Congenital diaphragmatic hernia and a complex heart defect in association with Wolf-Hirschhorn syndrome

Prenatal sonographic findings in confirmed cases of Wolf-Hirschhorn syndrome

Background

Wolf-Hirschhorn syndrome (WHS) is a common genetic condition and prenatal diagnosis is difficult due to heterogeneous expression of this syndrome and rather non-specific ultrasound findings. Objective of this study was to examine the prenatal ultrasound findings in fetuses with Wolf-Hirschhorn syndrome (WHS).

Methods

Retrospective assessment of 18 pregnancies that were seen at three tertiary referral centers (Universities of Bonn, Tuebingen and Nuernberg / Germany). Findings of prenatal ultrasound examinations, genetic results and outcome were compared. Additionally, findings of our study were compared to previous small case series from the literature and then compared to data on postnatal frequencies and abnormalities in affected patients.

Results

Median gestational age at the time of examination was 23 + 1 weeks’ (range: 13 + 4 to 29 + 1 weeks’) with female-to-male ratio of > 2.5:1. Most frequent ultrasound findings were facial abnormalities, symmetric IUGR and microcephaly that presented in 94.4, 83.3 and 72.2% of cases, respectively. The combination of microcephaly and hypoplastic nasal bone was a particularly characteristic finding. Growth retardation presented in all fetuses > 20 weeks, but not below. Other frequent abnormalities included cardiac anomalies in 50 and single umbilical artery (SUA) in 44.4% of fetuses.

Conclusion

WHS should be considered in the presence of symmetric IUGR together with microcephaly, hypoplastic nasal bone and facial abnormalities on prenatal ultrasound. Genetic testing by chromosomal microarray analysis (CMA) is strongly recommended in this context.

Genetic Diagnostic Strategies and Counseling for Families Affected by Congenital Diaphragmatic Hernia

Congenital diaphragmatic hernia (CDH) is a relatively common and severe birth defect with variable clinical outcome and associated malformations in up to 60% of patients. Mortality and morbidity remain high despite advances in pre-, intra-, and postnatal management. We review the current literature and give an overview about the genetics of CDH to provide guidelines for clinicians with respect to genetic diagnostics and counseling for families. Until recently, the common practice was (molecular) karyotyping or chromosome microarray if the CDH diagnosis is made prenatally with a 10% diagnostic yield. Undiagnosed patients can be reflexed to trio exome/genome sequencing with an additional diagnostic yield of 10 to 20%. Even with a genetic diagnosis, there can be a range of clinical outcomes. All families with a child with CDH with or without additional malformations should be offered genetic counseling and testing in a family-based trio approach.

The Role of De Novo Variants in Patients with Congenital Diaphragmatic Hernia

The genetic etiology of congenital diaphragmatic hernia (CDH), a common and severe birth defect, is still incompletely understood. Chromosomal aneuploidies, copy number variations (CNVs), and variants in a large panel of CDH-associated genes, both de novo and inherited, have been described. Due to impaired reproductive fitness, especially of syndromic CDH patients, and still significant mortality rates, the contribution of de novo variants to the genetic background of CDH is assumed to be high. This assumption is supported by the relatively low recurrence rate among siblings. Advantages in high-throughput genome-wide genotyping and sequencing methods have recently facilitated the detection of de novo variants in CDH. This review gives an overview of the known de novo disease-causing variants in CDH patients.

