Trisomy 2p: Analysis of unusual phenotypic findings

We present three probands with partial trisomies 2p21–23 due to ins(4;2)(q21;p21p23) pat, 2p23-pter due to t(2;4)(p23;q35)mat, and 2p21-pter due to t(2;11)(p21;q23.3)mat. More than 50 cases of partial trisomy 2p have been reviewed and some abnormalities, unusual for most other types of structural autosomal imbalance, have been found in patients with inherited forms of 2p trisomy and in their non-karyotyped sibs. Neural tube defects (anencephaly, occipital encephalocele, and spina bifida) were found in five probands and 4/6 affected non-karyotyped sibs. The only triplicated segment common to all was 2p24. Different forms of “broncho-pulmonary a/hypoplasia” (including two cases of lung agenesis) were described in four patients (overlapping triplicated segment was 2p21–p25). Three patients (with overlapping triplicated segment 2p23–p25) had diaphragmatic hernia. Abnormal rotation of the heart or L-transposition of large vessels (with or without visceral heterotaxia) was found in two infants (overlapping triplicated segment 2p23p24). In two patients with common triplicated segment 2p22.3–p25, neuroblastoma has been described. The occurrence of all these defects may be explained either by the action of the same gene(s) mapped to 2p24 or by action of some independent factors located in different segments of the short arm. Although the latter hypothesis is much less probable, it can not be rejected at the present time. We propose the existence of a genetic system controlling surveillance of an abnormal embryo to explain the phenotypic differences between patients with the same imbalance within a family. In some “restrictive” combinations the abnormal embryos will die, although in “permissive” combinations they can survive. © 1995 Wiley-Liss, Inc.     

Lung development following diaphragmatic hernia in the fetal rabbit

Diaphragmatic hernia was created in 39 rabbit fetuses on day 23 of gestation. Fifteen fetuses underwent a sham thoracotomy (SHAM). Thirty-nine non-operated littermates served as internal controls (CTR). Fetuses were harvested by Caesarean section on days 25, 27, 29 and 30 of gestation. Pulmonary response was evaluated by lung to body weight ratio (LBWR), morphometry, and density of type II pneumocytes. No difference was found between CTR and SHAM fetuses at term. CDH fetuses had smaller lungs (LBWR 0.014 +/- 0.004 versus 0.030 +/- 0.04 in CTR, P < 0.0001), a less complex acinus [mean terminal bronchial density (MTBD) 1.786 +/- 0.408 versus 0.917 +/- 0. 188, P < 0.0001], thicker alveolar septa [mean wall transection length (LMW) 0.0221 +/- 0.008 versus 0.0142 +/- 0.002, P = 0.0003], and a lower type II cell count (144.5 +/- 19.33 versus 216.2 +/- 27.85 per high power field, P < 0.0001). The differences in MTBD and LMW were significant from gestational day 25 onwards, and the differences in type II cell count from day 27 onwards. Surgical diaphragmatic hernia in rabbit fetuses in the late pseudoglandular phase reproduces many features of the pulmonary hypoplasia associated with human congenital diaphragmatic hernia, including the delayed maturation. The effects are present within 2 days following experimental diaphragmatic hernia and progress over time.     

Craniosynostoses: Phenotypic/molecular correlations

Fryns syndrome is an autosomal recessive multiple congenital anomaly syndrome characterized by diaphragmatic hernia, unusual facies, and distal limb hypoplasia. It was first reported as a lethal condition. We report on a three-year-old survivor with Fryns syndrome, and provide a review on the outcome of other survivors. Patients who survive the neonatal period represent 14% of reported cases. Characteristics of survivors include less frequent diaphragmatic hernia and milder lung hypoplasia, absence of complex cardiac malformation, and neurologic impairment. Multiple central nervous system abnormalities have been reported in Fryns syndrome, including agenesis of the corpus callosum, Dandy-Walker abnormality, cerebellar heterotopias, cerebellar hypoplasia, enlarged ventricles, and hypoplasia of the olfactory bulbs. Our patient exhibited profound mental retardation. He had malformations of gyration and sulcation, particularly around the central sulcus, and hypoplastic optic tracts beyond the optic chiasm. Understanding of long-term outcome of survivors is important for counseling of families with Fryns syndrome. Careful brain examination is advised; however, a normal radiological brain examination does not preclude developmental delay. The spectrum of individual outcome and of associated anomalies indicates that individual evaluation, imaging for structural brain malformation, is strongly advised. © 1995 Wiley-Liss, Inc.     

