Diagnostic dilemmas in the short rib-polydactyly syndrome group

Primary cilia in hard tissue development and diseases

Bone and teeth are hard tissues. Hard tissue diseases have a serious effect on human survival and quality of life. Primary cilia are protrusions on the surfaces of cells. As antennas, they are distributed on the membrane surfaces of almost all mammalian cell types and participate in the development of organs and the maintenance of homeostasis. Mutations in cilium-related genes result in a variety of developmental and even lethal diseases. Patients with multiple ciliary gene mutations present overt changes in the skeletal system, suggesting that primary cilia are involved in hard tissue development and reconstruction. Furthermore, primary cilia act as sensors of external stimuli and regulate bone homeostasis. Specifically, substances are trafficked through primary cilia by intraflagellar transport, which affects key signaling pathways during hard tissue development. In this review, we summarize the roles of primary cilia in long bone development and remodeling from two perspectives: primary cilia signaling and sensory mechanisms. In addition, the cilium-related diseases of hard tissue and the manifestations of mutant cilia in the skeleton and teeth are described. We believe that all the findings will help with the intervention and treatment of related hard tissue genetic diseases.

Whole-exome sequencing identified two novel mutations of DYNC2LI1 in fetal skeletal ciliopathy

Background

Skeletal ciliopathies are a group of clinically and genetically heterogeneous disorders with the spectrum of severity spanning from relatively mild to prenatally lethal. The aim of our study was to identify pathogenic mutations in a Chinese family with two siblings presenting a Short‐rib polydactyly syndrome (SRPS)‐like phenotype.

Method

Karyotyping and NGS‐based CNVseq were performed. Obtaining the negative results in karyotyping and CNVseq, whole‐exome sequencing (WES) using genomic DNA (gDNA) extracted from the umbilical cord blood of the first fetus was carried out, followed by bioinformation analysis. The candidate pathogenic variants were confirmed by Sanger sequencing in the family.

Results

No chromosomal abnormalities and pathogenic copy number variations (CNVs) were detected in the affected fetus with SRPS‐like phenotype. WES analysis identified two novel compound heterozygous variants in DYNC2LI1, c.358G>T (p.Pro120Ser; NM_001193464), and c.928A>T (p.Lys310Ter; NM_ 001193464). Bioinformatics analysis suggested that c.358G>T (p.Pro120Ser) was likely pathogenic and c.928A>T (p.Lys310Ter) was pathogenic. Sanger sequencing of the two variants in family reveal that c.358G>T was from paternal origin and c.928A>T was from maternal origin, and the second affected fetus had the same compound heterozygous variants in DYNC2LI1. Definitive diagnosis of short‐rib thoracic dysplasia 15 with polydactyly (SRTD15) was made in the family.

Conclusion

Our results expand the mutational spectrum of DYNC2LI1 in severe skeletal ciliopathies. WES facilitates the accurate prenatal diagnosis of fetal skeletal ciliopathy, and provides helpful information for genetic counseling.

Ellis-van Creveld syndrome: Report of a case and recurrent variant

BACKGROUND

Ellis-van Creveld syndrome (EvCS) is a rare autosomal recessive skeletal dysplasia that is characterized by short stature, short limbs, short ribs, polydactyly and structural heart defect. Despite locus heterogeneity, in the majority of the cases, the disorder segregates with mutations in the EVC and EVC2 genes, notably mutations with truncating protein as a final sequence. In the present study, we report the prenatal findings and genetic analysis of a terminated pregnancy affected by severe thoracic and skeletal dysplasia.

METHODS

After detailed physical and clinical examination, whole exome sequencing (WES) was performed and the variant was confirmed by Sanger sequencing.

RESULTS

One homozygote variant in EVC2 gene was identified in the fetus (NM_147127, c.942G>A, p.W314X). The EVC2 gene is strongly associated with EvCS, which is consistent with the sonographic findings of the fetus.

CONCLUSIONS

The homozygous p.W314X mutation found in this family was recently reported to be segregated in a consanguineous family originating from Pakistan. The occurrence of the p.W314X mutation in two unrelated families (Iranian and Pakistani) may be the result of an old founder effect or arose because of a mutational hotspot and is supporting evidence for the pathogenicity of this variant. Because skeletal dysplasia belongs to a broad spectrum of syndromes and therefore exhibits considerable background locus and allelic heterogeneity, our report highlights the need for appropriate genetic counseling and supports the feasibility of WES to determine an accurate diagnosis, as well as precise recurrence risk prediction.

