Raine syndrome: Prenatally identified severe craniofacial phenotype with multisuture synostosis and brain abnormalities associated with variants in FAM20C.

Raine syndrome (MIM 259775) is a rare autosomal recessive disorder, first described by Raine et al. in 1989, with an estimated prevalence of <1/1,000,000. This is due to pathogenic variants in FAM20C characterized by osteosclerosis, typical craniofacial features, and brain calcifications. Here, we report a novel variant in FAM20C, describe a uniquely severe craniofacial and CNS phenotype of Raine syndrome, and correlate it with prenatal findings. Fetal phenotyping was based on ultrasound and MRI. Solo exome sequencing was performed from DNA extracted from postmortem skin biopsy. Targeted parental variant testing was subsequently performed. A homozygous missense variant NM_020223.4 (c.1445 G > A (p.Gly482Glu)) was identified in FAM20C associated with Raine syndrome. The infant had the characteristic dysmorphic features seen in Raine syndrome. He had particularly significant CNS manifestations consisting of multisuture craniosynostosis with protrusion of the brain parenchyma through fontanelles and cranial lacunae. Histological sections of the brain showed marked periventricular gliosis with regions of infarction, hemorrhage, and cavitation with global periventricular leukomalacia. Numerous dystrophic calcifications were diffusely present. Here, we demonstrate the identification of a novel variant in FAM20C in an infant with the characteristic features seen in Raine syndrome. The patient expands the characteristic phenotype of Raine syndrome to include a uniquely severe CNS phenotype, first identified on prenatal imaging.

RASopathies: A significant cause of polyhydramnios?

OBJECTIVE: The aim of the study is to determine the prevalence of RASopathies in a polyhydramnios cohort selected by postnatal medical genetics evaluation. METHODS: In this retrospective study, we reviewed 622 pregnancies with polyhydramnios seen at Lucile Packard Children's Hospital between 2008 and 2017. The findings from 131 cases evaluated by Medical Genetics were included in our final analysis. Genetic testing information was extracted to determine the rate of chromosomal or single gene conditions focusing on the RASopathies. Additional variables collected were: maternal characteristics, ultrasound findings, and the severity and timing of diagnosis of polyhydramnios. RESULTS: Postnatal genetic testing or clinical examination identified a genetic disorder in 63 (48.1%) cases, more than half (n = 33) of which had a single gene condition. Postnatal testing revealed an underlying RASopathy in 15 (11.5%) cases. An underlying RASopathy was significantly associated with the severity and timing of polyhydramnios (p < 0.05). CONCLUSION: Focusing on a selected cohort postnatally evaluated by Medical Genetics, our study identified a chromosomal or genetic disorder in almost half of pregnancies complicated by polyhydramnios. Specifically, an underlying RASopathy was found in 11.5% of cases with 13/15 of these cases having additional ultrasound findings.

Prenatally diagnosed omphalocele: characteristics associated with adverse neonatal outcomes.

OBJECTIVE: To characterize factors associated with adverse neonatal outcomes in prenatally diagnosed omphalocele cases. STUDY DESIGN: Prenatally diagnosed omphalocele cases at a single referral center from 1 January 2009 to 31 December 2017 were retrospectively reviewed. Clinical variables and antenatal imaging measurements were collected. Associations between prenatal and neonatal characteristics and the adverse outcome of death or prolonged length of stay (LOS) were analyzed. RESULTS: Out of 63 fetal cases, 33 were live-born, > 50% had other anomalies, and neonatal mortality was 12%. Adverse outcomes were associated with neonatal variables, including lower median 1-min Apgar score, initial mechanical ventilation, and late-onset sepsis, but not approach to omphalocele closure. With multivariate analysis, death or prolonged LOS was associated only with low lung volumes by fetal MRI (OR 34 (3-422), p = 0.006). CONCLUSION: Low lung volumes by fetal MRI were associated with death or prolonged LOS in neonates with prenatally diagnosed omphalocele and may guide clinicians with counseling families.

Prenatal treatment of ornithine transcarbamylase deficiency.

