Short- and long-term outcome following thoracoamniotic shunting for fetal hydrothorax.

OBJECTIVES: To assess short- and long-term outcome in a cohort of fetuses diagnosed with hydrothorax (FHT) which underwent thoracoamniotic shunting in utero, and to examine the antenatal predictors of survival and of survival with normal neurodevelopmental outcome. METHODS: This was a retrospective analysis of 132 fetuses that underwent thoracoamniotic shunting at our center between 1991 and 2014. Data were extracted from hospital obstetric and relevant neonatal intensive care and neonatal developmental follow-up databases. Outcomes included survival to discharge and survival with normal neurodevelopmental outcome beyond 18 months. Information on malformations, syndromes and genetic abnormalities were obtained from antenatal, postnatal and pediatric hospital records or by parent report. We compared pregnancy characteristics among those who survived vs non-survivors and among those with normal neurodevelopmental outcome vs those who were abnormal or died. We explored whether there was a trend in survival over the study period. RESULTS: The mean gestational age at diagnosis of FHT was 25.6 weeks. The fetus was hydropic at diagnosis in 61% of cases, 69% had bilateral effusions and 55% had bilateral shunts inserted. Other diagnoses were present in 24% of cases, two-thirds of which were discovered only postnatally. There were 16 intrauterine and 30 neonatal deaths, with a 65% survival rate overall. The mean gestational age at delivery of liveborns was 35.4 (range, 26.9-41.6) weeks, and 88/116 (76%) were preterm (< 37 weeks). Of 87 liveborn at the treatment center, 75% experienced some respiratory and/or cardiovascular morbidity after birth, many with a lengthy hospital stay (mean, 36 (range, 1-249) days). Overall, 84% of survivors were developmentally normal beyond 18 months and outcomes were better when pleural effusions were isolated, 92% of these cases being neurodevelopmentally normal. There was no trend in survival or neurodevelopmental outcome over time. Despite the presence of FHT and neonatal respiratory issues, most (89%) of the 55 survivors with relevant follow-up had no long-term pulmonary complications. Gestational age at delivery was the only factor independently predictive of both survival and survival with normal neurodevelopmental outcome. CONCLUSIONS: FHT is associated with other pathologies in a quarter of cases and carries a significant risk of prematurity, mortality and neonatal morbidity. The outcome is good in survivors but is best in isolated cases. Predictors of outcome at diagnosis are poor. Future improvement in diagnostics at time of identification of FHT may help to identify those that would benefit most from thoracoamniotic shunting. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Characteristic Cochlear Hypoplasia in Patients with Walker-Warburg Syndrome: A Radiologic Study of the Inner Ear in α-Dystroglycan-Related Muscular Disorders.

BACKGROUND AND PURPOSE: Walker-Warburg syndrome, muscle-eye-brain disease, and Fukuyama congenital muscular dystrophy are α-dystroglycan-related muscular disorders associated with brain malformations and eye abnormalities in which no structural inner ear abnormality has been described radiologically. We collected patients from 6 tertiary pediatric hospitals and reported the radiologic features and frequency of inner ear dysplasias. MATERIALS AND METHODS: Patients previously diagnosed clinicoradiologically with Walker-Warburg syndrome, muscle-eye-brain disease, or Fukuyama congenital muscular dystrophy were included. We recorded the pathogenic variant, when available. Brain MR imaging and/or CT findings were reviewed in consensus, and inner ear anomalies were classified according to previous description in the literature. We then correlated the clinicoradiologic phenotype with the inner ear phenotype. RESULTS: Thirteen patients fulfilled the criteria for the Walker-Warburg syndrome phenotype, 8 for muscle-eye-brain disease, and 3 for Fukuyama congenital muscular dystrophy. A dysplastic cochlea was demonstrated in 17/24. The most frequent finding was a pronounced cochlear hypoplasia type 4 with a very small anteriorly offset turn beyond the normal-appearing basal turn (12/13 patients with Walker-Warburg syndrome and 1/11 with muscle-eye-brain disease or Fukuyama congenital muscular dystophy). Two of 8 patients with muscle-eye-brain disease, 1/3 with Fukuyama congenital muscular dystrophy, and 1/13 with Walker-Warburg syndrome showed a less severe cochlear hypoplasia type 4. The remaining patients without Walker-Warburg syndrome were healthy. The vestibule and lateral semicircular canals of all patients were normal. Cranial nerve VIII was present in all patients with diagnostic MR imaging. CONCLUSIONS: Most patients with the severe α-dystroglycanopathy Walker-Warburg syndrome phenotype have a highly characteristic cochlear hypoplasia type 4. Patients with the milder variants, muscle-eye-brain disease and Fukuyama congenital muscular dystrophy, more frequently have a normal cochlea or milder forms of hypoplasia.

