Prenatally diagnosed periventricular nodular heterotopia: Further delineation of the imaging phenotype and outcome

Relationship between prenatal ultrasound signs and genetic abnormalities for fetal malformations of cortical development

To explore the relationship between ultrasound signs of suspected fetal malformation of cortical development (MCD) and genetic MCD.The retrospective study involved fetuses with one of the following 10 neurosonography (NSG) signs: (A) abnormal development of the Sylvian fissure; (B) delayed achievement of cortical milestones; (C) premature or aberrant appearance of sulcation; (D) irregular border of the ventricular wall or irregular shape of the ventricle; (E) abnormal shape or orientation of the sulci; (F) hemispheric asymmetry; (G) non-continuous cerebral cortex; (H) intraparenchymal echogenic nodules; (I) persistent ganglionic eminence (GE) or GE cavitation; (J) abnormal cortical lamination.95 fetuses were included in the study. Chromosomal microarray (CMA) combined with exome sequencing (ES) was available in 40 fetuses, CMA was abnormal in nine and ES in 22. Sign C (7/7, 100%), sign H (2/2, 100%), sign A (18/19, 94.7%), and sign B (12/13, 92.3%) were the signs leading to the highest probability of genetic MCD. The incidence of genetic MCD for sign E, sign I, and sign D was 66.7-73.7%. Only one or none of the fetuses with sign J, sign F, or sign G underwent CMA+ES. The signs in the fetuses with FGFR3, CCND2, FLNA, or TSC2 mutations had the expected features. The other fetuses with different gene mutations showed several non-specific NSG signs.Several reliable signs for genetic MCD can be detected by NSG, and the probability varies with different signs. Most signs are not associated with a specific gene. Therefore, CMA combined with ES is preferred.

Prenatal assessment of brain malformations on neuroimaging: an expert panel review

Brain malformations represent a heterogeneous group of abnormalities of neural morphogenesis, often associated with aberrations of neuronal connectivity and brain volume. Prenatal detection of brain malformations requires a clear understanding of embryology and developmental morphology through the various stages of gestation. This expert panel review is written with the central aim of providing an easy-to-understand road map to improve prenatal detection and characterization of structural malformations based on the current understanding of normal and aberrant brain development. For every developmental stage, the utility of each available neuroimaging modality, including prenatal multiplanar neuro sonography, anatomical MRI and advanced MRI techniques, as well as further insights from post-mortem imaging, has been highlighted.

A familial case of diffuse periventricular nodular heterotopia identified prenatally: Filamin A defect as the probable cause

Periventricular nodular heterotopia (PNH) is a neuronal migration defect characterized by the presence of ectopic grey matter nodules adjacent to the walls of the lateral ventricles. The main genetic etiology of PNH are variants in the Filamin A gene (FLNA, MIM #300049), located in the X chromosome. It affects mostly females (embryonic lethality in males), with about 50% of cases inherited from healthy mothers or with a mild phenotype. It is associated with epilepsy (75%-90%), cardiovascular (65%) and pulmonary pathologies (25%). A 28-year-old primigravida was referred for prenatal care in obstetrics department because of personal history of obliterative bronchiolitis. She has a family history of asthma (mother and sister) and adulthood-onset epilepsy (father). The pregnancy was uneventful up to 20 weeks and 3 days when bilateral periventricular irregularities and mega cisterna magna were identified on ultrasound in a female fetus. Neurosonography was performed, which led to the hypothesis of diffuse PNH, supported by MRI. The hypothesis of PNH associated to the FLNA gene was made. Brain MRI on the pregnant woman was requested, which confirmed a similar pattern of PNH. The arrayCGH (PerkinElmer, Prenatal filter 37K) was normal, and whole exome sequencing identified the likely pathogenic c.1554del p.(Val519fs*) variant in the FLNA gene. We present a case of X-linked hereditary PNH that highlights the value of fetal neurosonography in making a putative diagnosis. The diagnosis was supported by MRI in both fetus and mother. The investigation was supplemented by genetic studies, which confirmed the diagnosis.