Mutations in DYNC2H1, the cytoplasmic dynein 2, heavy chain 1 motor protein gene, cause short-rib polydactyly type I, Saldino-Noonan type

The short-rib polydactyly syndromes (SRPS) are autosomal recessively inherited, genetically heterogeneous skeletal ciliopathies. SRPS phenotypes were historically categorized as types I-IV, with type I first delineated by Saldino and Noonan in 1972. Characteristic findings among all forms of SRP include short horizontal ribs, short limbs and polydactyly. The SRP type I phenotype is characterized by a very small thorax, extreme micromelia, very short, poorly mineralized long bones, and multiple organ system anomalies. To date, the molecular basis of this most severe type of SRP, also known as Saldino-Noonan syndrome, has not been determined. We identified three SRP cases that fit the original phenotypic description of SRP type I. In all three cases, exome sequence analysis revealed compound heterozygosity for mutations in DYNC2H1, which encodes the main component of the retrograde IFT A motor, cytoplasmic dynein 2 heavy chain 1. Thus SRP type I, II, III and asphyxiating thoracic dystrophy (ATD), which also result from DYNC2H1 mutations. Herein we describe the phenotypic features, radiographic findings, and molecular basis of SRP type I.

DYNC2LI1 mutations broaden the clinical spectrum of dynein-2 defects

Skeletal ciliopathies are a heterogeneous group of autosomal recessive osteochondrodysplasias caused by defects in formation, maintenance and function of the primary cilium. Mutations in the underlying genes affect the molecular motors, intraflagellar transport complexes (IFT), or the basal body. The more severe phenotypes are caused by defects of genes of the dynein-2 complex, where mutations in DYNC2H1, WDR34 and WDR60 have been identified. In a patient with a Jeune-like phenotype we performed exome sequencing and identified compound heterozygous missense and nonsense mutations in DYNC2LI1 segregating with the phenotype. DYNC2LI1 is ubiquitously expressed and interacts with DYNC2H1 to form the dynein-2 complex important for retrograde IFT. Using DYNC2LI1 siRNA knockdown in fibroblasts we identified a significantly reduced cilia length proposed to affect cilia function. In addition, depletion of DYNC2LI1 induced altered cilia morphology with broadened ciliary tips and accumulation of IFT-B complex proteins in accordance with retrograde IFT defects. Our results expand the clinical spectrum of ciliopathies caused by defects of the dynein-2 complex.

Targeted next-generation sequencing identifies novel compound heterozygous mutations of DYNC2H1 in a fetus with short rib-polydactyly syndrome, type III

A 26-year-old woman with a past history of fetal skeletal dysplasia was referred to our institution at 24weeks of gestation following a routine sonographic diagnosis of short limbs in the fetus. A fetal ultrasound showed short limbs, a narrow thorax, short ribs with marginal spurs, and polydactyly. Conventional cytogenetics analysis of cultured amniocytes demonstrated that the fetal karyotype was normal. Using targeted exome sequencing of 226 known genes implicated in inherited skeletal dysplasia, we identified compound heterozygous mutations in the DYNC2H1 gene in the fetus with short rib-polydactyly syndrome, type III (SRPS III), c.1151 C>T(p.Ala384Val) and c.4351 C>T (p.Gln1451*), which were inherited from paternally and maternally, respectively. These variants were further confirmed using Sanger sequencing and have not been previously reported. To our knowledge, this is the first report of DYNC2H1 mutations causing SRPS III, in the Chinese population. Our findings expand the number of reported cases of this rare disease, and indicate that targeted next-generation sequencing (NGS) is an accurate, rapid, and cost-effective method in the genetic diagnosis of fetal skeletal dysplasia.

Autopsy observations in lethal short-rib polydactyly syndromes

The short rib-polydactyly syndromes are a heterogeneous group of lethal autosomal recessive disorders (SRP I-IV), which result from cellular ciliary dysfunction during embryogenesis. Diagnosis is conventionally based on radiographic imaging. Since 1976, postmortem investigations of 5 affected fetuses or stillbirths have been undertaken and the visceral abnormalities have been documented. These anomalies are discussed in the context of prenatal differential diagnosis and prognostication following imaging in pregnancy and at autopsy following miscarriage or stillbirth.

