Cystic hygroma and congenital diaphragmatic hernia: early prenatal sonographic evaluation of Fryns' syndrome

Fryns Syndrome Associated with Recessive Mutations in PIGN in two Separate Families

Fryns syndrome is an autosomal recessive condition characterized by congenital diaphragmatic hernia (CDH), dysmorphic facial features, distal digital hypoplasia, and other associated malformations, and is the most common syndromic form of CDH. No gene has been associated with this condition. Whole-exome sequence data from two siblings and three unrelated individuals with Fryns syndrome were filtered for rare, good quality, coding mutations fitting a recessive inheritance model. Compound heterozygous mutations in PIGN were identified in the siblings, with appropriate parental segregation: a novel STOP mutation (c.1966C>T: p.Glu656X) and a rare (minor allele frequency <0.001) donor splice site mutation (c.1674+1G>C) causing skipping of exon 18 and utilization of a cryptic acceptor site in exon 19. A further novel homozygous STOP mutation in PIGN (c.694A>T: p.Lys232X) was detected in one unrelated case. All three variants affected highly conserved bases. The two remaining cases were negative for PIGN mutations. Mutations in PIGN have been reported in cases with multiple congenital anomalies, including one case with syndromic CDH. Fryns syndrome can be caused by recessive mutations in PIGN. Whether PIGN affects other syndromic and non-syndromic forms of CDH warrants investigation.

Genetic syndromes and prenatally detected renal anomalies

Renal anomalies are frequently detected on the routine second trimester scan offered to all pregnant women in the UK. These anomalies may be isolated but can also be associated with other congenital anomalies. Many combinations of ultrasound scan findings constitute recognised genetic entities. Knowledge of these conditions is essential for adequate management of the pregnancy and subsequent balanced parental counselling. This short review discusses the common genetic syndromes associated with the renal abnormalities identified on the antenatal ultrasound scan, and also provides an overview of renal symptoms in chromosome imbalances and after teratogenic influences.

First trimester ultrasonography in screening and detection of fetal anomalies

An obstetrical ultrasound examination provides invaluable information regarding the fetus. Until the mid-1980s, ultrasound in the first trimester was limited to localization of the pregnancy, establishing viability, and accurate dating. With the advent of high-resolution ultrasound and transvaginal scanning, a significant amount of information about the fetus can be gained and provided to the patient at a very early stage in gestation. This article provides an overview of the role of first trimester (11-13 + 6 weeks' gestation) ultrasound in screening and diagnosis of fetal anomalies. The first trimester is an ideal time for screening for aneuploidy, primarily due to the advantages that nuchal translucency (NT) measurement provides. NT measurement is also useful in establishing the risk of congenital cardiac disorders and a number of genetic and non-genetic syndromes. Significant NT thickening is associated with an increase in perinatal morbidity and mortality. Potential mechanisms resulting in increased NT are discussed. A number of new ultrasound markers for fetal aneuploidy have been investigated over the past several years, some of which appear to improve the screening efficacy of early ultrasonography. The role of these is reviewed. A number of fetal anomalies can now be consistently diagnosed in the first trimester. Their appearance at this early gestational age is discussed as well. It is clear that, data obtained by first trimester ultrasound are useful in counseling expectant parents and in planning the appropriate follow-up.

Cardiovascular malformations in Fryns syndrome: is there a pathogenic role for neural crest cells?

