Biallelic loss-of-function variants of SLC12A9 cause lysosome dysfunction and a syndromic neurodevelopmental disorder.

PURPOSE: Pathogenic variants of FIG4 generate enlarged lysosomes and neurological and developmental disorders. To identify additional genes regulating lysosomal volume, we carried out a genome-wide activation screen to detect suppression of enlarged lysosomes in FIG4-/- cells. METHODS: The CRISPR-a gene activation screen utilized sgRNAs from the promoters of protein-coding genes. Fluorescence-activated cell sorting separated cells with correction of the enlarged lysosomes from uncorrected cells. Patient variants of SLC12A9 were identified by exome or genome sequencing and studied by segregation analysis and clinical characterization. RESULTS: Overexpression of SLC12A9, a solute co-transporter, corrected lysosomal swelling in FIG4-/- cells. SLC12A9 (NP_064631.2) colocalized with LAMP2 at the lysosome membrane. Biallelic variants of SLC12A9 were identified in 3 unrelated probands with neurodevelopmental disorders. Common features included intellectual disability, skeletal and brain structural abnormalities, congenital heart defects, and hypopigmented hair. Patient 1 was homozygous for nonsense variant p.(Arg615∗), patient 2 was compound heterozygous for p.(Ser109Lysfs∗20) and a large deletion, and proband 3 was compound heterozygous for p.(Glu290Glyfs∗36) and p.(Asn552Lys). Fibroblasts from proband 1 contained enlarged lysosomes that were corrected by wild-type SLC12A9 cDNA. Patient variant p.(Asn552Lys) failed to correct the lysosomal defect. CONCLUSION: Impaired function of SLC12A9 results in enlarged lysosomes and a recessive disorder with a recognizable neurodevelopmental phenotype.

Exercise-Induced Asthma: Managing Respiratory Issues in Athletes.

Asthma is a complex respiratory condition characterized by chronic airway inflammation and variable expiratory airflow limitation, affecting millions globally. Among athletes, particularly those competing at elite levels, the prevalence of respiratory conditions is notably heightened, varying between 20% and 70% across specific sports. Exercise-induced bronchoconstriction (EIB) is a common issue among athletes, impacting their performance and well-being. The prevalence rates vary based on the sport, training environment, and genetics. Exercise is a known trigger for asthma, but paradoxically, it can also improve pulmonary function and alleviate EIB severity. However, athletes' asthma phenotypes differ, leading to varied responses to medications and challenges in management. The unique aspects in athletes include heightened airway sensitivity, allergen, pollutant exposure, and temperature variations. This review addresses EIB in athletes, focusing on pathogenesis, diagnosis, and treatment. The pathogenesis of EIB involves complex interactions between physiological and environmental factors. Airway dehydration and cooling are key mechanisms, leading to osmotic and thermal theories. Airway inflammation and hyper-responsiveness are common factors. Elite athletes often exhibit distinct inflammatory responses and heightened airway sensitivity, influenced by sport type, training, and environment. Swimming and certain sports pose higher EIB risks, with chlorine exposure in pools being a notable factor. Immune responses, lung function changes, and individual variations contribute to EIB in athletes. Diagnosing EIB in athletes requires objective testing, as baseline lung function tests can yield normal results. Both EIB with asthma (EIBA) and without asthma (EIBwA) must be considered. Exercise and indirect bronchoprovocation tests provide reliable diagnoses. In athletes, exercise tests offer effectiveness in diagnosing EIB. Spirometry and bronchodilation tests are standard approaches, but the diagnostic emphasis is shifting toward provocation tests. Despite its challenges, achieving an optimal diagnosis of EIA constitutes the cornerstone for effective management, leading to improved performance, reduced risk of complications, and enhanced quality of life. The management of EIB in athletes aligns with the general principles for symptom control, prevention, and reducing complications. Non-pharmacological approaches, including trigger avoidance and warming up, are essential. Inhaled corticosteroids (ICS) are the cornerstone of asthma therapy in athletes. Short-acting beta agonists (SABA) are discouraged as sole treatments. Leukotriene receptor antagonists (LTRA) and mast cell stabilizing agents (MCSA) are potential options. Optimal management improves the athletes' quality of life and allows them to pursue competitive sports effectively.