Temporal lobe dysplasia: a characteristic sonographic finding in thanatophoric dysplasia

OBJECTIVE

To determine the incidence of temporal lobe dysplasia (TLD) detected on prenatal ultrasound in thanatophoric dysplasia (TD) over an 11-year period in a tertiary referral center.

METHODS

An 11-year retrospective review of perinatal autopsies from 2002 to 2013 was performed to identify cases of TD. The ultrasound images and corresponding reports of all TD cases were examined for the presence of TLD. The same set of images subsequently underwent a retrospective review by a perinatal radiologist with knowledge of the features of TLD to determine whether they could be identified.

RESULTS

Thirty-one cases of TD underwent perinatal autopsy, and prenatal ultrasound imaging was available for review in 24 (77%). Mean gestational age at diagnosis of TD was 21.3 (range, 18-36) weeks. TLD was identified and reported in 6/24 (25%) cases; all six cases occurred after 2007. Retrospective interpretation of the ultrasound images identified features of TLD in 10 additional cases. In total, 16/24 (67%) cases displayed sonographic evidence of TLD. Temporal trends showed that TLD features were present in 50% (5/10) of all TD cases between 2002 and 2006 and in 79% (11/14) of those detected between 2007 and 2013.

CONCLUSIONS

At present, the detection rate of TLD by ultrasound is low but may be increased by modified brain images that enhance visualization of the temporal lobes. Prenatal identification of TLD may help in the prenatal diagnosis of TD and thus provide more accurate prenatal counseling and guide molecular investigations to confirm the specific diagnosis of TD.

Prenatal diagnosis and molecular genetic analysis of short rib-polydactyly syndrome type III (Verma-Naumoff) in a second-trimester fetus with a homozygous splice site mutation in intron 4 in the NEK1 gene

OBJECTIVE

To demonstrate perinatal imaging findings and to investigate the mutation in the NEK1 gene in a fetus with type III short rib-polydactyly syndrome (SRPS) (Verma-Naumoff).

CASE REPORT

A 34-year-old woman with no past history of fetal SRPS was referred to the hospital at 21 weeks of gestation because of sonographic diagnosis of short limbs in the fetus. Fetal ultrasound revealed a narrow thorax, short ribs, short limbs with marginal spurs, and postaxial hexadactyly in both the hands and feet. A diagnosis of SRPS III (Verma-Naumoff) was made. Amniocentesis was performed. The karyotype was 46,XY. Molecular genetic analysis of the amniotic fluid cells identified a homozygous splice site mutation in intron 4 (c.331-1 A > G) or IVS4-1 A > G in the NEK1 gene. The parents were heterozygous for the mutation. The pregnancy was subsequently terminated and a malformed fetus was delivered with prominent forehead, a flattened nasal bridge, a narrow and short trunk, a protuberant abdomen, bilateral postaxial polydactyly and syndactyly of the hands and feet, and micromelic limbs. No facial cleft or genital abnormality was noted. The radiograph was consistent with SRPS III.

CONCLUSION

Polydactyly, micromelia, metaphyseal spurs, widened humeral metaphyses, and shortened ribs can be prominent prenatal ultrasound findings of SRPS III. The present case provides evidence for a correlation of a mutation in the NEK1 gene with SRPS III.

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

The purpose of this article is to describe the use of three-dimensional sonography as an adjuvant to two-dimensional sonography facilitating an earlier and more definitive diagnosis of Jeune and Jeune-like syndromes in the second trimester. We report two cases in which three-dimensional sonography facilitated the diagnosis of these malformations. A diagnosis of Jeune syndrome was made in our first case. Our second case was found to be short-rib polydactyly syndrome Type IV. Three-dimensional skeletal survey visualized short ribs, short limbs, the presence of normal scapulae, and the absence of polydactyly in both cases. Three-dimensional sonography can assist two-dimensional sonography in providing a more accurate display of skeletal anomalies, limb abnormalities, and facial features.

Ellis-van Creveld syndrome: prenatal diagnosis, molecular analysis and genetic counseling

OBJECTIVE

To present the perinatal findings and molecular genetic analysis of two siblings with Ellis-van Creveld (EvC) syndrome.