We performed a comprehensive literature and case report review to characterize the cardiovascular malformations (CVMs) associated with Fryns syndrome (OMIM #229850), a multiple congenital anomaly/mental retardation syndrome consisting of diaphragmatic defects, significant pulmonary hypoplasia, distinctive facial appearance, distal digital hypoplasia, and numerous other external and internal anomalies. A total of 112 patients meeting diagnostic guidelines for Fryns syndrome were identified, of whom 82 met narrowly defined criteria (Group I) and 30 met broader diagnostic criteria (Group II). Twelve patients reported as having Fryns syndrome with atypical features (Group III) were also analyzed. A CVM was reported in 51% (42 of 82) of Group I patients, most commonly an atrial or ventricular septal defect (VSD) (23 of 42, 55%). Conotruncal and aortic arch CVMs were common (11 of 42, 26%), but not significantly so compared to the general population of infants to age 1 year [Ferencz et al., 1997]. Recognizing that minor septal defects associated with congenital diaphragmatic hernia (CDH) may occur in response to altered hemodynamics (instead of being a bonafide CVM), we excluded four patients reported as having hemodynamically insignificant VSDs. Following these exclusions, conotruncal CVMs were found more commonly than in the general population (11 of 38, 29%, P < or = 0.025). In Group II, 9 of 30 (30%) had a CVM with no predominant type among the small number of cases reviewed. Among the atypical Fryns syndrome patients in Group III, half (6 of 12, 50%) had a CVM; most (4 of 6, 67%) were conotruncal, in particular, type B interrupted aortic arch (3 of 4). Patients with Fryns syndrome have a high rate of CVMs, warranting thorough cardiac evaluation including echocardiogram (fetal and/or postnatal) in all patients, similar to the evaluation for other patients with diaphragmatic hernia. The possible association between conotruncal CVMs and Fryns syndrome may provide additional support for an etiologic role of genes related to neural crest cell development in the pathogenesis of Fryns syndrome and hence, congenital diaphragmatic hernia.

Cleft of the secondary palate without cleft lip diagnosed with three-dimensional ultrasound and magnetic resonance imaging in a fetus with Fryns' syndrome

We present a case of Fryns' syndrome diagnosed prenatally using three-dimensional (3D) ultrasonography and magnetic resonance imaging (MRI). A cleft of the soft palate was diagnosed using 3D thick-slice ultrasonography. Other sonographic findings included a right diaphragmatic hernia, enlarged echogenic kidneys and severe polyhydramnios. The detection of the cleft palate was instrumental in suggesting the diagnosis of Fryns' syndrome in a fetus which also had a diaphragmatic hernia. These findings were also demonstrated with prenatal MRI. The technique of imaging the soft palate en face using a thick-slice technique is presented.

Increased nuchal translucency with normal karyotype

Increased fetal nuchal translucency (NT) thickness between 11 and 14 weeks' gestation is a common phenotypic expression of chromosomal abnormalities, including trisomy 21. However, even in the absence of aneuploidy, nuchal thickening is clinically relevant because it is associated with an increase in adverse perinatal outcome caused by a variety of fetal malformations, dysplasias, deformations, dysruptions, and genetic syndromes. Once the presence of aneuploidy is ruled out, the risk of perinatal outcome dose not statistically increase until the nuchal translucency measurement reaches 3.5 mm or more (>99th percentile). This increase in risk occurs in an exponential fashion as the NT measurement increases. However, if the fetus survives until midgestation, and if a targeted ultrasound at 20 to 22 weeks fails to reveal any abnormalities, the risk of an adverse perinatal outcome and postnatal developmental delay is not statistically increased.

Population-based study of the outcome following the prenatal diagnosis of cystic hygroma

OBJECTIVE

To identify the population prevalence, pregnancy outcome, and the pattern of associated anomalies with a prenatal diagnosis of cystic hygroma.

DESIGN

We analysed the pregnancy outcomes from 99 cases of prenatally diagnosed cystic hygroma reported to the Trent Congenital Anomalies Register from 1 January 1997 to 31 December 1999, by means of an outcome reporting form completed by the notifying centre.

RESULTS

We identified a population prevalence of 1 in 1775 livebirths for prenatally diagnosed cystic hygroma. There were 64 terminations of pregnancy, 19 spontaneous pregnancy failures, and 16 livebirths. Of the 87 pregnancies karyotyped, 53 (61%) demonstrated aneuploidy with Turner syndrome being the most common, 29 (33%). There were a large variety of structural malformations identified, however, only 14 out of 83 terminations of pregnancy and spontaneous pregnancy failures had post-mortem examinations. Termination of pregnancy for Turner syndrome not complicated by identified structural malformations was the norm. Of the 16 livebirths, only 6 were normal at birth, 1 other has had successful hygroma surgery. Four of the liveborn infants have since died.

