prevalence of CAKUT and increase distant vitamin A levels in offspring, as well as any potential pathways involved.

RESULTS

We effectively established a prepregnancy vitamin A-deficient mouse model by providing a particular diet with or without vitamin A for 4 weeks. The offspring of the hypovitaminosis A model group presented a greater proportion of neonatal urinary tract developmental malformations. Abnormalities in ureteral bud emergence and key molecules during renal development, such as p-Plcγ and Ret, may be the primary causes of offspring development of CAKUT as a result of mothers' hypovitaminosis A. Normal vitamin A diets, on the other hand, may help mitigate the teratogenic consequences of prepregnancy hypovitaminosis A, as well as defects produced by ureteral budding and major molecular changes.

CONCLUSION

In contrast, the administration of normal vitamin A feeds during pregnancy may ameliorate the teratogenic effects of prepregnancy hypovitaminosis A to a certain extent and may also ameliorate the abnormalities associated with ureteral budding and key molecular changes.

Maternal and fetal risk factors for congenital anomalies of the kidney and urinary tract: a birth cohort study in urban China

BACKGROUND

Congenital anomalies of the kidney and urinary tract (CAKUT) are among the most common causes of kidney diseases in children. Previous studies on CAKUT etiologies have been predominantly focused on non-modifiable genetic risk factors. The existing nongenetic studies are limited by lack of comprehensive investigation of potentially modifiable risk factors and the inability to distinguish among various phenotypes of CAKUT. Therefore, this study aimed to comprehensively evaluate both maternal and fetal risk factors of CAKUT, sorted by disease phenotype.

METHODS

A prospective birth cohort study was conducted among 10,179 women who delivered a singleton live newborn in Lanzhou, China, between 2010 and 2012. Face-to-face interviews were conducted among the participants within 1-3 days after delivery using standard questionnaires to collect information on maternal demographics and characteristics. All newborns underwent postnatal renal ultrasonographic screening during their routine 1-month checkup. Clinical data, including birth outcomes and maternal complications, were confirmed by reviewing their medical records. Maternal and fetal risk factors were compared in children with and without CAKUT. Multivariable logistic regression analysis was performed to identify independent risk factors of CAKUT and their phenotypes, respectively.

RESULTS

A total of 489 (4.8%) cases of CAKUT were identified. Logistic regression revealed that maternal overweight (pre-pregnancy), gestational diabetes, preterm birth, and low birth weight were independent risk factors for CAKUT. Maternal overweight increased the risk of vesicoureteral reflux (VUR, odds ratio (OR) = 1.441, 95% confidence interval (CI) 1.010-2.057) and posterior urethral valves (PUV, OR = 1.868, 95% CI 1.074-3.249). Gestational diabetes increased the risk of ureteropelvic junction obstruction (UPJO, OR = 1.269; 95% CI 1.044-1.543) and posterior urethral valves (OR = 1.794; 95% CI 1.302-2.474). Preterm birth increased the risk of ureteropelvic junction obstruction (OR = 1.056; 95% CI 1.004-1.111).

CONCLUSIONS

Our study identified various risk factors associated with different CAKUT phenotypes, stressing the importance of separate analyses for each phenotype. Our findings may provide helpful guidance on developing targeted and effective CAKUT prevention programs in the future.

Genetic and Clinical Factors Influencing Congenital Anomalies of the Kidney and Urinary Tract in Children: Insights from Prenatal and Postnatal Assessments

Congenital anomalies of the kidney and urinary tract (CAKUT) significantly contribute to pediatric morbidity, often necessitating ureterorenal surgery. This study explored the relationship between genetic mutations, renal surgery requirements, and prenatal, postnatal, and parental risk factors in children with CAKUT. A retrospective analysis of 651 children diagnosed with CAKUT included patient demographics, parental risk factors, ultrasound findings, genetic mutations, and surgical incidence. Antenatal ultrasounds showed normal findings in 32.1%, hydronephrosis in 46.9%, and other abnormalities in 21% of cases. Surgical intervention correlated with higher hydronephrosis reduction than non-intervention. Genetic mutations were identified in 5.4% of cases, with 24.6% requiring surgery. Low neonatal birth weight (odds ratio [OR] = 0.98, p < 0.001), advanced maternal age (OR = 1.06, p < 0.001), and postnatal abnormal ultrasound findings (OR = 2.62, p < 0.001) were associated with increased genetic mutation risks. Antenatal hydronephrosis (OR = 3.85, p < 0.001) and postnatal urinary tract infections (OR = 4.85, p < 0.001) increased the likelihood of surgical intervention. Neonatal birth weight, maternal age, and postnatal ultrasound findings were identified as independent risk factors for genetic mutations, while no significant link was found between these genetic factors and the need for surgery. Surgical needs were associated with urinary tract infections and antenatal hydronephrosis, indicating that timely surgical intervention may benefit these patients.