MATERIALS, METHODS AND RESULTS

A 33-year-old woman, gravida 3, para 1, was referred for genetic counseling at 18 gestational weeks because of recurrent fetal skeletal dysplasia. Two years previously, she had delivered a 1,316-g dead male baby at 28 gestational weeks with a karyotype of 46,XY, postaxial polydactyly of the hands, thoracic narrowness, endocardial cushion defects, transposition of the great arteries, shortening of the long bones, malposition of the toes, and hypoplastic nails. During this pregnancy, prenatal ultrasound at 18 gestational weeks revealed shortening of the long bones (equivalent to 15 weeks), postaxial polydactyly of both hands, thoracic narrowness, and endocardial cushion defects. The pregnancy was subsequently terminated, and a 236-g female fetus was delivered with a karyotype of 46,XX, postaxial polydactyly of the hands, thoracic dysplasia, endocardial cushion defects, shortening of the long bones, and malposition of the toes and hypoplastic nails. The phenotype of each of the two siblings was consistent with EVC syndrome. Molecular analysis of the EVC and EVC2 genes revealed heterozygous mutations in the EVC2 gene. A heterozygous deletion mutation of a 26-bp deletion of c.871-2_894del26 encompassing the junction between intron 7 and exon 8 of the EVC2 gene was found in the mother and two siblings, and a heterozygous nonsense mutation of c.1195C >T, p.R399X in exon 10 of the EVC2 gene was found in the father and two siblings.

CONCLUSION

Prenatal sonographic identification of endocardial cushion defects in association with shortening of the long bones should alert clinicians to the possibility of EvC syndrome and prompt a careful search of hexadactyly of the hands. Molecular analysis of the EVC and EVC2 genes is helpful in genetic counseling in cases with prenatally detected postaxial polydactyly, thoracic narrowness, short limbs and endocardial cushion defects.

NEK1 mutations cause short-rib polydactyly syndrome type majewski

Defects of ciliogenesis have been implicated in a wide range of human phenotypes and play a crucial role in signal transduction and cell-cycle coordination. We used homozygosity mapping in two families with autosomal-recessive short-rib polydactyly syndrome Majewski type to identify mutations in NEK1 as an underlying cause of this lethal osteochondrodysplasia. NEK1 encodes a serine/threonine kinase with proposed function in DNA double-strand repair, neuronal development, and coordination of cell-cycle-associated ciliogenesis. We found that absence of functional full-length NEK1 severely reduces cilia number and alters ciliar morphology in vivo. We further substantiate a proposed digenic diallelic inheritance of ciliopathies by the identification of heterozygous mutations in NEK1 and DYNC2H1 in an additional family. Notably, these findings not only increase the broad spectrum of ciliar disorders, but suggest a correlation between the degree of defective microtubule or centriole elongation and organization and the severity of the resulting phenotype.

Making sense of cilia in disease: the human ciliopathies

Ubiquitous in nature, cilia and flagella comprise nearly identical structures with similar functions. The most obvious example of the latter is motility: driving movement of the organism or particle flow across the epithelial surface in fixed structures. In vertebrates, such motile cilia are evident in the respiratory epithelia, ependyma, and oviducts. For over a century, non-motile cilia have been observed on the surface of most vertebrate cells but until recently their function has eluded us. Gathering evidence now points to critical roles for the mono-cilium in sensing the extracellular environment, and perturbation of this function gives rise to a predictable panoply of clinical problems. We review the common clinical phenotypes associated with ciliopathies and interrogate Online Mendelian Inheritance in Man (OMIM) to compile a comprehensive list of putative disorders in which ciliary dysfunction may play a role.

Diagnosis of short rib polydactyly syndrome type IV (Beemer-Langer syndrome) with cystic hygroma: A case report

Short rib polydactyly syndrome (SRPS) is a very rare congenital autosomal recessive inherited disease, classified into four subtypes. It has distinct imaging findings on prenatal sonography (US) and ancillary findings on both pre- and postnatal examinations may help classify individual cases into one of four subtypes. We report the US findings in a case of SRPS type IV (Beemer-Langer dysplasia) in a male fetus with multiple congenital anomalies, including cystic hygroma. The postnatal ultrasound, radiographic, and postmortem examinations helped to classify the SRPS as type IV. We believe this is the first documented case associating cystic hygroma and polydactyly.

