Upgrading an intronic TMEM67 variant of unknown significance to likely pathogenic through RNA studies and community data sharing.

FETAL PHENOTYPE: A couple of Ashkenazi Jewish descent was referred for an early anatomy scan at 14 + 2 weeks of gestation following a previous pregnancy termination due to posterior encephalocele and enlarged kidneys. The index pregnancy was also positive for several fetal abnormalities, including enlarged kidneys with cystic dysplasia and abnormal cerebellar morphology highly suggestive of Joubert syndrome. GENETIC DIAGNOSTIC TEST PERFORMED, RESULT, AND INTERPRETATION: Trio exome sequencing revealed compound heterozygosity for variants in the TMEM67 gene: a known pathogenic maternally inherited variant found in trans with a paternal intronic variant of unknown significance. RNA analysis revealed that the intronic variant creates a cryptic acceptor splice site in intron 12, leading to the insertion of 22 bp and causing a frameshift with a premature stop codon. This analysis enabled the reclassification of the intronic variant to likely pathogenic. IMPLICATIONS AND NOVELTY: This information empowered the couple to make informed reproductive choices and opt for preimplantation genetic testing (PGT) for future pregnancies.

L1CAM variants cause two distinct imaging phenotypes on fetal MRI.

Data on fetal MRI in L1 syndrome are scarce with relevant implications for parental counseling and surgical planning. We identified two fetal MR imaging patterns in 10 fetuses harboring L1CAM mutations: the first, observed in 9 fetuses was characterized by callosal anomalies, diencephalosynapsis, and a distinct brainstem malformation with diencephalic-mesencephalic junction dysplasia and brainstem kinking. Cerebellar vermis hypoplasia, aqueductal stenosis, obstructive hydrocephalus, and pontine hypoplasia were variably associated. The second pattern observed in one fetus was characterized by callosal dysgenesis, reduced white matter, and pontine hypoplasia. The identification of these features should alert clinicians to offer a prenatal L1CAM testing.

A unique brain germinal matrix involvement in cytomegalovirus infected fetuses: A retrospective neurosonographic analysis with outcome correlation.

OBJECTIVE: To study the clinical significance of brain germinal matrix (GM) changes in cytomegalovirus (CMV) infected fetuses. METHOD: This is a retrospective analysis. Group A; isolated GM finding, with or without lenticulostriatal vasculopathy (LSV). Group B; non-isolated lesion. Amniocentesis, urinalysis, postnatal US and developmental assessment, were obtained. RESULTS: Group A and B included 18 and four fetuses, respectively. In group A, mean fetal age at diagnosis was 34.3 weeks (31-38 weeks). In 15/18 (83.3%), the lesion was bilateral and LSV was present in 8/18 (44.4%). Small cysts appeared inside the lesion in 5/18 (27.7%). MRI was normal in 8/18 (44.4%). Subtle or inconclusive findings were reported in the remaining fetuses. Brain ultrasound was normal in 10/18 (55.5%) of newborns. In the remaining, caudothalamic cyst with or without LSV, or isolated LSV were found. All newborns are developing normally at a mean follow-up age of 33.3 months (+/- 19.6 moths). In group B, all four patients requested for termination of pregnancy. CONCLUSION: Fetal CMV infection may cause focal GM changes, frequently accompanied by LSV, late in pregnancy. These changes may be isolated, or as part of a more generalized brain damage. When isolated, favorable prognosis is expected.

Walker-Warburg syndrome and tectocerebellar dysraphia: A novel association caused by a homozygous DAG1 mutation.

OBJECTIVES: To elaborate the imaging phenotype associated with a homozygous c.743C > del frameshift mutation in DAG1 leading to complete absence of both α- and ß-dystroglycan previously reported in a consanguineous Israeli-Arab family. METHODS: We analyzed prenatal and postnatal imaging data of patients from a consanguineous Israeli-Arab kindred harboring the DAG1 mutation. RESULTS: The imaging studies (fetal ultrasound, CT scan and postnatal MRI) demonstrated: flat cortex (abnormally thick with irregular pebbled cortical-white matter border on MRI), hydrocephalus, scattered small periventricular heterotopia and subependymal hemorrhages and calcifications, z-shaped brainstem, and in addition an occipital encephalocele, vermian agenesis, and an elongated and thick tectum (tectocerebellar dysraphia). CONCLUSIONS: The novel association of cobblestone malformation with tectocerebellar dysraphia as part of WWS is characteristic of the homozygous c.743C > del frameshift mutation in the DAG1 gene.

Unique Imaging Features Enabling the Prenatal Diagnosis of Developmental Venous Anomalies: A Persistent Echogenic Brain Lesion Drained by a Collecting Vein in Contrast with Normal Brain Parenchyma on MRI.

OBJECTIVE: To describe the prenatal imaging features enabling diagnosis of developmental venous anomalies (DVA). METHODS: Four fetuses with unexplained persistent echogenic parenchymal brain lesions were studied. The evaluation included dedicated neurosonography, fetal MRI, serology for intrauterine infection, screening for coagulation abnormalities, and chromosomal microarray. Postnatal neurodevelopmental follow-up or autopsy results were assessed. RESULTS: DVA presented as very slowly growing echogenic brain lesions without cystic components, calcifications, or structural changes on otherwise normal neurosonographic scans performed at 2- to 3-week intervals. A specific Doppler feature was a collecting vein draining the echogenic parenchyma. Fetal brain MRI depicted normal anatomy on half-Fourier acquisition single-shot turbo spin-echo and diffusion-weighted imaging. The rest of the evaluation was normal. CONCLUSIONS: In cases with a persistent, parenchymal echogenic lesion without clastic or structural changes, DVA should be considered. Demonstration of a collecting vein draining the lesion and normal brain anatomy on MRI confirm the diagnosis.