Neuroblastoma Patients' Outcome and Chromosomal Instability.

Chromosomal instability (CIN) induces a high rate of losses or gains of whole chromosomes or parts of chromosomes. It is a hallmark of most human cancers and one of the causes of aneuploidy and intra-tumor heterogeneity. The present study aimed to evaluate the potential prognostic role of CIN in NB patients at diagnosis. We performed array comparative genomic hybridization analyses on 451 primary NB patients at the onset of the disease. To assess global chromosomal instability with high precision, we focused on the total number of DNA breakpoints of gains or losses of chromosome arms. For each tumor, an array-CGH-based breakpoint instability index (BPI) was assigned which defined the total number of chromosomal breakpoints per genome. This approach allowed us to quantify CIN related to whole genome disruption in all NB cases analyzed. We found differences in chromosomal breakages among the NB clinical risk groups. High BPI values are negatively associated with survival of NB patients. This association remains significant when correcting for stage, age, and MYCN status in the Cox model. Stratified analysis confirms the prognostic effect of BPI index in low-risk NB patients with non-amplified MYCN and with segmental chromosome aberrations.

Vein of Galen aneurysmal malformation in newborns: a retrospective study to describe a paradigm of treatment and identify risk factors of adverse outcome in a referral center.

Background: Vein of Galen aneurysmal malformation (VGAM) is a rare cerebral vascular malformation associated with significant morbidity and mortality. Newborns with VGAM without adequate treatment may develop rapidly deteriorating high output heart failure (HOHF) and are at risk for severe neurological outcomes. Objective: To describe the clinical course and management of newborns with VGAM, and identify which echocardiographic and neuroradiologic factors may be associated with severe heart failure at birth and adverse short term outcomes. Methods: This is a single center retrospective cohort study including all consecutive newborns with VGAM admitted to Gaslini Children's Hospital between 2009 and 2022. We reviewed clinical data, intensive care support, fetal and neonatal cardiologic and neuroradiologic findings and we studied the association with severe HOHF, endovascular complications and death. Results: Out of 40 newborns, 17 (42.5%) developed severe HOHF requiring early endovascular procedures. Medical treatment was focused on the main components of HOHF by providing inotropic support and peripheral vasodilation. Pulmonary vasodilators were avoided to reduce the negative effects of pulmonary overflow and prevent vascular remodeling. Reduction of the obligatory left to right shunt through the VGAM was possible only through endovascular treatment. Fetal cardiothoracic ratio was significantly associated with severe HOHF at birth and death. Cardiologic parameters of right ventricular overload, pulmonary hypertension and systemic steal were the leading findings associated with haemodynamic compromise at birth. The mediolateral diameter of the straight or falcine sinus at its shortest section (SS-MD), and arterial pseudofeeders were significantly associated with severe HOHF at birth in prenatal and postnatal assessments. None of the postnatal echocardiographic and MRI variables, nor a higher inotropic support were associated with major periprocedural complications or death. Mortality was due to palliation for congenital severe brain damage (4/40, 10%), or major periprocedural complications (3/40, 7.5%). None of the patients died due to HOHF and multiorgan failure. Overall survival at discharge was 82.5% (33/40). Conclusions: The complexity of neonatal VGAM pathophysiology requires a multidisciplinary approach, specialized intensive care management, and early endovascular treatment to reduce mortality and optimize clinical outcomes. Cardiologic and neuroradiologic parameters are key to define risk stratification and treatment strategies.

Elucidating the clinical and molecular spectrum of SMARCC2-associated NDD in a cohort of 65 affected individuals.