Ciliary abnormalities due to defects in the retrograde transport protein DYNC2H1 in short-rib polydactyly syndrome

The short-rib polydactyly (SRP) syndromes are a heterogeneous group of perinatal lethal skeletal disorders with polydactyly and multisystem organ abnormalities. Homozygosity by descent mapping in a consanguineous SRP family identified a genomic region that contained DYNC2H1, a cytoplasmic dynein involved in retrograde transport in the cilium. Affected individuals in the family were homozygous for an exon 12 missense mutation that predicted the amino acid substitution R587C. Compound heterozygosity for one missense and one null mutation was identified in two additional nonconsanguineous SRP families. Cultured chondrocytes from affected individuals showed morphologically abnormal, shortened cilia. In addition, the chondrocytes showed abnormal cytoskeletal microtubule architecture, implicating an altered microtubule network as part of the disease process. These findings establish SRP as a cilia disorder and demonstrate that DYNC2H1 is essential for skeletogenesis and growth.

PRENATAL DIAGNOSIS OF SKELETAL DYSPLASIAS

Skeletal anomalies occur with a frequency of around 1:500 and can present a diagnostic challenge when detected prenatally. Increasingly more sophisticated imaging such as MRI or CT may elucidate features more easily interpreted by postnatal radiologists. The aetiology of these anomalies is varied and includes aneuploidy, genetic syndromes, skeletal dysplasias, teratogens, disruption and maternal disease, making a multidisciplinary approach to the diagnosis essential. The estimated prevalence of skeletal dysplasias varies from 2–3/10,000 to 4–7/10,000 and diagnosis may require biochemical, cytogenetic, molecular genetic or haematological investigation. Clinical genetic input is often required as the family history or parental examination may yield valuable clues to the diagnosis. This review will briefly describe the normal embryology and sonographic appearances of fetal limb development and go on to suggest a systematic approach to the diagnosis of fetal skeletal dysplasias.

An unclassifiable short rib-polydactyly syndrome with acromesomelic hypomineralization and campomelia in siblings

The short rib-polydactyly (SRP) group are lethal skeletal dysplasias with an autosomal recessive inheritance pattern that can be distinguished on radiological and histological grounds. We report on two consecutive pregnancies complicated by a SRP syndrome with acromesomelic hypomineralization and campomelia that cannot be definitely categorized, yet possesses features of this group of conditions. The skeletal changes observed in both cases included markedly shortened ribs, shortened humeri and femora, limb bowing, absent ossification of the radii, ulnae, tibiae and fibulae, as well as the bony elements of the hands and feet, hypoplastic scapulae and peritoneal calcifications. In one case, the pancreas was abnormal in shape, without a tail and the spleen was not identified. Ectopic splenic tissue and intestinal malrotation were identified and were suggestive of a laterality disorder. Whether these two cases should be considered an atypical form of SRP cannot be completely resolved at this present time and will need to wait on further progress in molecular testing.

Angulated femurs and the skeletal dysplasias: experience of the International Skeletal Dysplasia Registry (1988-2006)

Angulated or bent femur (isolated or associated with other long bone bowing) in the fetus or newborn is relatively common when evaluating patients with skeletal dysplasias. To determine the extent and heterogeneity of disorders associated with angulated or bent femurs, we analyzed cases in the radiographic database (1998-2006) of the International Skeletal Dysplasia Registry (ISDR) and determined which established skeletal dysplasias and genetic syndromes are associated with this finding. The results show that more than 40 distinct disorders with varying frequency (very rare to more commonly occurring disorders) can be associated with bowed/bent/angulated femurs. Sixty-six percent of the cases with angulated femurs belonged to three well described groups of disorders; campomelic disorders (24.4%), thanatophoric dysplasia (23.9%) and osteogenesis imperfecta (OI) (18.1%). With specific emphasis on these, this cross-sectional cohort provides discussion of data on other rare disorders associated with angulated femurs and the importance of the finding relative to its occurrence within a diagnostic group. This study aims to provide differential diagnosis of entities to be considered when a fetus or newborn is found to have congenital bowing/angulation of the femur.