Endothelin receptor expression in human lungs of newborns with congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a major cause of refractory respiratory failure in the neonatal period and is characterized by persistent pulmonary hypertension of the newborn (PPHN) and pulmonary hypoplasia. Endothelin-1 (ET-1) dysregulation may play a significant role in the pathophysiology of PPHN and ET-1 acts through binding to type A (ETA) and type B (ETB) receptors. Therefore, ETA and ETB receptor protein expression was studied using immunohistochemistry in 10 lung specimens obtained from newborns with CDH, and 4 normal lung specimens, in order to explore whether dysregulation of ETA and ETB expression contributes to PPHN. ETA and ETB mRNAs were then quantified using real-time RT-PCR in laser-microdissected pulmonary resistive arteries. In the lungs of newborns with CDH, immunohistochemistry of both ETA and ETB receptors demonstrated over-expression in the thickened media of pulmonary arteries. Using laser microdissection and real-time RT-PCR, higher levels of ETA and ETB mRNA were found in CDH pulmonary arteries than in controls: this increase was more pronounced for ETA mRNA. This study provides the first demonstration of ET-1 receptor dysregulation in association with structural alteration of pulmonary arteries in newborns with CDH and PPHN. This dysregulation preferentially affects the ETA receptor. These results suggest that dysregulation of ET-1 receptors may contribute to PPHN associated with CDH.     

Factors other than genotype account largely for the phenotypic variation of the pulmonary valve in Syrian hamsters

Understanding of the aetiology of congenitally anomalous pulmonary valves remains incomplete. The aim of our study, therefore, was to elucidate the degree to which the phenotypic variation known to exist for the pulmonary valve relies on genotypic variation. Initially, we tested the hypothesis that genetically alike individuals would display similar valvar phenotypes if the phenotypic arrangement depended entirely, or almost entirely, on the genotype. Thus, we examined pulmonary valves from 982 Syrian hamsters belonging to two families subject to systematic inbreeding by crossing siblings. Their coefficient of inbreeding was 0.999 or higher, so they could be considered genetically alike. External environmental factors were standardized as much as possible. A further 97 Syrian hamsters from an outbred colony were used for comparative purposes. In both the inbred and outbred hamsters, we found valves with a purely trifoliate, or tricuspid, design, trifoliate valves with a more or less extensive fusion of the right and left leaflets, bifoliate, or bicuspid, valves with fused right and left leaflets, with or without a raphe located in the conjoined arterial sinus, and quadrifoliate, or quadricuspid, valves. The incidence of the different valvar morphological variants was similar in the outbred and inbred colonies, except for the bifoliate pulmonary valves, which were significantly more frequent in the hamsters from one of the two inbred families. Results of crosses between genetically alike hamsters revealed no significant association between the pulmonary valvar phenotypes as seen in the parents and their offspring. The incidence of bifoliate pulmonary valves, nonetheless, was higher than statistically expected in the offspring of crosses where at least one of the parents possessed a pulmonary valve with two leaflets. Our observations are consistent with the notion that the basic design of the pulmonary valve, in terms of whether it possesses three or two leaflets, relies on genotypic determinants. They also denote that the bifoliate condition of the valve is the consequence of complex inheritance, with reduced penetrance and variable expressivity. Moreover, in showing that the incidence of the bifoliate pulmonary valve significantly differs in two different isogenetic backgrounds, our data suggest that genetic modifiers might be implicated in directing the manifestation of such specific pulmonary valvar malformations. Finally, our findings indicate that factors other than the genotype, operating during embryonic life and creating developmental noise, or random variation, play a crucial role in the overall phenotypic variation involving the pulmonary valve.     

Associated malformations and chromosomal anomalies in 42 cases of prenatally diagnosed diaphragmatic hernia

We present a retrospective study of the frequency and type of associated malformations and chromosomal anomalies in 42 consecutive cases of congenital diaphragmatic hernia (CDH) diagnosed in utero during the period from 1985 to 1999. In 26% (11/42) of the cases, associated malformations were detected. Chromosomal anomalies were present in 9.5% (4/42). In this group of 15 cases (15/42 = 36%) with associated malformations or chromosomal anomalies, all cases, except one, had prenatal sonographic evidence of additional problems. The survival rate of fetuses with CDH and associated malformations or chromosomal anomalies was poor (1/15). Therefore, the overall survival rate of in utero‐diagnosed CDH was only 31% (13/42), while isolated left CDH had a survival rate of 52% (12/23). The in utero diagnosis of CDH implies a detailed echographic examination to exclude additional anomalies. The risk for a syndromal or chromosomal malformation becomes small when no additional anomalies are seen on ultrasound.     

Expanding the spectrum of ADNP-related disorder-Antenatally diagnosed congenital diaphragmatic hernia and a novel de novo mutation in ADNP gene

De novo heterozygous ADNP variants have been associated with a complex neurological phenotype characterized primarily by neurodevelopmental delay. Cardiac and renal anomalies have additionally been observed in a few patients. All reported cases to date have been ascertained postnatally. Congenital diaphragmatic hernia (CDH) has been previously observed in one child diagnosed with a de novo ADNP-related neurodevelopmental disorder. We report a fetus who presented with syndromic CDH associated with a de novo heterozygous ADNP variant.     