PURPOSE: Coffin-Siris and Nicolaides-Baraitser syndromes are recognizable neurodevelopmental disorders caused by germline variants in BAF complex subunits. The SMARCC2 BAFopathy was recently reported. Herein, we present clinical and molecular data on a large cohort. METHODS: Clinical symptoms for 41 novel and 24 previously published affected individuals were analyzed using the Human Phenotype Ontology. For genotype-phenotype correlations, molecular data were standardized and grouped into non-truncating and likely gene-disrupting (LGD) variants. Missense variant protein expression and BAF-subunit interactions were examined using 3D protein modeling, co-immunoprecipitation, and proximity-ligation assays. RESULTS: Neurodevelopmental delay with intellectual disability, muscular hypotonia, and behavioral disorders were the major manifestations. Clinical hallmarks of BAFopathies were rare. Clinical presentation differed significantly, with LGD variants being predominantly inherited and associated with mildly reduced or normal cognitive development, whereas non-truncating variants were mostly de novo and presented with severe developmental delay. These distinct manifestations and non-truncating variant clustering in functional domains suggest different pathomechanisms. In vitro testing showed decreased protein expression for N-terminal missense variants similar to LGD. CONCLUSION: This study improved SMARCC2 variant classification and identified discernible SMARCC2-associated phenotypes for LGD and non-truncating variants, which were distinct from other BAFopathies. The pathomechanism of most non-truncating variants has yet to be investigated.

Multiple Genes with Potential Tumor Suppressive Activity Are Present on Chromosome 10q Loss in Neuroblastoma and Are Associated with Poor Prognosis.

Neuroblastoma (NB) is a tumor affecting the peripheral sympathetic nervous system that substantially contributes to childhood cancer mortality. Despite recent advances in understanding the complexity of NB, the mechanisms determining its progression are still largely unknown. Some recurrent segmental chromosome aberrations (SCA) have been associated with poor survival. However, the prognostic role of most SCA has not yet been investigated. We examined a cohort of 260 NB primary tumors at disease onset for the loss of chromosome 10q, by array-comparative genomic hybridization (a-CGH) and Single Nucleotide Polymorphism (SNP) array and we found that 26 showed 10q loss, while the others 234 displayed different SCA. We observed a lower event-free survival for NB patients displaying 10q loss compared to patients with tumors carrying other SCA. Furthermore, analyzing the region of 10q loss, we identified a cluster of 75 deleted genes associated with poorer outcome. Low expression of six of these genes, above all CCSER2, was significantly correlated to worse survival using in silico data from 786 NB patients. These potential tumor suppressor genes can be partly responsible for the poor prognosis of NB patients with 10q loss.

Case report: Revascularization failure in NF1-related moyamoya syndrome after selumetinib: A possible pathophysiological correlation?

Neurofibromatosis type 1 (NF1) is a neurocutaneous syndrome caused by pathogenic variants in the NF1 gene, encoding a multidomain inhibitor of Ras activity. Thus, NF1 is considered a RASopathy and drugs targeting the RAS/mitogen-activated protein kinase (MAPK) pathway, such as the MAP kinase (MEK) 1/2 inhibitor Selumetinib, are promising therapeutic options to treat NF1-associated tumors, especially plexiform neurofibromas and optic way gliomas. However, surgical treatment is often required for NF1-related cerebrovascular manifestations, such as moyamoya syndrome (MMS). We report a case of an 8-year-old patient receiving Selumetinib at the dose of 25 mg/m2 orally 2 times a day as a treatment for many plexiform neurofibromas. He suffered from two close strokes and brain MRI revealed a severe cerebral vasculopathy consistent with MMS, with marked stenosis of both the internal carotid arteries. A two-step surgical revascularization procedure was performed, consisting of a direct by-pass with an encephalo-mio-synangiosis (EMS) followed by encephalo-duro-arterio-synangiosis (EDAS). Surprisingly, despite the surgical technical success, follow-up MRI revealed lack of the expected revascularization. Selumetinib is a powerful therapeutic option in the treatment of severe NF1-related tumors. However, our findings suggest that this drug may interfere with cerebral neovascularization in patients with MMS requiring surgical revascularization. This is supported by the crucial role of the Vascular-Endothelial Growth Factor (VEGF), whose signaling pathway involve MAPK, as promoter of the neovascularization. Our observations suggest to adopt an imaging surveillance strategy to prevent unfavorable surgical outcome in patients with NF1-associated MMS receiving Selumetinib, and that priority should be given to surgical revascularization.