CONCLUSIONS

The 'normal outcome' rate from pregnancies complicated by prenatally diagnosed cystic hygroma is less than 10% in this study (6/99). Prenatal diagnosis of cystic hygroma requires careful assessment of the fetus, with regard to both karyotyping and ultrasound. Post-mortem examination should be encouraged after termination of pregnancy, or spontaneous pregnancy loss. This is important not just to the current pregnancy but also for future pregnancies.

Fryns syndrome: A review of the phenotype and diagnostic guidelines

Fryns syndrome (FS) is the commonest autosomal recessive syndrome associated with congenital diaphragmatic hernia (CDH) and comprises CDH, pulmonary hypoplasia, craniofacial anomalies, distal limb hypoplasia, and internal malformations. Although there have been more than 50 case reports on probands with FS, the diagnostic guidelines were formulated from a review of eight patients and modifications to the guidelines have only once been suggested. Recently, several case reports have described new anomalies in FS and other papers have highlighted the variation in expressivity found in FS. This paper examines the medical literature on FS to define the phenotype and to review the diagnostic guidelines. We conclude that CDH with brachytelephalangy and/or nail hypoplasia is strongly suggestive of the diagnosis and that pulmonary hypoplasia, craniofacial dysmorphism, orofacial clefting, and polyhydramnios are sufficiently frequent to be diagnostically useful. Other distinctive malformations that are consistent with FS include ventricular dilatation or hydrocephalus, agenesis of the corpus callosum, neuronal or cerebellar heterotopias, abnormalities of the aorta, renal cysts, dilatation of the ureters, bicornuate uterus, renal dysplasia, proximal thumbs, and broad clavicles.

Cleft-palate lateral synechia syndrome: insight into the phenotypic spectrum of Fryns syndrome?

BACKGROUND

In 1972, Fuhrmann et al. (Humangenetik 1972;14:196-203) described a novel syndrome consisting of cleft palate (CP) and lateral synechiae (LS) between the palate and the floor of the mouth. This constellation of malformations, since denoted as cleft-palate lateral synechiae syndrome (CPLS), is a rare syndrome; only five cases have been reported since the original description. Because of the paucity of recognized cases, little is known regarding the phenotypic spectrum of this presumably autosomal dominant condition.

CASES

We report two unrelated patients who presented with remarkably similar phenotypic features, including multiple intraoral synechiae (filiforme intraalveolar bands), cleft palate, micrognathia, and redundant lower lip tissue. Their phenotypic findings indicate a diagnosis of CPLS; however, case 3 (the monozygotic twin of case 2) had classic phenotypic features of Fryns syndrome.

CONCLUSIONS

This report presents two new cases of CPLS, and suggests that the CPLS phenotype may represent the mild end of the Fryns syndrome phenotypic spectrum. Supplementary material for this article can be found on the Birth Defects Research (Part A) website (http://www.interscience.wiley.com/ jpages/1542-0752/suppmat/67/fig5.xls).

Outcome of pregnancy in chromosomally normal fetuses with increased nuchal translucency in the first trimester

OBJECTIVES

To study the outcome of chromosomally normal pregnancies with increased nuchal translucency at the 10-14-week scan.

DESIGN

Retrospective study of 1320 chromosomally normal singleton pregnancies with nuchal translucency of > or = 3.5 mm. In addition to fetal karyotyping these patients were managed with follow-up scans at 14-16 and 20-22 weeks, specialist fetal echocardiography and in selected cases by infection screening and further genetic testing.

RESULTS

In the 1320 pregnancies there were 68 (5.15%) spontaneous abortions or intrauterine deaths, 18 (1.36%) neonatal and infant deaths and 154 (11.67%) terminations of pregnancy. In the 1080 (81.82%) survivors, 60 (5.56%) had abnormalities requiring medical or surgical treatment or leading to mental handicap. The chance of a livebirth with no defects in the group with nuchal translucency of 3.5-4.4 mm was 86%, for those with translucency of 4.5-5.4 mm it was 77%, for those with translucency of 5.5-6.4 mm it was 67%, and for those with translucency of > or = 6.5 mm it was 31%.