Evidence that FGFRL1 contributes to congenital diaphragmatic hernia development in humans

Fibroblast growth factor receptor-like 1 (FGFRL1) encodes a transmembrane protein that is related to fibroblast growth factor receptors but lacks an intercellular tyrosine kinase domain. in vitro studies suggest that FGFRL1 inhibits cell proliferation and promotes cell differentiation and cell adhesion. Mice that lack FGFRL1 die shortly after birth from respiratory distress and have abnormally thin diaphragms whose muscular hypoplasia allows the liver to protrude into the thoracic cavity. Haploinsufficiency of FGFRL1 has been hypothesized to contribute to the development of congenital diaphragmatic hernia (CDH) associated with Wolf-Hirschhorn syndrome. However, data from both humans and mice suggest that disruption of one copy of FGFRL1 alone is insufficient to cause diaphragm defects. Here we report a female fetus with CDH whose 4p16.3 deletion allows us to refine the Wolf-Hirschhorn syndrome CDH critical region to an approximately 1.9 Mb region that contains FGFRL1. We also report a male infant with isolated left-sided diaphragm agenesis who carried compound heterozygous missense variants in FGFRL1. These cases provide additional evidence that deleterious FGFRL1 variants may contribute to the development of CDH in humans.

Clinical and genetic characterization of ten Egyptian patients with Wolf-Hirschhorn syndrome and review of literature

Background

Wolf–Hirschhorn syndrome (WHS) (OMIM 194190) is a multiple congenital anomalies/intellectual disability syndrome. It is caused by partial loss of genetic material from the distal portion of the short arm of chromosome.

Methods

We studied the phenotype–genotype correlation.

Results

We present the clinical manifestations and cytogenetic results of 10 unrelated Egyptian patients with 4p deletions. Karyotyping, FISH and MLPA was performed for screening for microdeletion syndromes. Array CGH was done for two patients. All patients exhibited the cardinal clinical manifestation of WHS. FISH proved deletion of the specific WHS locus in all patients. MLPA detected microdeletion of the specific locus in two patients with normal karyotypes, while array CGH, performed for two patients, has delineated the extent of the deleted segments and the involved genes. LETM1, the main candidate gene for the seizure phenotype, was found deleted in the two patients tested by array CGH; nevertheless, one of them did not manifest seizures. The study emphasized the previous.

Conclusion

WHS is a contiguous gene syndrome resulting from hemizygosity of the terminal 2 Mb of 4p16.3 region. The Branchial fistula, detected in one of our patients is a new finding that, to our knowledge, was not reported.

Prioritization of Candidate Genes for Congenital Diaphragmatic Hernia in a Critical Region on Chromosome 4p16 using a Machine-Learning Algorithm

Wolf-Hirschhorn syndrome (WHS) is caused by partial deletion of the short arm of chromosome 4 and is characterized by dysmorphic facies, congenital heart defects, intellectual/developmental disability, and increased risk for congenital diaphragmatic hernia (CDH). In this report, we describe a stillborn girl with WHS and a large CDH. A literature review revealed 15 cases of WHS with CDH, which overlap a 2.3-Mb CDH critical region. We applied a machine-learning algorithm that integrates large-scale genomic knowledge to genes within the 4p16.3 CDH critical region and identified FGFRL1 , CTBP1 , NSD2 , FGFR3 , CPLX1 , MAEA , CTBP1-AS2 , and ZNF141 as genes whose haploinsufficiency may contribute to the development of CDH.

Proposal for standardized prenatal ultrasound assessment of the fetus with congenital diaphragmatic hernia by the European reference network on rare inherited and congenital anomalies (ERNICA)

Congenital diaphragmatic hernia is a rare disease associated with high mortality and morbidity. Antenatal ultrasound screening identifies more than 70% of cases, providing the opportunity for in utero referral to a tertiary care center for expert assessment and perinatal management. Additional genetic and morphologic assessment may be used to rule out associated anomalies. In isolated cases, the outcome may be predicted prenatally by medical imaging. The combination of lung size and liver herniation is a widely accepted method to stratify fetuses into groups with an increasing degree of pulmonary hypoplasia and corresponding mortality rates. Ultrasound measurement of the observed to expected lung-to-head ratio (o/e LHR) is most widely used. The o/e LHR is an independent predictor of survival and short-term morbidity. Finally, evaluation of stomach position has recently been introduced as an indirect method to estimate severity of the disease in left-sided defects, as it has been shown to correlate with the proportion of intrathoracic liver. Herein, we propose a protocol for the standardized ultrasound assessment of fetuses with isolated CDH and individualized prediction of neonatal outcome.