Moyamoya Vasculopathy in Neurofibromatosis Type 1 Pediatric Patients: The Role of Rare Variants of RNF213.

Neurofibromatosis type 1 (NF1) is a neurocutaneous disorder caused by mutations in NF1 gene, coding for neurofibromin 1. NF1 can be associated with Moyamoya disease (MMD), and this association, typical of paediatric patients, is referred to as Moyamoya syndrome (MMS). MMD is a cerebral arteriopathy characterized by the occlusion of intracranial arteries and collateral vessel formation, which increase the risk of ischemic and hemorrhagic events. RNF213 gene mutations have been associated with MMD, so we investigated whether rare variants of RNF213 could act as genetic modifiers of MMS phenotype in a pediatric cohort of 20 MMS children, 25 children affected by isolated MMD and 47 affected only by isolated NF1. By next-generation re-sequencing (NGS) of patients' DNA and gene burden tests, we found that RNF213 seems to play a role only for MMD occurrence, while it does not appear to be involved in the increased risk of Moyamoya for MMS patients. We postulated that the loss of neurofibromin 1 can be enough for the excessive proliferation of vascular smooth muscle cells, causing Moyamoya arteriopathy associated with NF1. Further studies will be crucial to support these findings and to elucidate the possible role of other genes, enhancing our knowledge about pathogenesis and treatment of MMS.

Natural history of familial cerebral cavernous malformation syndrome in children: a multicenter cohort study.

PURPOSE: There is limited data concerning neuroimaging findings and longitudinal evaluation of familial cerebral cavernous malformations (FCCM) in children. Our aim was to study the natural history of pediatric FCCM, with an emphasis on symptomatic hemorrhagic events and associated clinical and imaging risk factors. METHODS: We retrospectively reviewed all children diagnosed with FCCM in four tertiary pediatric hospitals between January 2010 and March 2022. Subjects with first available brain MRI and [Formula: see text] 3 months of clinical follow-up were included. Neuroimaging studies were reviewed, and clinical data collected. Annual symptomatic hemorrhage risk rates and cumulative risks were calculated using survival analysis and predictors of symptomatic hemorrhagic identified using regression analysis. RESULTS: Forty-one children (53.7% males) were included, of whom 15 (36.3%) presenting with symptomatic hemorrhage. Seven symptomatic hemorrhages occurred during 140.5 person-years of follow-up, yielding a 5-year annual hemorrhage rate of 5.0% per person-year. The 1-, 2-, and 5-year cumulative risks of symptomatic hemorrhage were 7.3%, 14.6%, and 17.1%, respectively. The latter was higher in children with prior symptomatic hemorrhage (33.3%), CCM2 genotype (33.3%), and positive family history (20.7%). Number of brainstem (adjusted hazard ratio [HR] = 1.37, P = 0.005) and posterior fossa (adjusted HR = 1.64, P = 0.004) CCM at first brain MRI were significant independent predictors of prospective symptomatic hemorrhage. CONCLUSION: The 5-year annual and cumulative symptomatic hemorrhagic risk in our pediatric FCCM cohort equals the overall risk described in children and adults with all types of CCM. Imaging features at first brain MRI may help to predict potential symptomatic hemorrhage at 5-year follow-up.