Long-term postnatal outcome of fetuses with prenatally suspected septo-optic dysplasia.

OBJECTIVES: Septo-optic dysplasia (SOD) is a clinical syndrome characterized by varying combinations of optic nerve hypoplasia, pituitary gland hypoplasia and abnormal cavum septi pellucidi. It is suspected on prenatal imaging when there is non-visualization or hypoplasia of the septal leaflets. Long-term postnatal outcomes of fetuses with prenatally suspected SOD have been documented poorly. The aims of this study were to describe the natural history of deficient septal leaflets, to quantify the incidence of postnatally confirmed SOD and to document the visual, endocrine and long-term neurodevelopmental outcomes of these infants. METHODS: This was an observational retrospective study of all fetuses with prenatal imaging showing isolated septal agenesis, assessed at a single tertiary center over an 11-year period. Pregnancy, delivery and neonatal outcomes and pre- and postnatal imaging findings were reviewed. Neonatal evaluations or fetal autopsy reports were assessed for confirmation of SOD. Ophthalmologic, endocrine, genetic and long-term developmental evaluations were assessed. Imaging findings and outcome were compared between infants with and those without postnatally confirmed SOD. RESULTS: Of 214 fetuses presenting with septal absence on prenatal ultrasound and magnetic resonance imaging (MRI), 18 (8.4%) were classified as having suspected isolated septal agenesis suspicious for SOD. Uniform prenatal MRI findings in cases with suspected SOD included remnants of the leaflets of the cavum septi pellucidi, fused forniceal columns, normal olfactory bulbs and tracts and a normal optic chiasm. Twelve fetuses were liveborn and five (27.8%) had postnatally confirmed SOD. Only two of these five fetuses had additional prenatal imaging features (pituitary cyst, microphthalmia and optic nerve hypoplasia) supporting a diagnosis of SOD. The other three confirmed SOD cases had no predictive prenatal or postnatal imaging findings that reliably differentiated them from cases without confirmed SOD. Visual and endocrine impairments were present in two (40%) and four (80%) cases with confirmed SOD, respectively. In those with visual and/or endocrine impairment, developmental delay (median age at follow-up, 2.5 (interquartile range, 2.5-7.0) years) was common (80%) and mostly severe. Neonates with isolated septal agenesis and a lack of visual or endocrine abnormalities to confirm SOD had normal development. CONCLUSIONS: Only a quarter of fetuses with isolated septal agenesis suggestive of SOD will have postnatal confirmation of the diagnosis. Clinical manifestations of SOD are variable, but neurodevelopmental delay may be more prevalent than thought formerly. © 2020 Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Microarray and RASopathy-disorder testing in fetuses with increased nuchal translucency.