The expanding clinical phenotype of germline ABL1‐associated congenital heart defects and skeletal malformations syndrome

Congenital heart defects and skeletal malformations syndrome (CHDSKM) is a rare autosomal dominant disorder characterized by congenital heart disease, skeletal abnormalities, and failure to thrive. CHDSKM is caused by germline mutations in ABL1. To date, three variants have been in association with CHDSKM. In this study, we describe three de novo missense variants, c.407C>T (p.Thr136Met), c.746C>T (p.Pro249Leu), and c.1573G>A (p.Val525Met), and one recurrent variant, c.1066G>A (p.Ala356Thr), in six patients, thereby expanding the phenotypic spectrum of CHDSKM to include hearing impairment, lipodystrophy‐like features, renal hypoplasia, and distinct ocular abnormalities. Functional investigation of the three novel variants showed an increased ABL1 kinase activity. The cardiac findings in additional patients with p.Ala356Thr contribute to the accumulating evidence that patients carrying either one of the recurrent variants, p.Tyr245Cys and p.Ala356Thr, have a high incidence of cardiac abnormalities. The phenotypic expansion has implications for the clinical diagnosis of CHDSKM in patients with germline ABL1 variants.     

Siblings with profound connective tissue disease: First report of biallelic TGFBR1-related Loeys-Dietz syndrome

Heterozygous missense variants in TGFBR1, encoding one subunit of the transforming growth factor-beta receptor, are a well-established cause of Loeys-Dietz syndrome (LDS)—an autosomal dominant disorder with variable phenotypic expression. Patients with LDS have compromised connective tissues that can result in life-threatening arterial aneurysms, craniosynostosis, characteristic craniofacial and skeletal anomalies, skin translucency, and abnormal wound healing. We report a full sibship with a biallelic type of TGFBR1-related disease. Each born at 38 weeks had aortic root dilation, congenital diaphragmatic hernia (CDH), skin translucency, and profound joint laxity at birth. Both had progressive dilation of the aorta and recurrence of a diaphragmatic defect after plication early in infancy. Patient 1 died at 66 days of age and Patient 2 is alive at 4 years and 4 months of age with multiple morbidities including cystic lung disease complicated by recurrent pneumothoraces and ventilator dependence, craniosynostosis, cervical spine instability, progressive dilation of the aorta, worsening pectus excavatum, large lateral abdominal wall hernia, and diffuse aortic ectasia. Fibroblasts cultured from Patient 2 showed decreased TGF-β responsiveness when compared to control fibroblasts, consistent with previous observations in cells from individuals with autosomal dominant LDS. Whole genome copy number evaluation and sequencing for both patients including their parents as reference revealed compound heterozygous variants of uncertain clinical significance in exon 2 of TGFBR1 (c.239G>A; p.Arg80Gln paternal and c.313C>G; p.His105Asp maternal) in both siblings in trans. Each parent with their respective variant has no apparent medical issues and specifically no LDS characteristics. Neither of these variants have been previously reported. Thousands of patients have been diagnosed with LDS—an established autosomal dominant disease. These siblings represent the first reports of biallelic TGFBR1-related LDS and expand the differential diagnosis of CDH.     

Visceral anomalies in the Apert syndrome

We report on visceral anomalies found in 136 patients with Apert syndrome. Autopsies were only performed on 12 of these cases. Thus, the percentage of anomalies found in our patients should be considered a minimum estimate because of the possibility of clinically silent visceral anomalies, minor internal anomalies, and anatomic variations. Cardiovascular and genitourinary anomalies were found most commonly, occurring in 10% and 9.6%, respectively. As expected, complex and multiple cardiac anomalies were frequently associated with early death. Among genitourinary anomalies, hydronephrosis (3%) and cryptorchidism (4.5%, n =; 66 males) occurred most commonly. In contrast, anomalies of the respiratory system (1.5%) and gastrointestinal anomalies (1.5%) occurred with lower frequency. The finding of a solid cartilaginous trachea is particularly important because no case was diagnosed during life but rather, only at autopsy. Because cardiovascular and genitourinary anomalies occur with significant frequency, they should be considered in the workup of all Apert newborn infants. We also recommend MRI study of the trachea in any infant with signs and symptoms of lower respiratory compromise. © 1993 Wiley-Liss, Inc.     