Abdominal rhabdoid tumor presenting with symptomatic spinal epidural compression in a newborn. A case report.

The occurrence of an abdominal tumor invading the spinal canal and causing symptoms of epidural compression is rare in an infant, and exceptional at birth. Peripheral neuroblastic tumors are by far the most common cause. Emergency chemotherapy is commonly curative, though permanent sequelae are possible. Although other malignancies may be involved, no case of rhabdoid tumors at birth has been reported. We describe the case of a neonate who presented symptoms of spinal epidural compression at birth secondary to a rhabdoid tumor. As expected with this highly malignant tumor, the patient experienced a rapidly progressive clinical course and died within three months of diagnosis.

Early molecular diagnosis of BRAF status drives the neurosurgical management in BRAF V600E-mutant pediatric low-grade gliomas: a case report.

BACKGROUND: To date, this is the only report showing with close and consecutive magnetic resonance images the extremely rapid response of two types of pediatric low-grade gliomas (PLGG) to vemurafenib and its impact on the surgical approach. CASES PRESENTATION: We report two cases of symptomatic PLGG treated with vemurafenib, a BRAF inhibitor: in a 12-year-old girl it was used as first-line medical treatment, reducing the tumor by 45% within a month and stabilizing to 76% after a year; in a 3-year-old boy with no improvement after SIOP LGG 2004 Protocol, vemurafenib induced in only one week a 34% shrinkage and solved the hydrocephalus, avoiding surgical operation. DISCUSSION AND CONCLUSIONS: Our cases demonstrate how an early molecular diagnosis of BRAF mutations through the neurosurgical biopsy is essential to promptly start targeted therapies., whose effect can influence both therapeutic and surgical decisions, hopefully reducing the occurrence of second neurosurgery with associated risks of neurological sequelae.

Clinical and genetic analysis of patients with segmental overgrowth features and somatic mammalian target of rapamycin (mTOR) pathway disruption: Possible novel clinical issues.

Segmental overgrowth syndromes include a group of clinical entities, all characterized by the abundant proliferation of tissues or organs in association with vascular abnormalities. These syndromes show a wide spectrum of severity ranging from limited involvement of only small areas of the body to complex cases with impressive distortions of multiple tissues and organs. It is now clear that somatic mutations in genes of the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway (in brief "mTOR pathway") are responsible for such entities. Not all the cells of the body carry the same causative mutation, which is mosaic, appearing from two (or more) distinct cell lineages after fertilization. In this article, we reconsider the clinical spectrum and surveillance programs of patients with segmental overgrowth syndromes, based on the features of six patients with diverse clinical forms of overgrowth and pathogenic variants in genes of the mTOR pathway.

Effects of SARS-CoV-2 Infection on Pulmonary Function Tests and Exercise Tolerance.

Introduction: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been shown to cause long-term pulmonary sequelae. Objects: The aim of this study was to evaluate the consequences of the SARS-CoV-2 infection on pulmonary function and on the 6-min walk test related to the severity of the disease. Methods: A cross-sectional study was conducted at the "Policlinico Tor Vergata" Academic Hospital (Rome, Italy), including 75 patients evaluated in post-COVID clinics at the Respiratory Units between November 2020 and September 2021. Complete pulmonary function tests, 6-min walk tests and persistence of symptoms were performed. Results: Of the 75 subjects, 23 had mild, 16 moderate, 26 severe and 10 very severe COVID-19, classified according to WHO. Very severe patients had a lower FVC (100 ± 10%pr) compared to the other groups (116 ± 16%pr, 116 ± 13%pr, 122 ± 20%pr from mild to severe; p < 0.05) and a lower TLC (94 ± 13%pr) compared to the others (102 ± 10%pr, 108 ± 15%pr, 108 ± 12%pr from mild to severe; p < 0.05). DLco and DLco/VA were similar among groups. At the 6MWT, distance, rest and nadir SpO2 were similar among groups, but all groups presented a significant decrease in SpO2 from rest to nadir (Rest SpO2: 97.0 ± 1.0% vs. Nadir SpO2: 93.6 ± 2.7%, p < 0.01). A positive correlation was found between desaturation and delta SpO2 (rest­nadir) (R: 0.29, p < 0.05) and the Distance Desaturation Product (R: 0.39, p < 0.01). Conclusions: These results showed that, although the PFTs are within the normal range, there is still a mild restrictive spirometric pattern after six months in very severe subjects. Moreover, the only persistent pathological sequalae of SARS-CoV-2 infection were a mild desaturation at 6MWT, despite the severity of the infection.