Congenital anomalies of the kidney and urinary tract

Congenital Anomalies of the Kidney and Urinary Tract (CAKUT) refer to a range of conditions that affect the kidney and urinary tract. These anomalies can be severe, such as kidney agenesis, or milder, such as vesicoureteral reflux. CAKUT affects over 1% of live births and accounts for 40-50% of cases of chronic kidney failure in children. The pathogenesis of CAKUT is caused by various environmental, genetic, and epigenetic factors that disrupt normal nephrogenesis. Environmental factors that can lead to CAKUT include maternal diabetes, obesity, malnutrition, alcohol consumption, or medications affecting kidneys development. Genetic factors can cause an imbalance in the metanephros and the ureteric bud interaction. Defects in specific genes such as PAX2, TBX18, NRIP1, REX, SIX2, BMP4, and chromosome 17 cause CAKUT. Over 50 genes have been identified as the root cause of this condition, with monogenetic variants causing up to 20% of all cases. CAKUTs can be diagnosed through fetal ultrasonography, but some anomalies may remain undetected. GWASs, Next Generation Sequencing for targeted and whole exome DNA sequencing may provide additional diagnostic methods. This review article highlights some the leading factors that cause CAKUT, which adversely affects kidney development and urinary tract function.

Maternal diseases and congenital anomalies of the kidney and urinary tract in offspring: a cohort study

BACKGROUND

Congenital anomalies of the kidneys and urinary tract (CAKUT) are the most common cause of prenatally diagnosed developmental malformation. This study aimed to assess the relationship between maternal diseases and CAKUT in offspring.

METHODS

This retrospective study enrolled all pregnant women registered from January 2020 to December 2022 at one medical center. Medical information on maternal noncommunicable diseases, including obesity, hypertension, diabetes mellitus, kidney disease, hyperthyroidism, hypothyroidism, psychiatric disease, epilepsy, cancer, and autoimmune disease was collected. Based on the records of ultrasound scanning during the third trimester, the diagnosis was classified as isolated urinary tract dilation (UTD) or kidney anomalies. Multivariate logistic regression was performed to establish models to predict antenatal CAKUT.

RESULTS

Among the 19,656 pregnant women, perinatal ultrasound detected suspicious CAKUT in 114 (5.8/1000) fetuses, comprising 89 cases with isolated UTD and 25 cases with kidney anomalies. The risk of antenatal CAKUT was increased in the fetuses of mothers who experienced gestational diabetes, thyroid dysfunction, neuropsychiatric disease, anemia, ovarian and uterine disorders. A prediction model for isolated UTD was developed utilizing four confounding factors, namely gestational diabetes, gestational hypertension, maternal thyroid dysfunction, and hepatic disease. Similarly, a separate prediction model for kidney anomalies was established based on four distinct confounding factors, namely maternal thyroid dysfunction, gestational diabetes, disorders of ovarian/uterine, and kidney disease.

CONCLUSIONS

Isolated UTD and kidney anomalies were associated with different maternal diseases. The results may inform the clinical management of pregnancy and highlight potential differences in the genesis of various subtypes of CAKUT.

Maternal infection with hepatitis B virus before pregnancy and risk of congenital malformations in offspring: a record-linkage study of a large national sample from China

Background

Whether hepatitis B virus (HBV) infection of women prior to pregnancy can influence risk of congenital malformations in offspring remains controversial. We assessed the association between them by considering congenital malformations in the aggregate as well as risk of organs systems using a large national sample of Chinese women.