OBJECTIVES: To determine the incidence of chromosomal abnormalities, submicroscopic chromosomal abnormalities and RASopathy-disorder (RD) pathogenic variants in a cohort of pregnancies with nuchal translucency thickness (NT) ≥ 3.5 mm, and to propose a clinical protocol for surveillance of this group of patients. METHODS: This was a retrospective chart review of patients referred to The Prenatal Diagnosis and Medical Genetics Program at Mount Sinai Hospital between January 2013 and December 2015, due to NT ≥ 3.5 mm, who underwent chorionic villus sampling or amniocentesis. Patients underwent extensive genetic counseling prior to invasive procedures and testing. Quantitative fluorescence polymerase chain reaction (QF-PCR) was performed as the first-line test for aneuploidy. If the result was negative, patients underwent karyotyping and/or chromosomal microarray analysis (CMA), and if the findings were normal, they had testing for RD pathogenic variants, which included nine known genes. Patients also underwent detailed fetal ultrasound examinations and echocardiography, performed by expert operators. RESULTS: A total of 226 eligible patients were identified. In 116/226 (51.3%) patients, QF-PCR identified a chromosomal aneuploidy. The remaining 110/226 (48.7%) patients had further genetic testing. Karyotyping/CMA detected an abnormal/pathogenic cytogenetic result in 9/110 (8.2%) patients, as well as five variants of unknown significance (VOUS). RD testing yielded three pathogenic variants (3/103), giving a detection rate of 2.9%, and one VOUS. The optimal NT cut-off for RD screening was 7.9 mm in this population. In 92/110 (83.6%) patients, the genetic investigations were normal. Of these pregnancies, an early (14-16 weeks' gestation) detailed fetal ultrasound examination identified a structural abnormality in 24 (26.1%), 15 (16.3%) had an abnormal detailed ultrasound examination at 18-22 weeks' gestation and fetal echocardiography showed a cardiac abnormality in nine (9.8%). The birth outcome in the 83 pregnancies that had normal genetic investigations and known outcome included seven (8.4%) cases of termination of pregnancy, seven (8.4%) cases of intrauterine fetal death and 69 (83.1%) cases of live birth. Nine (9.8%) patients were lost to follow-up. CONCLUSIONS: Both CMA and molecular testing for RD are important investigations in pregnancies with NT ≥ 3.5 mm. The use of genetic testing combined with fetal ultrasound examination provides valuable information that can influence pregnancy outcome, and provide recurrence risks, in this patient population. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Disability Experiences and Perspectives Regarding Reproductive Decisions, Parenting, and the Utility of Genetic Services: a Qualitative Study.

Genetic counselors adopt seemingly contradictory roles: advocating for individuals with genetic conditions while offering prenatal diagnosis and the option of selective termination to prevent the birth of a child with a disability. This duality contributes to the tension between the disability and clinical genetics communities. Varying opinions exist amongst the disability community: some value genetic services while others are opposed. However, there is limited research exploring the opinions of individuals with a disability regarding issues related to reproduction and genetic services in the context of personal experience. This exploratory qualitative study involved interviews with seven women and three men who self-identify as having a disability. We sought to gain their perspectives on experiences with disability, thoughts about reproduction and parenting, and perceptions of genetic services. Transcripts of the interviews were analyzed thematically using qualitative content analysis. Data analysis showed that societal views of disability affected the lived experience and impacted reproductive decision-making for those with a disability. It also showed differing interest in genetic services. Concerns about the perceived collective implications of genetic services were also raised. These findings contribute to the understanding of the disability perspective toward reproductive decision-making and genetic services. A further goal is to promote a meaningful dialogue between the genetics and disability communities, with the potential to enhance the genetic and reproductive care provided to individuals with disabilities.

Characteristic MR Imaging Findings of the Neonatal Brain in RASopathies.

BACKGROUND AND PURPOSE: Neuroimaging features in neonates with RASopathies are rarely reported, and to date, there are no neuroimaging studies conducted in this population. Our aim was to investigate the occurrence of supratentorial and posterior fossa abnormalities on brain MRIs of neonates with a RASopathy. MATERIALS AND METHODS: An observational case-control study of neonates with a confirmed RASopathy was conducted. The presence of an intraventricular and/or parenchymal hemorrhage and punctate white matter lesions and assessments of the splenium of the corpus callosum, gyrification of the cortical gray matter, and enlargement of the extracerebral space were noted. The vermis height, transverse cerebellar diameter, cranial base angle, tentorial angle, and infratentorial angle were measured. RESULTS: We reviewed 48 brain MR studies performed at 3 academic centers in 3 countries between 2009 and 2017. Sixteen of these infants had a genetically confirmed RASopathy (group 1), and 32 healthy infants were enrolled as the control group (group 2). An increased rate of white matter lesions, extracerebral space enlargement, simplification of the cortical gyrification, and white matter abnormalities were seen in group 1 (P < .001, for each). The vermis height of patients was significantly lower, and tentorial and infratentorial angles were significantly higher in group 1 (P = .01, P < .001, and P = .001, respectively). CONCLUSIONS: Neonates with a RASopathy had characteristic structural and acquired abnormalities in the cortical gray matter, white matter, corpus callosum, cerebellum, and posterior fossa. This study provides novel neuroimaging findings on supratentorial and posterior fossa abnormalities in neonates with a RASopathy.