Prenatal diagnosis of Wolf-Hirschhorn syndrome: from ultrasound findings, diagnostic technology to genetic counseling

PURPOSE

Wolf-Hirschhorn syndrome (WHS) is a contiguous gene syndrome due to terminal chromosome 4p deletions. We explored prenatal diagnosis of WHS by ultrasound as well as karyotype and single nucleotide polymorphism array (SNP array) to characterize the structural variants of WHS prenatally.

METHODS

Ten prenatal cases of WHS were evaluated for the indication of the invasive testing, the ultrasound features, and cytogenetic and microarray results.

RESULTS

Eight cases were diagnosed by karyotyping and SNP array, while two cases were detected only by SNP array. Combining our cases with 37 prenatal cases from the literature, the most common sonographic features were IUGR (97.7%) and typical facial appearance (82.9%). Other less common phenotypes included renal hypoplasia (36.2%), cardiac malformation (29.8%), cleft lip and palate (25.5%), cerebral abnormalities (25.5%), skeletal anomalies (21.3%), and increased nuchal translucency/nuchal fold thickness (NT/NF) (19%).

CONCLUSIONS

The most common intrauterine phenotypes of WHS were severe IUGR and typical facial appearance with other less consistent ultrasound findings. Noninvasive prenatal testing (NIPT) is one very promising screening tool for WHS. SNP array can improve diagnostic precision for detecting WHS, especially for the cryptic aberrations that cannot be identified by the traditional karyotyping. Ectopic kidney may be a previously unrecognized phenotype of WHS.

CHD associated with syndromic diagnoses: peri-operative risk factors and early outcomes

CHD is frequently associated with a genetic syndrome. These syndromes often present specific cardiovascular and non-cardiovascular co-morbidities that confer significant peri-operative risks affecting multiple organ systems. Although surgical outcomes have improved over time, these co-morbidities continue to contribute substantially to poor peri-operative mortality and morbidity outcomes. Peri-operative morbidity may have long-standing ramifications on neurodevelopment and overall health. Recognising the cardiovascular and non-cardiovascular risks associated with specific syndromic diagnoses will facilitate expectant management, early detection of clinical problems, and improved outcomes--for example, the development of syndrome-based protocols for peri-operative evaluation and prophylactic actions may improve outcomes for the more frequently encountered syndromes such as 22q11 deletion syndrome.

A case of Wolf-Hirschhorn syndrome and hypoplastic left heart syndrome

Wolf-Hirschhorn Syndrome (WHS) is a genetic syndrome that includes a typical facial appearance, mental retardation, growth delay, seizures, and congenital cardiac defects. A deletion of the terminal band of the short arm of chromosome 4, with a breakpoint at the 4p15 to 4p16 region, is the most common genetic mutation causing WHS. Congenital heart disease associated with WHS typically includes atrial and ventricular septal defects, though there are a few case reports of associated complex congenital heart disease. Here we report a case of an infant with a large 4p deletion, with a breakpoint at the 4p12 region, and hypoplasic left heart syndrome. We discuss a possible link between the size of the chromosomal deletion in WHS and the severity of the cardiac defect.

Development of the diaphragm -- a skeletal muscle essential for mammalian respiration

The mammalian diaphragm muscle is essential for respiration, and thus is one of the most critical skeletal muscles in the human body. Defects in diaphragm development leading to congenital diaphragmatic hernias (CDH) are common birth defects and result in severe morbidity or mortality. Given its functional importance and the frequency of congenital defects, an understanding of diaphragm development, both normally and during herniation, is important. We review current knowledge of the embryological origins of the diaphragm, diaphragm development and morphogenesis, as well as the genetic and developmental aetiology of diaphragm birth defects.