CONCLUSIONS

Increased fetal nuchal translucency is associated with chromosomal abnormalities, many fetal defects and genetic syndromes. In the majority of cases a series of antenatal investigations, including fetal karyotyping, detailed scans, fetal echocardiography, as well as genetic testing and infection screening, that can be completed by 20 weeks of gestation would distinguish between the pregnancies destined to result in adverse outcome and those leading to the delivery of infants without major defects.

First-trimester ultrasound

There has been an increase in the use of fetal ultrasound in the first trimester. This article reviews the published literature with emphasis on fetal nuchal translucency (NT). When measured according to well-defined guidelines, increased NT identifies about 80% of chromosomal anomalies for a false-positive rate of about 5%. Increased NT may indicate the presence of structural defects or genetic disorders, and it is relatively frequently seen in monochorionic pregnancies prone to develop twin-twin transfusion syndrome.

Variability in the phenotypic expression of fryns syndrome: A report of two sibships

We report on two sibships with four fetuses of 12, 15, 17, and 20 weeks of gestation, respectively, and 1 preterm baby of 31 weeks of gestation affected by a multiple congenital disorder with manifestation suggestive of Fryns syndrome. In addition to the characteristic malformation pattern in Fryns syndrome, they presented with fetal hydrops, cystic hygroma, and multiple pterygias, allowing prenatal ultrasound diagnosis as early as in the 11th week of gestation. The two affected fetuses of family 1 showed severe craniofacial anomalies with bilateral cleft lip and palate, acral hypoplasia, postaxial oligodactyly, persistent truncus arteriosus, and interrupted aortic arch, asplenia sequence, and complex central nervous system midline malformations. In family 2 with three affected sibs, ear anomalies with atresia of the auditory canals, postaxial hexadactyly, intestinal atresias, callosal defects, and eye colobomas were the most outstanding features. On the basis of the present findings and former reports, the inter- and intrafamiliar phenotypic variability in Fryns syndrome, possible pathogenetic mechanisms, and the value of prenatal diagnosis are discussed. In the pathogenetic discussion, a special emphasis is put on the neural crest cell developmental field.

First trimester screening for structural fetal abnormalities: nuchal translucency sonography

Nuchal translucency refers to the normal subcutaneous space, observed on first trimester ultrasound examination, between the skin and the cervical spine in the fetus. Increased nuchal translucency is known to be associated with an increased risk of aneuploidy, particularly Down syndrome. In addition to this association with aneuploidy, multiple studies have now identified increased nuchal translucency as a nonspecific marker of a wide range of fetal structural abnormalities, to include congenital diaphragmatic hernia, cardiac defects, and various genetic syndromes. The degree of nuchal translucency is directly related to the prevalence of fetal anomalies and may have prognostic significance, especially when found in association with other anomalies. The pathophysiology of increased nuchal translucency is uncertain but may be the result of cardiac failure or alterations in lymphatic drainage. Increased nuchal translucency may identify pregnancies that require further assessment, to include additional sonographic evaluation and possible fetal echocardiography. Further evaluation is required to assess the role of nuchal translucency screening in the general population.

Cystic hygroma in the fetus and newborn

Cystic hygromas are developmental abnormalities of the lymphoid system that occur at sites of lymphatic-venous connection, most commonly in the posterior neck. They are frequently associated with karyotypic abnormalities, various malformation syndromes, and several teratogenic agents. The disease course of an infant with cystic hygroma is unpredictable. When diagnosed prenatally, the overall prognosis is poor. Cystic hygroma diagnosed after birth is usually associated with a good prognosis. This article reviews the embryologic, genetic, and pathologic correlates of these lymphatic system abnormalities, as well as the clinical course and outcome of the fetus and newborn with a cystic hygroma. Management strategies are reviewed, including newer nonsurgical therapies for the neonate with a cystic hygroma.

