Prenatal diagnosis of Jeune-like syndromes with two-dimensional and three-dimensional sonography

Spectrum of congenital anomalies of the kidney and urinary tract (CAKUT) including renal parenchymal malformations during fetal life and the implementation of prenatal exome sequencing (WES)

OBJECTIVES AND BACKGROUND

Congenital malformations of the kidney and urinary tract (CAKUT) have a prevalence of 4-60 in 10,000 livebirths and constitute for 40-50% of all end stage pediatric kidney disease. CAKUT can have a genetic background due to monogenetic inherited disease, such as PKD or ciliopathies. They can also be found in combination with extra-renal findings as part of a syndrome. Upon detection of genitourinary malformations during the fetal anomaly scan the question arises if further genetic testing is required. The purpose of this study was to determine the phenotypic presentation of CAKUT cases and the results of exome analysis (WES).

METHODS

This is a retrospective analysis of 63 fetal cases with a diagnosis of CAKUT or DSD at a single center between August 2018 and December 2022.

RESULTS

A total of 63 cases (5.6%) out of 1123 matched CAKUT phenotypes including renal parenchyma malformations. In 15 out of 63 WES analysis a pathogenic variant was detected (23.8%). In fetuses with isolated CAKUT the rate of detecting a pathogenic variant on exome sequencing was five out of 44 (11.4%). Ten out of 19 fetuses (52.6%) that displayed extra-renal findings in combination with CAKUT were diagnosed with a pathogenic variant.

CONCLUSIONS

WES provides an increase in diagnosing pathogenic variants in cases of prenatally detected CAKUT. Especially in fetuses with extra-renal malformations, WES facilitates a gain in information on the fetal genotype to enhance prenatal counselling and management.

Fetal ciliopathies: a retrospective observational single-center study

Purpose

Report on the diagnosis of prenatally suspected multisystem ciliopathies in a single center between 2002 and 2020.

Methods

Retrospective observational single-center study including pregnancies with prenatal ultrasound features of multisystem ciliopathies, such as hyperechogenic kidneys together with polydactyly and/or other skeletal and extraskeletal findings. Cases were compared according to their prenatal findings and outcomes.

Results

36 cases of multisystem ciliopathies were diagnosed. Meckel-Gruber syndrome (MKS) was the most common ciliopathy (n = 19/36, 52.8%), followed by disorders that belong to the group of short-rib thoracic dysplasia (SRTD, n = 10/36, 27.8%) McKusick–Kaufmann syndrome (MKKS, n = 4/36, 11.1%), Bardet–Biedl syndrome (BBS, n = 2/36, 5.5%) and Joubert syndrome (n = 1/36, 2.8%). All cases showed abnormalities of the kidneys, most often hyperechogenic parenchyma (n = 26/36, 72.2%), cystic dysplasia (n = 24/36, 66.7%), and/or bilateral kidney enlargement (n = 22/36, 61.1%). Oligohydramnios was mainly present in fetuses with MKS. Polydactyly (n = 18/36), abnormalities of the CNS (n = 25/36), and heart defects (n = 10/36) were associated in 50%, 69.4%, and 27.8%, respectively.

Conclusion

Prenatal detection of renal abnormalities associated with skeletal or brain abnormalities should raise the suspicion for multisystem ciliopathies. Prenatal ultrasound can help to differentiate between different diseases and pave the way for subsequent targeted genetic testing.

Prenatal genetic considerations of congenital anomalies of the kidney and urinary tract (CAKUT)

Congenital anomalies of the kidney and urinary tract (CAKUT) constitute 20% of all congenital malformations occurring in one in 500 live births. Worldwide, CAKUT are responsible for 40% to 50% of pediatric and 7% of adult end-stage renal disease. Pathogenic variants in genes causing CAKUT include monogenic diseases such as polycystic kidney disease and ciliopathies, as well as syndromes that include isolated kidney disease in conjunction with other abnormalities. Prenatal diagnosis most often occurs using ultrasonography; however, further genetic diagnosis may be made using a variety of testing strategies. Family history and pathologic examination can also provide information to improve the ability to make a prenatal diagnosis of CAKUT. Here, we provide a comprehensive overview of genetic considerations in the prenatal diagnosis of CAKUT disorders. Specifically, we discuss monogenic causes of CAKUT, associated ultrasound characteristics, and considerations for genetic diagnosis, antenatal care, and postnatal care.

Jeune syndrome: considerations for management of asphyxiating thoracic dystrophy

Jeune syndrome (JS), or asphyxiating thoracic dystrophy, is a rare genetic disorder characterized by a small, narrow thorax, with associated shortening of limbs. Children with JS present with variable degrees of respiratory distress, frequently lethal in the neonatal period. Other associated complications include renal, hepatic, gastrointestinal, and retinal dysfunction. Management focuses on stabilization and support of respiratory function. Treatment may be palliative in nature or corrective. In recent years, the advance in surgical treatment of the thoracic hypoplasia in JS offers hope to those families with a child suffering from the syndrome. Even with increased research into treatment of this disorder, prognosis is usually poor. Comorbidities associated with JS lead to serious organ dysfunction in later years. Families who have a child with JS need genetic counseling and education focusing on the seriousness of the disorder, the risks and benefits of treatment, and the lifelong needs of those with JS.