Prenatal Imaging of Supratentorial Fetal Brain Malformation

This review article provides a comprehensive overview of fetal MR imaging in supratentorial cerebral malformations. It emphasizes the importance of fetal MR imaging as an adjunct diagnostic tool used alongside ultrasound, improving the detection and characterization of prenatal brain abnormalities. This article reviews a spectrum of cerebral malformations, their MR imaging features, and the clinical implications of these findings. Additionally, it outlines the growing importance of fetal MR imaging in the context of perinatal care.

Diffuse interstitial lung disease in a male fetus with periventricular nodular heterotopia and filamin A mosaic variant

BACKGROUND

Most periventricular nodular heterotopias (PNHs) are associated with a mutation in the filamin A (FLNA) gene in Xq28. This condition is associated with cardiovascular malformations, connective tissue abnormalities, epilepsy, and intellectual deficiency of varying severity.

MATERIALS AND METHODS

We report a new FLNA gene mutation in a male patient associated with PNH and diffuse interstitial lung disease.

RESULTS

A 23-year-old woman was referred at 31 gestational weeks to evaluate a suspected mega cisterna magna and ventricular septal defect with atrioventricular valve alignment in a male fetus. The fetal magnetic resonance imaging showed PNH associated with corpus callosum dysgenesis and a mega cisterna magna. At 2 months of age, the infant was diagnosed with severe respiratory distress with hypoxemia. A chest CT scan demonstrated a diffuse interstitial lung pattern with emphysema, multiple atelectasis foci, and signs of pulmonary hypertension. Rapid worsening led to his death at 4 months. Targeted sequencing of the FLNA gene identified a de novo hemizygous variant in 75% mosaic in lymphocyte cells, resulting in incomplete FLNA function loss.

DISCUSSION & CONCLUSION

On the diagnosis of antenatal PNH, the possibility of such lung involvement should be considered in the prognostic evaluation during prenatal counseling.

Phenotypic manifestations in FLNA-related periventricular nodular heterotopia: a case report and review of the literature

Periventricular nodular heterotopia (PVNH) is an X-linked disease caused by loss-of-function variants in the filamin A (FLNA) gene. FLNA-PVNH is a heterogeneous disorder, and the phenotype is associated with neurological and non-neurological features including cardiovascular, gastrointestinal, pulmonary, haematological, cutaneous and skeletal manifestations. No clear definition of the FLNA-PVNH phenotype has been established, but the patients are predominantly females with seizures, cardiovascular manifestations, and normal intelligence or mild intellectual disability. Herein, we describe a PVNH patient diagnosed with a novel heterozygous missense variant in FLNA after an atypical presentation of deep vein thrombosis and thrombocytopenia. Clinical evaluation found hypermobility, cardiovascular and skin manifestations. Moreover, we conducted a literature review of 186 FLNA-PVNH patients to describe the phenotypic spectrum. In conclusion, our patient highlights the importance of thorough clinical evaluation to identify manifestations in this very heterogeneous disorder. The phenotypic review may guide clinicians in the assessment and follow-up of FLNA-PVNH patients.

[Prenatal ultrasound prognostic of myelomeningocele at the era of fetal surgery]