Prenatal evaluation of fetal anomalies

Advances in sonographic imaging have allowed for detailed examination of the fetus. A wide range of abnormalities of the fetal central nervous system, chest, gastrointestinal tract, genitourinary system, and skeleton are detectable by prenatal sonography. This article reviews the sonographic findings and prognostic implications of these abnormalities.

Congenital pulmonary lymphangiectasia and other anomalies in a child: provisionally unique syndrome?

Congenital pulmonary lymphangiectasis is a rare anomaly that is causally heterogeneous. It can occur as either an isolated finding or one manifestation of several multiple congenital anomaly syndromes. We describe a child with congenital pulmonary lymphangiectasis and the anomalies who likely has a provisionally unique condition.

Correlation between nuchal thickness and abnormal karyotype in first trimester fetuses

OBJECTIVE

To evaluate the accuracy of ultrasound measurement of nuchal thickness in first trimester fetuses for predicting fetal karyotype.

DESIGN

A prospective study of the nuchal thickness of fetuses measured during an ultrasound examination in all women undergoing first trimester chorionic villus sampling (CVS).

SETTING

Two major public hospitals and two associated private practices between 7 September 1993 and 6 September 1994.

PARTICIPANTS

Pregnant women with various indications for CVS (in 82% because of maternal age).

RESULTS

1306 women underwent CVS, including 11 with twin pregnancies: 1317 fetuses were tested. Karyotype results were obtained for 1312 fetuses: 41 (3.1%) had an abnormal karyotype, and 20 of these (49%) had a nuchal thickness measurement of 3 mm or more, compared with 44 (3.5%) of the 1271 fetuses with a normal karyotype. Of the 21 fetuses shown to have trisomy 21, 12 would have been detected if a nuchal thickness of 3 mm or more had been used as an indicator, giving a sensitivity of 57%. Nuchal thickness measurements of 1 or 2 mm excluded trisomy 21 with a negative predictive value of 99.3%. Fetuses with moderate nuchal thickening, normal karyotype and no other problems noted on the initial ultrasound scan had neonatal outcomes similar to those in the general obstetric population.

CONCLUSION

Nuchal thickening in the first trimester (10 weeks on) of pregnancy in a high risk population is a powerful indicator of increased risk of aneuploidy.

Fryns syndrome phenotype and trisomy 22

Trisomy 22 was detected in a 32-week-old fetus born to an overweight mother with hypertension. Severe intrauterine growth retardation was associated with phenotypic manifestations of Fryns syndrome: diaphragmatic hernia, facial defects, and nail hypoplasia with short distal fifth phalanges. This is the second report of congenital diaphragmatic hernia in trisomy 22. This case demonstrates the importance of karyotyping malformed fetuses or newborns, even if a nonchromosome syndrome seems identifiable on clinical grounds. To date, at least 10 cases of Fryns syndrome have been reported without chromosome analysis.

Antenatal diagnosis of cystic hygroma or nuchal pad--report of 92 cases with follow up of survivors

Information on the outcome of pregnancy was collected on 92 fetuses with cystic hygroma or nuchal pad, identified prenatally. Forty three (47% of the total) were associated with abnormal karyotype. Twenty five (27%) had normal karyotype but an additional abnormality was identified on ultrasound scan. There were 10 liveborn babies in this group of whom seven had significant problems postnatally. In twenty four (26%) cases the cystic hygroma or nuchal pad was an isolated finding. Seventeen (89% of those in which the pregnancy was electively continued) were liveborn and reported to be normal. Those with a normal karyotype, no other anomaly identified on antenatal scan, and smaller non-septate lesions have a good prognosis.

Fryns syndrome survivors and neurologic outcome

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, including imaging for structural brain malformation, is strongly advised.

Fryns syndrome: two further cases without lateral diaphragmatic defects

We report on two unrelated infants with Fryns syndrome but without lateral diaphragmatic defects. In case 1, a female stillborn, pertinent findings included a coarse facies, cleft palate, short neck with a broad pterygium, heart defect, lung hypoplasia, omphalocele, urogenital malformations, anal atresia, and distal digital hypoplasia. Case 2 showed a coarse facies with cleft lip and palate, para-oesophageal hernia with herniation of the stomach into the thoracic cavity, malrotation of the intestine, hydronephrosis, and anal atresia. At age 14 months she was developmentally severely retarded. These observations represent the 11th and 12th reports of probable Fryns syndrome without lateral diaphragmatic defect.