Impaired structural remodelling of pulmonary arteries in newborns with congenital diaphragmatic hernia: a histological study of 29 cases

Congenital diaphragmatic hernia (CDH) is associated in many cases with lung hypoplasia and pulmonary hypertension (PH). The pathogenetic mechanisms underlying the pulmonary hypertension in CDH are not completely understood. In order to alleviate the pulmonary hypertension, new therapeutic modalities have been introduced including extracorporeal membrane oxygenation (ECMO). This paper reports a study of the histology of the lungs of 29 CDH autopsy cases, with special attention to the pulmonary arteries, and relating the findings to gestational age and ECMO treatment. Formalin-fixed and paraffin-embedded specimens were stained with haematoxylin and eosin (H&E) and elastic van Gieson (EvG) stains, followed by morphometric measurements of the arterial media and adventitia. As expected, there was a significant decrease in adventitial percentage and total wall thicknesses of small pulmonary arteries with an external diameter less than or equal to 150 µm in term control newborns compared with pre-term controls ( p=0·0004 and 0·05). In CDH newborns, all the measured values of the arterial wall remained significantly higher. The increase of adventitial thickness also affected the supernumerary arteries in CDH neonates. CDH newborns subjected to ECMO treatment showed a significantly thinner arterial adventitia than CDH cases who did not receive ECMO ( p=0·0001), the former approaching normal values. These results indicate that in CDH, there is failure of the normal arterial remodelling processes occurring in the perinatal period. The adventitial thickening, which has been reported previously in term CDH patients only, was related in the present study to differences in gestational ages. This appears to be partially reversed by ECMO treatment, thus constituting one of the mechanisms by which ECMO treatment aids in alleviating the associated PH in CDH newborns. Copyright © 1999 John Wiley & Sons, Ltd.     

Congenital defects of lower limbs and associated malformations: A population based study

As part of a detailed study of limb defects and associated patterns of congenital malformations, cases with lower limb deficiencies were analysed separately. We identified a total of 130 cases with deficiencies of the lower limbs without defects of the upper limbs. This gives an incidence of 1.07/10,000 livebirths, or 1/9,337 for this group of limb defects. Most common were femur deficiencies and deficiencies of the foot. A preponderance of males was found in the group of transverse defects of the leg (fibula/tibia deficiencies) and central axis deficiencies, while females had significantly more often longitudinal tibia defects and preaxial ray defects. © 1993 Wiley-Liss, Inc.     

Frequency of associated anomalies in congenital hypoplasia of depressor anguli oris muscle: A study of 50 patients

Aside from congenital heart disease, anomalies associated with unilateral hypoplasia of the depressor anguli oris muscle have not been well-documented in large series. We evaluated the associated anomalies in 50 infants or children with this disorder (male:female = 2:1) and found accompanying anomalies in 35 (70%) of 50 cases. They included anomalies of the head and neck (48%), heart (44%), skeleton (22%), genitourinary tract (24%), central nervous system (10%), gastrointestinal tract (6%), and miscellaneous minor anomalies (8%). Nearly half of our cases (22/50) had at least 2 associated systemic anomalies. Failure to thrive and psychomotor retardation were found in 5 (10%) and 3 (6%) patients, respectively, on follow-up. Three infants died neonatally of severe heart disorders, and the other one died of central nervous system anomalies. The above findings indicate that a thorough search for associated anomalies, particularly in the cardiovascular system, should be performed in all newborns with asymmetric crying face. Am. J. Med. Genet. 71:215–218, 1997. © 1997 Wiley-Liss, Inc.     

Maternal age and prevalence of isolated congenital heart defects in an urban area of the United States

Although maternal age has been associated with a number of birth defects in several reports, the literature on the association of maternal age with isolated congenital heart defect (CHD) phenotypes has been limited. We evaluated CHD prevalence based on a cohort of 5,289 infants and fetuses with isolated CHDs born during the period 1968–2005 and ascertained by the Metropolitan Atlanta Congenital Defects Program (MACDP) among residents of five central counties in Atlanta. For our denominator, we obtained information on births to residents of the same counties from vital records (n = 1,301,143). We calculated prevalence ratios for 23 CHD phenotypes by several maternal age categories, using the group 25–29 years of age as a reference group. We used Poisson regression models to estimate adjusted prevalence ratios (aPRs) and 95% confidence intervals (CIs), controlling for maternal race, infant sex, and birth cohort. A maternal age of 35 years or older was associated with an increased prevalence for several CHD phenotypes: laterality defects (aPR = 2.06; CI 1.22–3.48), all conotruncal defects (aPR = 1.30; CI 1.03–1.65), and specifically for dextro‐transposition of the great arteries (aPR = 1.65; CI 1.10–2.48), coarctation of the aorta (aPR = 1.54; CI 1.10–2.16), ventricular septal defects (aPR = 1.20; CI 1.06–1.36), and atrial septal defects (aPR = 1.36; CI 1.05–1.77). Our findings suggest that the birth prevalence of specific isolated CHDs varies with maternal age. Further studies are warranted to corroborate these observations, taking into account potential confounding by known modifiable risk factors. Published 2011 Wiley‐Liss, Inc.