Ellis-van Creveld syndrome

Ellis-van Creveld syndrome (EVC) is a chondral and ectodermal dysplasia characterized by short ribs, polydactyly, growth retardation, and ectodermal and heart defects. It is a rare disease with approximately 150 cases reported worldwide. The exact prevalence is unknown, but the syndrome seems more common among the Amish community. Prenatal abnormalities (that may be detected by ultrasound examination) include narrow thorax, shortening of long bones, hexadactyly and cardiac defects. After birth, cardinal features are short stature, short ribs, polydactyly, and dysplastic fingernails and teeth. Heart defects, especially abnormalities of atrial septation, occur in about 60% of cases. Cognitive and motor development is normal. This rare condition is inherited as an autosomal recessive trait with variable expression. Mutations of the EVC1 and EVC2 genes, located in a head to head configuration on chromosome 4p16, have been identified as causative. EVC belongs to the short rib-polydactyly group (SRP) and these SRPs, especially type III (Verma-Naumoff syndrome), are discussed in the prenatal differential diagnosis. Postnatally, the essential differential diagnoses include Jeune dystrophy, McKusick-Kaufman syndrome and Weyers syndrome. The management of EVC is multidisciplinary. Management during the neonatal period is mostly symptomatic, involving treatment of the respiratory distress due to narrow chest and heart failure. Orthopedic follow-up is required to manage the bones deformities. Professional dental care should be considered for management of the oral manifestations. Prognosis is linked to the respiratory difficulties in the first months of life due to thoracic narrowness and possible heart defects. Prognosis of the final body height is difficult to predict.

Short-Rib-Polydactyly Syndrome Presenting with Increased Nuchal Translucency in a High-Risk Family

Short-rib-polydactyly syndrome represents a group of rare, autosomal recessive, lethal skeletal dysplasias characterized by hypoplastic thorax, short ribs, short limbs, polydactyly, and visceral abnormalities. We describe an affected fetus from a high-risk family presenting with increased nuchal translucency at 13 weeks of pregnancy. The diagnosis was established in the 2nd trimester.

A novel heterozygous deletion in the EVC2 gene causes Weyers acrofacial dysostosis

Weyers acrofacial dysostosis (MIM 193530) is an autosomal dominant disorder clinically characterized by mild short stature, postaxial polydactyly, nail dystrophy and dysplastic teeth. Ellis-van Creveld syndrome (EvC, MIM 225500) is an autosomal recessive disorder with a similar, but more severe phenotype. Mutations in the EVC have been identified in both syndromes. However, the EVC mutations only occur in a small proportion of EvC patients. Recently, mutations in a new gene, EVC2, were found to be associated with other EvC cases. The EVC and EVC2 are located close to each other in a head-to-head configuration and may be functionally related. In this study, we report identification of a novel heterozygous deletion in the EVC2 that is responsible for autosomal dominant Weyers acrofacial dysostosis in a large Chinese family. This constitutes the first report of Weyers acrofacial dysostosis caused by this gene. Hence, the spectrum of malformation syndromes due to EVC2 mutations is further extended. Our data provides conclusive evidence that Weyers acrofacial dysostosis and EvC syndrome are allelic and genetically heterogeneous conditions.

Skeletal dysplasias

This review is intended to help the neonatologist who is asked to see a baby or speak to parents who are expecting a baby with signs of a generalised disturbance of bone growth and/or modelling. In this review, we will: define a skeletal dysplasia; discuss the presenting features of a skeletal dysplasia in pregnancy and the newborn period; suggest a clinical approach to find the correct diagnosis; discuss the management of the neonate with a skeletal dysplasia; summarise the clinical features of the most common dysplasias; outline some pitfalls and difficulties in counselling the parents of the baby; and give information on further sources of information about skeletal dysplasias.

Short rib-polydactyly syndrome

INTRODUCTION

Short rib-polydactyly syndrome (SRPD) is an autosomal recessive, lethal skeletal dysplasia. It is characterized by short limb dwarfism, short ribs with thoracic hypoplasia, polydactyly, and multiple anomalies of major organs.

CASE REPORT

We report a case of SRPD subtype II (Majewski) that was detected in the 36th week of gestation, showing hydropic change, narrow thorax, shortened limbs, protuberant abdomen, micromelia, polydactyly and extremely low set ears, depressed nasal bridge, and cleft palate. The family was informed of the fatal outcome of the condition. Delivery was induced, and the baby died just after the birth.

DISCUSSION

Prenatal diagnosis is established with postmortem radiographic and pathologic examinations.