Skeletal manifestations in Fryns syndrome

We report on a female baby with Fryns syndrome who died soon after birth. The patient had short limbs, coarse face, hypoplastic lungs, diaphragmatic hernia, and acral hypoplasia. Literature review disclosed varying degrees of skeletal manifestations in Fryns syndrome; short limbs may be a component of Fryns syndrome.

Fryns syndrome: a rare familial cause of congenital diaphragmatic hernia

Fryns syndrome is a rare autosomal recessive disorder characterized by diaphragmatic hernia and multiple anomalies. Almost all infants have died at birth, and survivors have had severe mental retardation. The authors report on a family in which three children had diaphragmatic hernia diagnosed prenatally. The first child died of severe pulmonary hypoplasia in the neonatal period. The second survived after diaphragmatic hernia repair, and was found to have Fryns syndrome based on the spectrum of associated anomalies and the family history. He has done well except for significant gastroesophageal reflux, mild developmental delay, and mild hypotonia. The third child's diaphragmatic hernia was diagnosed early during fetal life, and the parents chose to terminate the pregnancy. These cases illustrate the spectrum of Fryns syndrome and the importance of a family history in patients with congenital diaphragmatic hernia. This is the first report of survival of a patient with Fryns syndrome without severe mental retardation.

Transvaginal ultrasonography and transabdominal embryoscopy in the first-trimester diagnosis of Smith-Lemli-Opitz syndrome, type II

OBJECTIVE

Our goal was to demonstrate the efficacy of transabdominal embryoscopy in the first trimester of pregnancy.

STUDY DESIGN

A patient at risk for Smith-Lemli-Opitz syndrome, type II, was referred for prenatal diagnosis at 11 weeks 5 days of gestation.

RESULTS

A transvaginal ultrasonographic examination revealed the presence of a nuchal membrane and bilateral polydactyly. A transabdominal embryoscopy confirmed the diagnosis of polydactyly. The patient had an unremarkable postprocedure course before termination of pregnancy 5 days later. In a second pregnancy embryoscopy revealed a normal fetal hand despite a suggestion on transvaginal ultrasonography that there was polydactyly. On the basis of this information the patient elected to continue the pregnancy, and a normal baby was delivered at 35 weeks.

CONCLUSION

This case validates the efficacy of noninvasive and invasive techniques, used adjunctively, in the first-trimester diagnosis of a lethal fetal condition composed of subtle phenotypic manifestations.

Fryns syndrome: a new definition

Fryns syndrome is a lethal, autosomal recessive syndrome of multiple congenital anomalies described by Fitch et al. in 1978 and Fryns et al. in 1979. As originally described, the major diagnostic criteria included abnormal facies; small thorax with widely spaced, hypoplastic nipples; distal limb and nail hypoplasia; and diaphragmatic hernia with pulmonary hypoplasia. Malformations involving other systems occurred irregularly in published reports. We reviewed 41 published cases of Fryns syndrome and added 4 cases of our own. The major diagnostic criteria described by Fryns were consistent in all cases with the exception of two criteria. Narrow thorax with hypoplastic nipples and gastrointestinal anomalies were present in less than 50% of the cases. Although for 16 of the 41 published cases there was no information on central nervous system findings, 21 of the 29 remaining cases (72%) had CNS malformations. These lesions were absence of corpus callosum, arhinencephaly, and heterotopia of cerebral and cerebellar tissue. Similarly, for 12 of the 41 published cases there was no information on cardiovascular findings but 29 of the 33 remaining cases (88%) had congenital heart disease. These lesions were ventricular septal defects, arterial septal defects, and persistent left superior vena cava. We conclude that central nervous system anomalies and congenital heart disease should be added to the major diagnostic criteria of Fryns syndrome.