Three Generations of FLNA-Associated Periventricular Nodular Heterotopia

We present a family with 3 generations of FLNA gene-associated periventricular nodular heterotopia (PVNH), with a unique presentation in a fetus with multiple neurologic malformations. Neurologic abnormalities were noted on routine fetal imaging for a 33-year-old G1P0 woman; absence of the corpus callosum and PVNH was confirmed on follow-up MRI. This prompted genetic evaluation, revealing a nonsense mutation in the FLNA gene. Familial genetic analysis and neuroimaging revealed the same variant and MRI evidence of PVNH in the fetus’s asymptomatic mother, and maternal grandmother, who had a long history of seizure disorder. Such phenotypic variability within a single family demonstrates the spectrum of PVNH and the importance of genetic counseling for patients with PVNH. This case also adds to existing literature on the rare but not unique presentation of FLNA-associated fetal malformations.

Bipolar disorder with Melnick–Needles syndrome and periventricular nodular heterotopia: two case reports and a review of the literature

Background Melnick–Needles syndrome and periventricular nodular heterotopia are two usually mutually exclusive phenotypes of F-actin-binding cytoskeletal phosphoprotein Filamin-A mutations. Melnick–Needles syndrome is a rare X-linked condition that is lethal in males and shows great phenotypic variability in affected females. It is caused by mutations in Filamin-A gene, which encodes the protein Filamin A. Defects of the human Filamin-A gene also cause X-linked periventricular nodular heterotopia, a malformation of neuronal migration characterized by nodules of neurons in inappropriate location adjacent to the walls of the lateral ventricles. Case presentation We report on two Caucasian adolescent females, sisters, diagnosed with Melnick–Needles syndrome and bilateral periventricular nodular heterotopia, who developed bipolar disorder and somatic symptoms disorder at a young age. We also present a review of the literature about mental disorders associated with periventricular nodular heterotopia. Our report shows that patients presenting with atypical and heterogeneous psychiatric disease may have an underrecognized anatomical brain abnormality on genetic basis. Conclusions We found records of psychiatric disorders associated with periventricular nodular heterotopia; nevertheless, this is the first report of bipolar disorder occurring in individuals with periventricular nodular heterotopia, and the first report of any psychiatric disorder in individuals affected by Melnick–Needles syndrome. In conclusion, this case report may contribute to characterizing the phenotype of this very rare syndrome.

“Within a minute” detection of focal cortical dysplasia

Purpose To evaluate a MRI postprocessing tool for the enhanced and rapid detection of focal cortical dysplasia (FCD). Methods MP2RAGE sequences of 40 consecutive, so far MRI-negative patients and of 32 healthy controls were morphometrically analyzed to highlight typical FCD features. The resulting morphometric maps served as input for an artificial neural network generating a FCD probability map. The FCD probability map was inversely normalized, co-registered to the MPRAGE2 sequence, and re-transferred into the PACS system. Co-registered images were scrolled through “within a minute” to determine whether a FCD was present or not. Results Fifteen FCD, three subcortical band heterotopias (SBH), and one periventricular nodular heterotopia were identified. Of those, four FCD and one SBH were only detected by MRI postprocessing while one FCD and one focal polymicrogryia were missed, respectively. False-positive results occurred in 21 patients and 22 healthy controls. However, true positive cluster volumes were significantly larger than volumes of false-positive clusters (p < 0.001). The area under the curve of the receiver operating curve was 0.851 with a cut-off volume of 0.05 ml best indicating a FCD. Conclusion Automated MRI postprocessing and presentation of co-registered output maps in the PACS allowed for rapid (i.e., “within a minute”) identification of FCDs in our clinical setting. The presence of false-positive findings currently requires a careful comparison of postprocessing results with conventional MR images but may be reduced in the future using a neural network better adapted to MP2RAGE images.

Magnetic resonance–guided laser interstitial thermal therapy for pediatric periventricular nodular heterotopia-related epilepsy

OBJECTIVE Periventricular nodular heterotopia (PVNH) is a result of disrupted neuronal migration from the ventricular system and can be a rare cause of refractory focal epilepsy. The goal of this case series was to describe the treatment of pediatric PVNH-related epilepsy with MR-guided laser interstitial thermal ablation. METHODS Patients treated at a single institution with MR-guided laser interstitial thermal therapy (MRgLITT) for PVNH-related epilepsy were identified. Preoperative and postoperative seizure outcomes and procedural information were evaluated. RESULTS Five children with PVNH treated with MRgLITT were reviewed; 1 child was treated twice. Three patients were female; the median age was 10.9 years. Five of 6 treatments were preceded by stereoelectroencephalography phase II monitoring. Three children experienced unilateral PVNH, and 2 had bilateral seizures. The median number of seizures recorded during phase II monitoring was 2; the median number of ablation targets was 2 (range 1–4). All patients experienced a decrease in seizure frequency; 4 patients (80%) had an Engel class ≤ III at the last follow-up (range I–IV). One child experienced right hemianopia posttreatment. CONCLUSIONS This case series investigation has illustrated a novel, minimally invasive approach for treating pediatric PVNH-related epilepsy. Further study of this technique with comparison with other surgical techniques is warranted.

ARF1 haploinsufficiency causes periventricular nodular heterotopia with variable clinical expressivity

The primary anatomical defect leading to periventricular nodular heterotopia occurs within the neural progenitors along the neuroepithelial lining of the lateral ventricles and results from a defect in the initiation of neuronal migration, following disruption of the neuroependyma and impaired neuronal motility. Growing evidence indicates that the FLNA-dependent actin dynamics and regulation of vesicle formation and trafficking by activation of ADP-ribosylation factors (ARFs) can play an important role in this cortical malformation. We report the first inherited variant of ARF1 in a girl with intellectual disability and periventricular nodular heterotopia who inherited the variant from the father with previously undiagnosed single nodular heterotopia and mild clinical expression. Additionally, both patients presented some features suggestive of hypohidrotic ectodermal dysplasia. These clinical features showed similarities to those of three previously reported cases with ARF1 missense variants, confirming that haploinsufficiency of this gene causes a recognisable neurological disorder with abnormal neuronal migration and variable clinical expressivity.

Periventricular nodular heterotopias an atypical manifestation of Joubert syndrome

Joubert syndrome (JS) is characterized by varying degrees of mid and hindbrain malformations. A thickened superior cerebellar peduncle (“molar tooth sign”), varying degree of cerebellar vermian clefting, and an oddly shaped (“bat-wing”) fourth ventricle are essential diagnostic cues on imaging. When JS is associated with renal, ocular, hepatobiliary, or oro-facial abnormalities, the term Joubert syndrome and related disorders (JSRD) is used. We report a classic case of this rare disease in a 5 month old male child who presented to our department for assessment of developmental delay. MRI revealed molar-tooth appearance of midbrain, an abnormally shaped fourth ventricle, and vermian aplasia. Additional findings present in our case were corpus callosum dysgenesis, colpocephaly, generalized cortical atrophy, and periventricular nodular heterotopia. Subsequently, an ultrasound of the abdomen was performed to look for any associated anomalies. It revealed diffuse bilateral echogenic kidneys with attenuated corticomedullary differentiation (likely due to micro cysts in medulla) and few thin-walled peripheral renal cortical cysts. Callosal dysgenesis, colpocephaly, cortical atrophy and cortical heterotopias are less common manifestations of JS/JSRD and periventricular nodular heterotopia has been infrequently reported in cases of Joubert syndrome. Key-words: Joubert Syndrome, MRI, Molar Tooth Sign, Periventricular Nodular Heterotopia, Bilateral Echogenic Kidneys