Novel KIAA0753 mutations extend the phenotype of skeletal ciliopathies.

The skeletal ciliopathies are a heterogeneous group of disorders with a significant clinical and genetic variability and the main clinical features are thoracic hypoplasia and short tubular bones. To date, 25 genes have been identified in association with skeletal ciliopathies. Mutations in the KIAA0753 gene have recently been associated with Joubert syndrome (JBTS) and orofaciodigital (OFD) syndrome. We report biallelic pathogenic variants in KIAA0753 in four patients with short-rib type skeletal dysplasia. The manifestations in our patients are variable and ranging from fetal lethal to viable and moderate skeletal dysplasia with narrow thorax and abnormal metaphyses. We demonstrate that KIAA0753 is expressed in normal fetal human growth plate and show that the affected fetus, with a compound heterozygous frameshift and a nonsense mutation in KIAA0753, has an abnormal proliferative zone and a broad hypertrophic zone. The importance of KIAA0753 for normal skeletal development is further confirmed by our findings that zebrafish embryos homozygous for a nonsense mutation in kiaa0753 display altered cartilage patterning.

Loss of the arginine methyltranserase PRMT7 causes syndromic intellectual disability with microcephaly and brachydactyly.

Post-translational protein modifications exponentially expand the functional complement of proteins encoded by the human genome. One such modification is the covalent addition of a methyl group to arginine or lysine residues, which is used to regulate a substantial proportion of the proteome. Arginine and lysine methylation are catalyzed by protein arginine methyltransferase (PRMTs) and protein lysine methyltransferase proteins (PKMTs), respectively; each methyltransferase has a specific set of target substrates. Here, we report a male with severe intellectual disability, facial dysmorphism, microcephaly, short stature, brachydactyly, cryptorchidism and seizures who was found to have a homozygous 15,309 bp deletion encompassing the transcription start site of PRMT7, which we confirmed is functionally a null allele. We show that the patient's cells have decreased levels of protein arginine methylation, and that affected proteins include the essential histones, H2B and H4. Finally, we demonstrate that patient cells have altered Wnt signaling, which may have contributed to the skeletal abnormalities. Our findings confirm the recent disease association of PRMT7, expand the phenotypic manifestations of this disorder and provide insight into the molecular pathogenesis of this new condition.

Chitayat syndrome: hyperphalangism, characteristic facies, hallux valgus and bronchomalacia results from a recurrent c.266A>G p.(Tyr89Cys) variant in the ERF gene.

BACKGROUND: In 1993, Chitayat et al., reported a newborn with hyperphalangism, facial anomalies, and bronchomalacia. We identified three additional families with similar findings. Features include bilateral accessory phalanx resulting in shortened index fingers; hallux valgus; distinctive face; respiratory compromise. OBJECTIVES: To identify the genetic aetiology of Chitayat syndrome and identify a unifying cause for this specific form of hyperphalangism. METHODS: Through ongoing collaboration, we had collected patients with strikingly-similar phenotype. Trio-based exome sequencing was first performed in Patient 2 through Deciphering Developmental Disorders study. Proband-only exome sequencing had previously been independently performed in Patient 4. Following identification of a candidate gene variant in Patient 2, the same variant was subsequently confirmed from exome data in Patient 4. Sanger sequencing was used to validate this variant in Patients 1, 3; confirm paternal inheritance in Patient 5. RESULTS: A recurrent, novel variant NM_006494.2:c.266A>G p.(Tyr89Cys) in ERF was identified in five affected individuals: de novo (patient 1, 2 and 3) and inherited from an affected father (patient 4 and 5). p.Tyr89Cys is an aromatic polar neutral to polar neutral amino acid substitution, at a highly conserved position and lies within the functionally important ETS-domain of the protein. The recurrent ERF c.266A>C p.(Tyr89Cys) variant causes Chitayat syndrome. DISCUSSION: ERF variants have previously been associated with complex craniosynostosis. In contrast, none of the patients with the c.266A>G p.(Tyr89Cys) variant have craniosynostosis. CONCLUSIONS: We report the molecular aetiology of Chitayat syndrome and discuss potential mechanisms for this distinctive phenotype associated with the p.Tyr89Cys substitution in ERF.

