Congenital diaphragmatic hernia (CDH) is a relatively common birth defect associated with high mortality and morbidity. Although the exact etiology of most cases of CDH remains unknown, there is a growing body of evidence that genetic factors play an important role in the development of CDH. In this review, we examine key findings that are likely to form the basis for future research in this field. Specific topics include a short overview of normal and abnormal diaphragm development, a discussion of syndromic forms of CDH, a detailed review of chromosomal regions recurrently altered in CDH, a description of the retinoid hypothesis of CDH, and evidence of the roles of specific genes in the development of CDH.

Congenital diaphragmatic hernia (CDH) has an incidence of 1 in 3,000 births and a high mortality rate (33%-58%). Multifactorial inheritance, teratogenic agents, and genetic abnormalities have all been suggested as possible etiologic factors. To define candidate regions for CDH, we analyzed cytogenetic data collected on 200 CDH cases, of which 7% and 5% showed numerical and structural abnormalities, respectively. This study focused on the most frequent structural anomaly found: a deletion on chromosome 15q. We analyzed material from three of our patients and from four previously published patients with CDH and a 15q deletion. By using array-based comparative genomic hybridization and fluorescent in situ hybridization to determine the boundaries of the deletions and by including data from two individuals with terminal 15q deletions but without CDH, we were able to exclude a substantial portion of the telomeric region from the genetic etiology of this disorder. Moreover, one patient with CDH harbored a small interstitial deletion. Together, these findings allowed us to define a minimal deletion region of approximately 5 Mb at chromosome 15q26.1-26.2. The region contains four known genes, of which two--NR2F2 and CHD2--are particularly intriguing gene candidates for CDH.

Non-isolated congenital diaphragmatic hernia (CDH+) is a severe birth defect that is often caused by de novo chromosomal anomalies. In this report, we use genome-wide oligonucleotide-based array comparative genome hybridization (aCGH) followed by rapid real-time quantitative PCR analysis to identify, confirm and map chromosomal anomalies in a cohort of 26 CDH+ patients. One hundred and five putative copy number changes were identified by aCGH in our cohort of CDH+ patients. Sixty-one of these changes (58%) had been previously described in normal controls. Twenty of the remaining 44 changes (45%) were confirmed by quantitative real-time PCR or standard cytogenetic techniques. These changes included de novo chromosomal abnormalities in five of the 26 patients (19%), two of whom had previously normal G-banded chromosome analyses. Data from these patients provide evidence for the existence of CDH-related genes on chromosomes 2q37, 6p22-25 and 14q, and refine the CDH minimal deleted region on 15q26 to an interval that contains COUP-TFII and only eight other known genes. Although COUP-TFII is likely to play a role in the development of CDH in patients with 15q26 deletions, we did not find COUP-TFII mutations in 73 CDH samples. We conclude that the combination of oligonucleotide-based aCGH and quantitative real-time PCR is an effective method of identifying, confirming and mapping clinically relevant copy number changes in patients with CDH+. This method is more sensitive than G-banded chromosome analysis and may find wide application in screening patients with congenital anomalies.

De novo monoallelic variants in NFIX cause two distinct syndromes. Whole gene deletions, nonsense variants and missense variants affecting the DNA-binding domain have been seen in association with a Sotos-like phenotype that we propose is referred to as Malan syndrome. Frameshift and splice-site variants thought to avoid nonsense-mediated RNA decay have been seen in Marshall-Smith syndrome. We report six additional patients with Malan syndrome and de novo NFIX deletions or sequence variants and review the 20 patients now reported. The phenotype is characterised by moderate postnatal overgrowth and macrocephaly. Median height and head circumference in childhood are 2.0 and 2.3 standard deviations (SD) above the mean, respectively. There is overlap of the facial phenotype with NSD1-positive Sotos syndrome in some cases including a prominent forehead, high anterior hairline, downslanting palpebral fissures and prominent chin. Neonatal feeding difficulties and/or hypotonia have been reported in 30% of patients. Developmental delay/learning disability have been reported in all cases and are typically moderate. Ocular phenotypes are common, including strabismus (65%), nystagmus (25% ) and optic disc pallor/hypoplasia (25%). Other recurrent features include pectus excavatum (40%) and scoliosis (25%). Eight reported patients have a deletion also encompassing CACNA1A, haploinsufficiency of which causes episodic ataxia type 2 or familial hemiplegic migraine. One previous case had episodic ataxia and one case we report has had cyclical vomiting responsive to pizotifen. In individuals with this contiguous gene deletion syndrome, awareness of possible later neurological manifestations is important, although their penetrance is not yet clear.

