Olfactory bulb anomalies in KBG syndrome mouse model and patients.

ANKRD11 (ankyrin repeat domain 11) is a chromatin regulator and the only gene associated with KBG syndrome, a rare neurodevelopmental disorder. We have previously shown that Ankrd11 regulates murine embryonic cortical neurogenesis. Here, we show a novel olfactory bulb phenotype in a KBG syndrome mouse model and two diagnosed patients. Conditional knockout of Ankrd11 in murine embryonic neural stem cells leads to aberrant postnatal olfactory bulb development and reduced size due to reduction of the olfactory bulb granule cell layer. We further show that the rostral migratory stream has incomplete migration of neuroblasts, reduced cell proliferation as well as aberrant differentiation of neurons. This leads to reduced neuroblasts and neurons in the olfactory bulb granule cell layer. In vitro, Ankrd11-deficient neural stem cells from the postnatal subventricular zone display reduced migration, proliferation, and neurogenesis. Finally, we describe two clinically and molecularly confirmed KBG syndrome patients with anosmia and olfactory bulb and groove hypo-dysgenesis/agenesis. Our report provides evidence that Ankrd11 is a novel regulator of olfactory bulb development and neuroblast migration. Moreover, our study highlights a novel clinical sign of KBG syndrome linked to ANKRD11 perturbations in mice and humans.

Enhancing fetal alcohol spectrum disorders diagnosis with a classifier based on the intracerebellar gradient of volumetric undersizing.

In fetal alcohol spectrum disorders (FASD), brain growth deficiency is a hallmark of subjects both with fetal alcohol syndrome (FAS) and with non-syndromic FASD (NS-FASD, i.e., those without specific diagnostic features). However, although the cerebellum was suggested to be more severely undersized than the rest of the brain, it has not yet been given a specific place in the FASD diagnostic criteria where neuroanatomical features still count for little if anything in diagnostic specificity. We applied a combination of cerebellar segmentation tools on a 1.5 T 3DT1 brain MRI dataset from a monocentric population of 89 FASD (52 FAS, 37 NS-FASD) and 126 typically developing controls (6-20 years old), providing 8 volumes: cerebellum, vermis and 3 lobes (anterior, posterior, inferior), plus total brain volume. After adjustment of confounders, the allometric scaling relationship between these cerebellar volumes (Vi ) and the total brain or cerebellum volume (Vt ) was fitted (Vi = bVt a ), and the effect of group (FAS, control) on allometric scaling was evaluated. We then estimated for each cerebellar volume in the FAS population the deviation from the typical scaling (v DTS) learned in the controls. Lastly, we trained and tested two classifiers to discriminate FAS from controls, one based on the total cerebellum v DTS only, the other based on all the cerebellar v DTS, comparing their performance both in the FAS and the NS-FASD group. Allometric scaling was significantly different between FAS and control group for all the cerebellar volumes (p < .001). We confirmed the excess of total cerebellum volume deficit (v DTS = -10.6%) and revealed an antero-inferior-posterior gradient of volumetric undersizing in the hemispheres (-12.4%, 1.1%, 2.0%, respectively) and the vermis (-16.7%, -9.2%, -8.6%, repectively). The classifier based on the intracerebellar gradient of v DTS performed more efficiently than the one based on total cerebellum v DTS only (AUC = 92% vs. 82%, p = .001). Setting a high probability threshold for >95% specificity of the classifiers, the gradient-based classifier identified 35% of the NS-FASD to have a FAS cerebellar phenotype, compared to 11% with the cerebellum-only classifier (pFISHER = 0.027). In a large series of FASD, this study details the volumetric undersizing within the cerebellum at the lobar and vermian level using allometric scaling, revealing an anterior-inferior-posterior gradient of vulnerability to prenatal alcohol exposure. It also strongly suggests that this intracerebellar gradient of volumetric undersizing may be a reliable neuroanatomical signature of FAS that could be used to improve the specificity of the diagnosis of NS-FASD.

Combining neuroanatomical features to support diagnosis of fetal alcohol spectrum disorders.