Validation of the finding of hypertrophy of the clava in infantile neuroaxonal dystrophy/PLA2G6 by biometric analysis.

INTRODUCTION: Infantile neuroaxonal dystrophy (INAD), an autosomal recessive neurodegenerative disorder due to PLA2G6 mutation, is classified both as a PLA2G6-associated neurodegeneration (PLAN) disorder and as one of the neurodegeneration with brain iron accumulation (NBIA) disorders. Age of onset and clinical presentation in INAD is variable. Typically described imaging features of cerebellar atrophy, cerebellar cortex bright FLAIR signal, and globus pallidus iron deposition are variable or late findings. We characterize clinical and neuroimaging phenotypes in nine children with confirmed PLA2G6 mutations and show a useful imaging feature, clava hypertrophy, which may aid in earlier identification of patients. Measurements of the clava confirm actual enlargement, rather than apparent enlargement due to volume loss of the other brain stem structures. METHODS: A retrospective clinical and MRI review was performed. Brain stem measurements were performed and compared with age-matched controls. RESULTS: We identified nine patients, all with novel PLA2G6 gene mutations. MRI, available in eight, showed clava hypertrophy, regardless of age or the absence of other more typically described neuroimaging findings. Brain autopsy in our cohort confirmed prominent spheroid bodies in the clava nuclei. CONCLUSION: Clava hypertrophy is an important early imaging feature which may aid in indentification of children who would benefit from specific testing for PLA2G6 mutations.

Analysis of tissue from products of conception and perinatal losses using QF-PCR and microarray: A three-year retrospective study resulting in an efficient protocol.

OBJECTIVE: To evaluate the performance of a laboratory protocol for direct genetic analysis performed on tissues obtained from miscarriages, stillbirth and postnatal death. METHODS: Samples were collected between July 1st, 2011 and June 30th, 2014. QF-PCR analysis was the initial test followed by aCGH analysis performed on the normal QF-PCR specimens. RESULTS: Of the 1195 submitted specimens, a total of 1071 samples were confirmed as true fetal. The failure rate was 1.4%. Of those, 30.8% yielded abnormal results. Of the latter, 57.6% had abnormal QF-PCR and 42.4% had abnormal microarray result. Autosomal trisomies were detected in 61.2%, triploidy in 7.6%, monosomy X in 9.1%, sex-chromosome aneuploidy (apart from monosomy X) in 1.5%, molar pregnancies in 5.8% and copy number variants in 14.2% including microdeletions/microduplications and cryptic unbalanced rearrangements. The highest diagnostic yield was observed in the 1st trimester specimens at 67.6%. We confirmed that maternal age correlates with the likelihood of autosomal trisomies but not with triploidy, sex chromosome aneuploidies, molar pregnancy, or CNVs. CONCLUSION: An efficient laboratory protocol, based on QF-PCR and aCGH of uncultured cells has replaced standard cytogenetic analysis in testing of tissue from all pregnancy losses in our center and resulted in reduced test failure rate and increased diagnostic yield.

Utility of whole-exome sequencing for those near the end of the diagnostic odyssey: time to address gaps in care.

An accurate diagnosis is an integral component of patient care for children with rare genetic disease. Recent advances in sequencing, in particular whole-exome sequencing (WES), are identifying the genetic basis of disease for 25-40% of patients. The diagnostic rate is probably influenced by when in the diagnostic process WES is used. The Finding Of Rare Disease GEnes (FORGE) Canada project was a nation-wide effort to identify mutations for childhood-onset disorders using WES. Most children enrolled in the FORGE project were toward the end of the diagnostic odyssey. The two primary outcomes of FORGE were novel gene discovery and the identification of mutations in genes known to cause disease. In the latter instance, WES identified mutations in known disease genes for 105 of 362 families studied (29%), thereby informing the impact of WES in the setting of the diagnostic odyssey. Our analysis of this dataset showed that these known disease genes were not identified prior to WES enrollment for two key reasons: genetic heterogeneity associated with a clinical diagnosis and atypical presentation of known, clinically recognized diseases. What is becoming increasingly clear is that WES will be paradigm altering for patients and families with rare genetic diseases.