The overall objective of this guideline is to provide up-to-date, evidence-based recommendations for the diagnosis and surveillance of all symptoms in children and adults with either basal cell naevus syndrome (BCNS), a clinical suspicion of BCNS, or a parent with BCNS. In the last two groups, the guidelines should be followed until the diagnosis of BCNS can be rejected with certainty. The guideline aims to:• Update and expand on the previous guidelines by an appraisal of all relevant literature from January 2011 up to January 2021• Address important, practical, clinical questions relating to the primary guideline objective• Provide guideline recommendations • Discuss potential developments and future directions The guideline is presented as a detailed review with highlighted recommendations for practical use in the clinic by dermatologists and other healthcare professionals, including general practitioners, clinical geneticists, paediatricians, ophthalmologists, craniomaxillofacial surgeons, neurologists, cardiologists and psychologists. ExclusionsThe guideline does not cover therapeutic recommendations for (nondermatological) symptoms, as the guideline mainly focuses on screening and follow-up of symptoms. Therapeutic recommendations for basal cell carcinomas (BCCs) in general have been published in international BCC guidelines. 1,2 Stakeholder involvement and peer reviewThe guideline was developed at the Maastricht University Medical Centre (MUMC+), the Dutch BCNS expert centre accredited

With this review article, we aim to provide a concise overview of the current most important experimental genetic data available in the field of CDH.

Congenital diaphragmatic hernia (CDH) is a severe birth defect characterized by a defect in the diaphragm with pulmonary hypoplasia and postnatal pulmonary hypertension. Approximately 50% of CDH cases are associated with other non-pulmonary congenital anomalies (so called non-isolated CDH) and in 5-10% of cases there is a chromosomal etiology. The majority of CDH cases are detected prenatally. In some cases prenatal chromosome analysis reveals a causative chromosomal anomaly, most often aneuploidy. Deletion of 15q26 is the most frequently described structural chromosomal aberration in patients with non-isolated CDH. In this paper we report on two patients with a deletion of 15q26 and phenotypes similar to other patients with CDH caused by 15q26 deletions. This phenotype consists of intra-uterine growth retardation, left-sided CDH, cardiac anomalies and characteristic facial features, similar to those seen in Fryns syndrome. We propose that when this combination of birth defects is identified, either pre- or postnatally, further investigations to confirm or exclude a deletion of 15q26 are indicated, since the diagnosis of this deletion will have major consequences for the prognosis and, therefore, can affect decision making.

Congenital diaphragmatic hernia (CDH) is a relatively common birth defect with a high mortality. Although little is known about its etiology, there is increasing evidence for a strong genetic contribution. Both numerical and structural chromosomal abnormalities have been described in patients with CDH. Partial trisomy 11q and partial trisomy 22 associated with the common t(11;22) has been reported in several cases of CDH. It has been assumed that the diaphragmatic defect seen in these individuals was primarily due to duplication of material from chromosome 22q11. However, in this report we describe a family with a t(11;12) in which one of two brothers with partial trisomy 11q has a left sided posterolateral CDH. This is the second case of CDH in partial trisomy 11q due to an unbalanced translocation other than t(11;22). Using array-based comparative genomic hybridization and fluorescent in situ hybridization, we mapped the breakpoints in both brothers and their mother who is a balanced translocation carrier. Our results suggest that duplication of one or more genes on a approximately 19 Mb region of 11q23.3-qter predisposes to the development of CDH. These effects may be the primary cause of CDH in individuals t(11;22) or may be additive to effects from the duplication of chromosome 22 material. We also conclude that the partial trisomy 11q syndrome has a variable phenotype and that CDH should be added to the spectrum of anomalies that can be present in this syndrome.