Methods

We performed a record-linkage cohort study of women who participated in National Free Preconception Health Examination Project, between January 1, 2010, and December 31, 2019 for whom data on congenital malformations in their offspring were available from the National Population-Based Birth Defects Surveillance Network. A total of 498,968 linked records were obtained, of which 127,371 were excluded because HBV status before pregnancy was unknown, the records involved multiple pregnancies, or pre-pregnancy examinations were conducted after conception. Based on pre-pregnancy status, mothers were assigned to two categories of HBsAg- or HBsAg+ and, in certain analyses, to three categories of HBsAg-, HBsAg+/HBeAg- or HBsAg+/HBeAg+. Potential associations of serological status with risk of congenital malformations, considered separately or in aggregate, were explored using multilevel logistic regression. Factors that might influence such associations were also explored.

Findings

Among the 371,597 women analyzed, 21,482 (5.78%) were HBsAg+ before pregnancy, and 8333 (2.24%) had a fetus or child diagnosed with congenital malformations, composed of 7744 HBsAg- women and 589 HBsAg+ women. HBsAg+ status was associated with increased risk of congenital malformations in the aggregate (OR 1.14, 95% CI 1.03-1.25) and of cardiovascular malformations specifically (OR 1.18, 95% CI 1.03-1.35). HBsAg+/HBeAg- status was associated with significantly higher risk of cardiovascular malformations (OR 1.19, 95% CI 1.01-1.39) as well as reproductive malformations (OR 1.51, 95% CI 1.02-2.23). Associations between HBsAg+ status before pregnancy and risk of congenital malformations was modified by alanine aminotransferase activity (P interaction < 0.05).

Interpretation

Prepregnancy HBV infection might be associated with fetal malformations. This association needs further investigation to confirm whether it is a causal association, and assess whether antiviral therapy of women with HBsAg+ planning to conceive might reduce the risk of fetal malformations.

Funding

The National Health Commission of the People's Republic of China, China; Science and Technology Department of Sichuan Province, China; and the Ministry of Science and Technology of the People's Republic of China.

The genetics and pathogenesis of CAKUT

Congenital anomalies of the kidney and urinary tract (CAKUT) comprise a large variety of malformations that arise from defective kidney or urinary tract development and frequently lead to kidney failure. The clinical spectrum ranges from severe malformations, such as renal agenesis, to potentially milder manifestations, such as vesicoureteral reflux. Almost 50% of cases of chronic kidney disease that manifest within the first three decades of life are caused by CAKUT. Evidence suggests that a large number of CAKUT are genetic in origin. To date, mutations in ~54 genes have been identified as monogenic causes of CAKUT, contributing to 12-20% of the aetiology of the disease. Pathogenic copy number variants have also been shown to cause CAKUT and can be detected in 4-11% of patients. Furthermore, environmental and epigenetic factors can increase the risk of CAKUT. The discovery of novel CAKUT-causing genes is challenging owing to variable expressivity, incomplete penetrance and variable genotype-phenotype correlation. However, such a discovery could ultimately lead to improvements in the accurate molecular genetic diagnosis, assessment of prognosis and multidisciplinary clinical management of patients with CAKUT, potentially including personalized therapeutic approaches.

Congenital Anomalies of the Kidney and Urinary Tract: A Continuum of Care

Congenital anomalies of the kidney and urinary tract (CAKUT) are the leading cause of kidney failure in children and adolescents. CAKUT describes a wide spectrum of structural disorders with a prenatal origin. The etiology of CAKUT is multifactorial, including environmental, nongenetic, and genetic causes that impact kidney development as well as upper and lower urinary tract development. Adult nephrologists who treat patients with CAKUT may be challenged by the underlying diseases they are not familiar with and the accumulation of chronic kidney disease complications in childhood. This article discusses CAKUT etiology and presentation, the course during childhood and adolescence, as well as adult issues in CAKUT patients including CKD complications, urologic interventions, and genetic counseling. A smooth transition of CAKUT patients from pediatric to adult care can be challenging. Semin Nephrol 43:x-xx © 2023 Elsevier Inc. All rights reserved.