Myelomeningocele (MMC) is a severe congenital condition responsible for motor and sensory impairments of the lower limbs, incontinence and cognitive impairment. Its screening, sometimes as early as the first trimester, is one of the major goals of modern prenatal care, supported by the emergence of prenatal surgery that results in a significant improvement in motor function, ambulation and ventriculoperitoneal shunt rate in patients undergoing in-utero surgery. From screening to pre- and post-operative prognostic evaluation, prenatal ultrasound is now an essential tool in the antenatal management of this condition. Using the multi planar and three-dimensional modes, it can be used to assess the vertebral level of MMC, which remains the key antenatal prognostic marker for motor function and ambulation, incontinence and the need for a ventriculo-peritoneal shunt. A careful and systematic ultrasound examination also makes it possible to assess the severity and progression of ventriculomegaly, to search for associated cerebral, spinal cord or vertebral anomalies, or to rule out exclusion criteria for in-utero surgery such as severe kyphosis or serious cortical anomalies. New tools from post-natal evaluation, such as the "metameric" ultrasound assessment of lower limb mobility, appear to be promising either for the initial examination or after in-utero surgery. Ultrasonography, associated with fetal MRI, cytogenetic and next generation sequencing, now allows a highly customized prognostic evaluation of these fetuses affected by MMC and provides the parents with the best possible information on the expected benefits and limitations of fetal surgery.

New insights in cerebral findings associated with fetal myelomeningocele: a retrospective cohort study in a single tertiary centre

OBJECTIVE

To investigate cerebral anomalies other than Chiari type 2 malformation in fetuses with myelomeningocele (MMC).

DESIGN

A retrospective cohort study in a single tertiary centre.

SETTING

A review of associated cerebral anomalies in cases with prenatal diagnosis of myelomeningocele.

POPULATION

Seventy cases of fetal myelomeningocele.

METHODS

Ultrasound and MRI images were blindly reviewed. Postnatal imaging and results of the postmortem results were also reviewed. The association between cerebral anomalies and the following ultrasound findings was measured: level of the defect, ventriculomegaly, microcephaly and fetal talipes.

MAIN OUTCOME MEASURES

A microcephaly was observed in 32/70 cases (46%) and a ventriculomegaly was observed in 39/70 cases (56%). Other cerebral anomalies were diagnosed in 47/70 (67%).

RESULTS

Other cerebral anomalies were represented by 42/70 cases with abnormal CC (60%), 8/70 cases with perinodular heterotopia (PNH; 11%), 2/70 cases with abnormal gyration (3%). MRI performed only in fetal surgery cases confirmed the ulltrasound findings in all cases and provided additional findings in two cases (PNH). Risk ratios of fetal cerebral anomalies associated with MMC did not reach significance for microcephaly, ventriculomegaly, talipes or the level of the defect There was an overall good correlation between pre- and postnatal findings with a Kappa value of 0.79 [95% CI 0.57-1] and 82% agreement.

CONCLUSION

Fetal brain anomalies other than Chiari type 2 malformation are frequently observed in fetuses with myelomeningocele, predominantly represented by CC anomalies. Whether these associated cerebral anomalies have an impact on selecting cases eligible for fetal surgery needs further evaluation.

TWEETABLE ABSTRACT

Fetal cerebral anomalies other than Chiari type 2 malformation, microcephaly, and ventriculomegaly may be associated with MMC in up to 67% of the cases.

Prenatally diagnosed developmental abnormalities of the central nervous system and genetic syndromes: A practical review

Developmental brain abnormalities are complex and can be difficult to diagnose by prenatal imaging because of the ongoing growth and development of the brain throughout pregnancy and the limitations of ultrasound, often requiring fetal magnetic resonance imaging as an additional tool. As for all major structural congenital anomalies, amniocentesis with chromosomal microarray and a karyotype is the first-line recommended test for the genetic work-up of prenatally diagnosed central nervous system (CNS) abnormalities. Many CNS defects, especially neuronal migration defects affecting the cerebral and cerebellar cortex, are caused by single-gene mutations in a large number of different genes. Early data suggest that prenatal diagnostic exome sequencing for fetal CNS defects will have a high diagnostic yield, but interpretation of sequencing results can be complex. Yet a genetic diagnosis is important for prognosis prediction and recurrence risk counseling. The evaluation and management of such patients is best done in a multidisciplinary team approach. Here, we review general principles of the genetic work-up for fetuses with CNS defects and review categories of genetic causes of prenatally diagnosed CNS phenotypes.