A homozygous MED11 C-terminal variant causes a lethal neurodegenerative disease.

PURPOSE: The mediator (MED) multisubunit-complex modulates the activity of the transcriptional machinery, and genetic defects in different MED subunits (17, 20, 27) have been implicated in neurologic diseases. In this study, we identified a recurrent homozygous variant in MED11 (c.325C>T; p.Arg109Ter) in 7 affected individuals from 5 unrelated families. METHODS: To investigate the genetic cause of the disease, exome or genome sequencing were performed in 5 unrelated families identified via different research networks and Matchmaker Exchange. Deep clinical and brain imaging evaluations were performed by clinical pediatric neurologists and neuroradiologists. The functional effect of the candidate variant on both MED11 RNA and protein was assessed using reverse transcriptase polymerase chain reaction and western blotting using fibroblast cell lines derived from 1 affected individual and controls and through computational approaches. Knockouts in zebrafish were generated using clustered regularly interspaced short palindromic repeats/Cas9. RESULTS: The disease was characterized by microcephaly, profound neurodevelopmental impairment, exaggerated startle response, myoclonic seizures, progressive widespread neurodegeneration, and premature death. Functional studies on patient-derived fibroblasts did not show a loss of protein function but rather disruption of the C-terminal of MED11, likely impairing binding to other MED subunits. A zebrafish knockout model recapitulates key clinical phenotypes. CONCLUSION: Loss of the C-terminal of MED subunit 11 may affect its binding efficiency to other MED subunits, thus implicating the MED-complex stability in brain development and neurodegeneration.

Dyslipidemia in Children Treated with a BRAF Inhibitor for Low-Grade Gliomas: A New Side Effect?

BRAF inhibitors, in recent years, have played a central role in the disease control of unresectable BRAF-mutated pediatric low-grade gliomas (LGGs). The aim of the study was to investigate the acute and long-term effects of vemurafenib on the lipid metabolism in children treated for an LGG. In our cohort, children treated with vemurafenib (n = 6) exhibited alterations in lipid metabolism a few weeks after starting, as was demonstrated after 1 month (n = 4) by the high plasma levels of the total cholesterol (TC = 221.5 ± 42.1 mg/dL), triglycerides (TG = 107.8 ± 44.4 mg/dL), and low-density lipoprotein (LDL = 139.5 ± 51.5 mg/dL). Despite dietary recommendations, the dyslipidemia persisted over time. The mean lipid levels of the TC (222.3 ± 34.7 mg/dL), TG (134.8 ± 83.6 mg/dL), and LDL (139.8 ± 46.9 mg/dL) were confirmed abnormal at the last follow-up (45 ± 27 months, n = 6). Vemurafenib could be associated with an increased risk of dyslipidemia. An accurate screening strategy in new clinical trials, and a multidisciplinary team, are required for the optimal management of unexpected adverse events, including dyslipidemia.

Genomic Analysis Made It Possible to Identify Gene-Driver Alterations Covering the Time Window between Diagnosis of Neuroblastoma 4S and the Progression to Stage 4.