PURPOSE OF STUDY: Patients with neonatal urea cycle defects (UCDs) typically experience severe hyperammonemia during the first days of life, which results in serious neurological injury or death. Long-term prognosis despite optimal pharmacological and dietary therapy is still poor. The combination of intravenous sodium phenylacetate and sodium benzoate (Ammonul®) can eliminate nitrogen waste independent of the urea cycle. We report attempts to improve outcomes for males with severe ornithine transcarbamylase deficiency (OTCD), a severe X-linked condition, via prenatal intravenous administration of Ammonul and arginine to heterozygous carrier females of OTCD during labor. METHODS USED: Two heterozygote OTCD mothers carrying male fetuses with a prenatal diagnosis of OTCD received intravenous Ammonul, arginine and dextrose-containing fluids shortly before birth. Maintenance Ammonul and arginine infusions and high-caloric enteral nutrition were started immediately after birth. Ammonul metabolites were measured in umbilical cord blood and the blood of the newborn immediately after delivery. Serial ammonia and biochemical analyses were performed following delivery. SUMMARY OF RESULTS: Therapeutic concentrations of Ammonul metabolites were detected in umbilical cord and neonatal blood samples. Plasma ammonia and glutamine levels in the postnatal period were within the normal range. Peak ammonia levels in the first 24-48h were 53mcmol/l and 62mcmol/l respectively. The boys did not experience neurological sequelae secondary to hyperammonemia and received liver transplantation at ages 3months and 5months. The patients show normal development at ages 7 and 3years. CONCLUSION: Prenatal treatment of mothers who harbor severe OTCD mutations and carry affected male fetuses with intravenous Ammonul and arginine, followed by immediate institution of maintenance infusions after delivery, results in therapeutic levels of benzoate and phenylacetate in the newborn at delivery and, in conjunction with high-caloric enteral nutrition, prevents acute hyperammonemia and neurological decompensation. Following initial medical management, early liver transplantation may improve developmental outcome.

Prenatally Diagnosed Cases of Binder Phenotype Complicated by Respiratory Distress in the Immediate Postnatal Period.

Binder phenotype, or maxillonasal dysostosis, is a distinctive pattern of facial development characterized by a short nose with a flat nasal bridge, an acute nasolabial angle, a short columella, a convex upper lip, and class III malocclusion. We report 3 cases of prenatally diagnosed Binder phenotype associated with perinatal respiratory impairment.

46,XY disorders of sex development and congenital diaphragmatic hernia: a case with dysmorphic facies, truncus arteriosus, bifid thymus, gut malrotation, rhizomelia, and adactyly.

The association of 46,XY disorder of sex development (DSD) with congenital diaphragmatic hernia (CDH) is rare, but has been previously described with and without other congenital anomalies. Literature review identified five cases of 46,XY DSD associated with CDH and other congenital anomalies. These five cases share characteristics including CDH, 46,XY karyotype with external female appearing or ambiguous genitalia, cardiac anomalies, and decreased life span. The present case had novel features including truncus arteriosus, bifid thymus, gut malrotation, and limb anomalies consisting of rhizomelia and adactyly. With this case report, we present a review of the literature of cases of 46,XY DSD and CDH in association with multiple congenital abnormalities. This case may represent a unique syndrome of 46,XY DSD and diaphragmatic hernia or a more severe presentation of a syndrome represented in the previously reported cases.

Perinatal features of the RASopathies: Noonan syndrome, cardiofaciocutaneous syndrome and Costello syndrome.

The RASopathies are a family of developmental disorders caused by heritable defects of the RAS/MAPK signaling pathway. While the postnatal presentation of this group of disorders is well known, the prenatal and neonatal findings are less widely recognized. We report on the perinatal presentation of 10 patients with Noonan syndrome (NS), nine with Cardiofaciocutaneous syndrome (CFCS) and three with Costello syndrome (CS), in conjunction with the results of a comprehensive literature review. The majority of perinatal findings in NS, CS, and CFCS are shared: polyhydramnios; prematurity; lymphatic dysplasia; macrosomia; relative macrocephaly; respiratory distress; hypotonia, as well as cardiac and renal anomalies. In contrast, fetal arrhythmia and neonatal hypoglycemia are relatively specific to CS. NS, CS, and CFCS should all be considered as a possible diagnosis in pregnancies with a normal karyotype and ultrasound findings of a RASopathy. Recognition of the common perinatal findings of these disorders should facilitate both their prenatal and neonatal diagnosis.

Clinical whole-exome sequencing: are we there yet?

BACKGROUND: Clinical laboratories began offering whole-exome sequencing in 2011 at a cost between $4,500 and $9,000. Reported detection rates for deleterious mutations range from 25 to 50%. Based on the experience of our clinical genetics service, actual success rates may be lower than estimated rates. We report results from our own experience along with a survey of clinical geneticists to ascertain (i) current success rates for causal gene detection in a clinical setting; (ii) if there are insurance authorization issues; and (iii) if turnaround times quoted by the clinical laboratories are accurate; we also gauge provider opinions toward clinical whole-exome sequencing. METHODS: We reviewed our results and the results of a survey that was electronically distributed to 47 clinical genetics centers. RESULTS: A total of 35 exome reports were available. If all positive results are collated, we observe a success rate of 22.8%. One result incorrectly identified a known benign variant as pathogenic. Some insurers covered all testing, whereas others denied any insurance coverage. Only three (23.1%) of our reports were available within the laboratory's quoted turnaround times. More than 50% of clinicians queried in our survey had not ordered whole-exome sequencing at the current time, many stating concerns regarding interpretation, insurance coverage, and cost. CONCLUSION: Clinical whole-exome sequencing has proven diagnostic utility; however, currently many clinicians have concerns regarding interpretation of results, insurance coverage, and cost.