NSD1 mutations generate a genome-wide DNA methylation signature.

Sotos syndrome (SS) represents an important human model system for the study of epigenetic regulation; it is an overgrowth/intellectual disability syndrome caused by mutations in a histone methyltransferase, NSD1. As layered epigenetic modifications are often interdependent, we propose that pathogenic NSD1 mutations have a genome-wide impact on the most stable epigenetic mark, DNA methylation (DNAm). By interrogating DNAm in SS patients, we identify a genome-wide, highly significant NSD1(+/-)-specific signature that differentiates pathogenic NSD1 mutations from controls, benign NSD1 variants and the clinically overlapping Weaver syndrome. Validation studies of independent cohorts of SS and controls assigned 100% of these samples correctly. This highly specific and sensitive NSD1(+/-) signature encompasses genes that function in cellular morphogenesis and neuronal differentiation, reflecting cardinal features of the SS phenotype. The identification of SS-specific genome-wide DNAm alterations will facilitate both the elucidation of the molecular pathophysiology of SS and the development of improved diagnostic testing.

Diagnostic utility of microarray testing in pregnancy loss.

OBJECTIVES: To determine the frequency of clinically significant chromosomal abnormalities identified by chromosomal microarray in pregnancy losses at any gestational age and to compare microarray performance with that of traditional cytogenetic analysis when testing pregnancy losses. METHODS: Among 535 fetal demise specimens of any gestational age, clinical microarray-based comparative genomic hybridization (aCGH) was performed successfully on 515, and a subset of 107 specimens underwent additional single nucleotide polymorphism (SNP) analysis. RESULTS: Overall, clinically significant abnormalities were identified in 12.8% (64/499) of specimens referred with normal or unknown karyotypes. Detection rates were significantly higher with earlier gestational age. In the subset with normal karyotype, clinically significant abnormalities were identified in 6.9% (20/288). This detection rate did not vary significantly with gestational age, suggesting that, unlike aneuploidy, the contribution of submicroscopic chromosomal abnormalities to fetal demise does not vary with gestational age. In the 107 specimens that underwent aCGH and SNP analysis, seven cases (6.5%) had abnormalities of potential clinical significance detected by the SNP component, including female triploidy. aCGH failed to yield fetal results in 8.3%, which is an improvement over traditional cytogenetic analysis of fetal demise specimens. CONCLUSIONS: Both the provision of results in cases in which karyotype fails and the detection of abnormalities in the presence of a normal karyotype demonstrate the increased diagnostic utility of microarray in pregnancy loss. Thus, chromosomal microarray testing is a preferable, robust method of analyzing cases of pregnancy loss to better delineate possible genetic etiologies, regardless of gestational age.

The sooner the better: Genetic testing following ovarian cancer diagnosis.

OBJECTIVE: As treatment based genetic testing becomes a reality, it is important to assess the attitudes and preferences of women newly diagnosed with ovarian cancer regarding genetic testing. The objective of this study was to determine when women with a diagnosis of high grade serous ovarian cancer would prefer to undergo genetic testing and factors that influence this preference. METHODS: Women over 18years of age with a known diagnosis of high grade serous ovarian cancer diagnosed between October 2010-2013 were identified via the Princess Margaret Cancer Center Registry. Participants completed a questionnaire, which obtained preferences and attitudes towards genetic testing, cancer history, and demographic information. RESULTS: 120 of the 355 women identified (33.8%) completed the questionnaires. The median age at time of ovarian cancer diagnosis was 57years (range 35-84). The majority of participants in this study were offered (94.6%) and pursued (84.8%) genetic testing. In this cohort, testing was most frequently offered at diagnosis (41.8%) or during treatment (19.1%). In this study, women with high grade serous ovarian cancer felt that genetic testing should be offered before or at the time of diagnosis (67.8%). Having a family history of breast or ovarian cancer was significantly (p=0.012) associated with preferring genetic testing at an earlier time point in the disease course. CONCLUSIONS: Our results demonstrate that women with high grade serous ovarian cancer acknowledge the personal and clinical utility of genetic testing and support test implementation at the time of cancer diagnosis.