Neuroblastoma (NB) is a tumor of the developing sympathetic nervous system. Despite recent advances in understanding the complexity of NB, the mechanisms that determine its regression or progression are still largely unknown. Stage 4S NB is characterized by a favorable course of disease and often by spontaneous regression, while progression to true stage 4 is a very rare event. Here, we focused on genomic analysis of an NB case that progressed from stage 4S to stage 4 with a very poor outcome. Array-comparative genomic hybridization (a-CGH) on tumor-tissue DNA, and whole-exome sequencing (WES) on exosomes DNA derived from plasma collected at the onset and at the tumor progression, pointed out relevant genetic changes that can explain this clinical worsening. The combination of a-CGH and WES data allowed for the identification iof somatic copy number aberrations and single-nucleotide variants in genes known to be responsible for aggressive NB. KLRB1, MAPK3 and FANCA genes, which were lost at the time of progression, were studied for their possible role in this event by analyzing in silico the impact of their expression on the outcome of 786 NB patients.

Spinal involvement in pediatric familial cavernous malformation syndrome.

PURPOSE: The aim of the study was to assess the prevalence and characteristics of spinal cord cavernous malformations (SCCM) and intraosseous spinal vascular malformations (ISVM) in a pediatric familial cerebral cavernous malformation (FCCM) cohort and evaluate clinico-radiological differences between children with (SCCM +) and without (SCCM-) SCCM. METHODS: All patients with a pediatric diagnosis of FCCM evaluated at three tertiary pediatric hospitals between January 2010 and August 2021 with [Formula: see text] 1 whole spine MR available were included. Brain and spine MR studies were retrospectively evaluated, and clinical and genetic data collected. Comparisons between SCCM + and SCCM- groups were performed using student-t/Mann-Whitney or Fisher exact tests, as appropriate. RESULTS: Thirty-one children (55% boys) were included. Baseline spine MR was performed (mean age = 9.7 years) following clinical manifestations in one subject (3%) and as a screening strategy in the remainder. Six SCCM were detected in five patients (16%), in the cervico-medullary junction (n = 1), cervical (n = 3), and high thoracic (n = 2) regions, with one appearing during follow-up. A tendency towards an older age at first spine MR (P = 0.14) and [Formula: see text] 1 posterior fossa lesion (P = 0.13) was observed in SCCM + patients, lacking statistical significance. No subject demonstrated ISVM. CONCLUSION: Although rarely symptomatic, SCCM can be detected in up to 16% of pediatric FCCM patients using diverse spine MR protocols and may appear de novo. ISVM were instead absent in our cohort. Given the relative commonality of asymptomatic SCCM, serial screening spine MR should be considered in FCCM starting in childhood.

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.

The first case of mosaic MNX1 mutation in an adult female with features of Currarino syndrome.

BACKGROUND: Currarino syndrome (CS) is a rare genetic condition characterized by the association of three major clinical signs: anorectal malformation (ARM), sacro-coccygeal bone defects, and presacral mass. Different kinds of ARM can be present such as anteriorly placed anus, imperforate anus, anorectal stenosis, rectal duplication, and fistulae. The presacral mass can be a benign teratoma, a dermoid or neurenteric cyst, anterior meningocele or hamartoma. Females are more frequently affected and usually present with associated gynecologic and urinary tract problems. CS is considered an autosomal dominant trait, with reduced penetrance and variable expressivity. CS is associated with mutations in the MNX1 gene (motor neuron and pancreas homeobox-1, previously known as HLXB9) mapped to chromosome 7q36. Heterozygous loss-of-function mutations in the coding sequence of MNX1 gene have been reported in nearly all familial CS cases and in approximately 30% of CS sporadic patients. CASE: Here, we present the case of a woman with features of CS carrying a mosaic mutation in the coding region of MNX1 gene. This is the only reported case of a CS diagnosis in which the mutation is present in less than 50% of cells. CONCLUSION: The lower detection rate of MNX1 mutations in sporadic cases could similarly be explained by somatic mosaicism, mutations occurring outside the coding regions, or genetic heterogeneity.