Foetal "black bone" MRI: utility in assessment of the foetal spine.

OBJECTIVE: Foetal CT has recently been added to the foetal imaging armamentarium, but this carries with it the risks of ionizing radiation, both to the mother and the foetus. Foetal "black bone" MRI is a new technique that allows assessment of the foetal skeleton without the risk of exposure to ionizing radiation and is a potential new sequence in foetal MRI examination. METHODS: Retrospective review of all foetal MRI studies over the past 4- to 5-year period identified 36 cases where susceptibility weighted imaging was used. Cases were selected from this group to demonstrate the potential utility of this sequence. RESULTS: This sequence is most frequently useful not only in the assessment of spinal abnormalities, most commonly the bony abnormalities in myelomeningocele, but also in cases of scoliosis, segmentation anomalies and sacrococcygeal teratoma. CONCLUSION: Although the utility of this sequence is still being evaluated, it provides excellent contrast between the mineralized skeleton and surrounding soft tissues compared with standard half Fourier acquisition single-shot turbo-spin echo sequences. Further assessment is required to determine whether black bone MRI can more accurately evaluate the level of bony defect in spina bifida aperta, an important prognostic factor. Potential further uses include the assessment of skeletal dysplasias, evaluation of the skull base and craniofacial skeleton in certain congenital anomalies and the post-mortem evaluation of the foetal skeleton potentially obviating the need for necropsy. ADVANCES IN KNOWLEDGE: Foetal black bone MRI can be performed using susceptibility weighted imaging and allows better demonstration of the mineralized skeleton compared with standard sequences.

Hypotrichosis-lymphedema-telangiectasia-renal defect associated with a truncating mutation in the SOX18 gene.

SOX18 mutations in humans are associated with both recessive and dominant hypotrichosis-lymphedema-telangiectasia syndrome (HLTS). We report two families with affected children carrying a SOX18 mutation: a living patient and his stillborn brother from Canada and a Belgian patient. The two living patients were diagnosed with HLTS and DNA analysis for the SOX18 gene showed that both had the identical heterozygous C > A transversion, resulting in a pre-mature truncation of the protein, lacking the transactivation domain. Both living patients developed renal failure with severe hypertension in childhood for which both underwent renal transplantation. To our best knowledge this is the first report of renal failure associated with heterozygous mutations in the SOX18 gene. We conclude that this specific mutation results in a new, autosomal dominant condition and propose the acronym HLT-renal defect syndrome for HLTRS.

De novo WNT5A-associated autosomal dominant Robinow syndrome suggests specificity of genotype and phenotype.

Robinow Syndrome (RS), a rare skeletal dysplasia syndrome, is characterized by dysmorphic features resembling a fetal face, mesomelic limb shortening, hypoplastic external genitalia in males, and renal and vertebral anomalies. Both autosomal dominant and autosomal recessive patterns of inheritance have been reported. Since the description of autosomal dominant Robinow Syndrome (ADRS; OMIM 180700) in 1969 by Meinhard Robinow and colleagues, the molecular etiology remained elusive until only recently. WNT5A was proposed to be the candidate gene for ADRS, as mutations were found in two affected families, one of those being the originally described index family. We report three families with RS caused by novel heterozygous WNT5A mutations, which were confirmed in the first family by whole exome sequencing, and in all by Sanger sequencing. To our knowledge, this is the largest number of published families with ADRS in whom a WNT5A mutation was identified. Families 1 and 2 are the first cases showing de novo inheritance in the affected family members and thus strengthen the evidence for WNT5A as the causative gene in ADRS. Finally, we propose WNT5A mutation specificity in ADRS, which may affect interactions with other proteins in the Wnt pathway.