AIM: To identify easily accessible neuroanatomical abnormalities useful for diagnosing fetal alcohol spectrum disorders (FASD) in fetal alcohol syndrome (FAS) but more importantly for the probabilistic diagnosis of non-syndromic forms (NS-FASD). METHOD: We retrospectively collected monocentric data from 52 individuals with FAS, 37 with NS-FASD, and 94 paired typically developing individuals (6-20 years, 99 males, 84 females). On brain T1-weighted magnetic resonance imaging, we measured brain size, corpus callosum length and thicknesses, vermis height, then evaluated vermis foliation (Likert scale). For each parameter, we established variations with age and brain size in comparison individuals (growth and scaling charts), then identified participants with abnormal measurements (<10th centile). RESULTS: According to growth charts, there was an excess of FAS with abnormally small brain, isthmus, splenium, and vermis. According to scaling charts, this excess remained only for isthmus thickness and vermis height. The vermis foliation was pathological in 18% of those with FASD but in no comparison individual. Overall, 39% of those with FAS, 27% with NS-FASD, but only 2% of comparison individuals presented with two FAS-recurrent abnormalities, and 19% of those with FAS had all three. Considering the number of anomalies, there was a higher likelihood of a causal link with alcohol in 14% of those with NS-FASD. INTERPRETATION: Our results suggest that adding an explicit composite neuroanatomical-radiological criterion for FASD diagnosis may improve its specificity, especially in NS-FASD. WHAT THIS PAPER ADDS: Neuroanatomical anomalies independent of microcephaly can be measured with clinical-imaging tools. Small-for-age brain, small-for-brain-size callosal isthmus or vermian height, and disrupted vermis foliation are fetal alcohol syndrome (FAS)-recurrent anomalies. Associations of these anomalies are frequent in fetal alcohol spectrum disorder (FASD) even without FAS, while exceptional in typically developing individuals. These associations support higher likelihood of causal link with alcohol in some individuals with non-syndromic FASD. A new explicit and composite neuroanatomical-radiological criterion can improve the specificity of FASD diagnosis.

Neurological outcome in WDR62 primary microcephaly.

AIM: To characterize the cortical structure, developmental, and cognitive profiles of patients with WD repeat domain 62 (WDR62)-related primary microcephaly. METHOD: In this observational study, we describe the developmental, neurological, cognitive, and brain imaging characteristics of 17 patients (six males, 11 females; mean age 12y 3mo standard deviation [SD] 5y 8mo, range 5y-24y 6mo) and identify 14 new variants of WDR62. We similarly analyse the phenotypes and genotypes of the 59 previously reported families. RESULTS: Brain malformations, including pachygyria, neuronal heterotopia, schizencephaly, and microlissencephaly, were present in 11 out of 15 patients. The mean full-scale IQ of the 11 assessed patients was 51.8 (standard deviation [SD] 12.6, range 40-70). Intellectual disability was severe in four patients, moderate in four, and mild in three. Scores on the Vineland Adaptive Behavior Scales obtained from 10 patients were low for communication and motor skills (mean 38.29, SD 7.74, and 37.71, SD 5.74 respectively). The socialization score was higher (mean 47.14, SD 12.39). We found a significant difference between scores for communication and daily living skills (mean 54.43, SD 11.6; p=0.001, one-way analysis of variance). One patient displayed progressive ataxia. INTERPRETATION: WDR62-related cognitive consequences may be less severe than expected because 3 out of 11 of the assessed patients had only mild intellectual disability and relatively preserved abilities of autonomy in daily life. We identified progressive ataxia in the second decade of life in one patient, which should encourage clinicians to follow up patients in the long term.

CDK5RAP2 primary microcephaly is associated with hypothalamic, retinal and cochlear developmental defects.

BACKGROUND: Primary hereditary microcephaly (MCPH) comprises a large group of autosomal recessive disorders mainly affecting cortical development and resulting in a congenital impairment of brain growth. Despite the identification of >25 causal genes so far, it remains a challenge to distinguish between different MCPH forms at the clinical level. METHODS: 7 patients with newly identified mutations in CDK5RAP2 (MCPH3) were investigated by performing prospective, extensive and systematic clinical, MRI, psychomotor, neurosensory and cognitive examinations under similar conditions. RESULTS: All patients displayed neurosensory defects in addition to microcephaly. Small cochlea with incomplete partition type II was found in all cases and was associated with progressive deafness in 4 of them. Furthermore, the CDK5RAP2 protein was specifically identified in the developing cochlea from human fetal tissues. Microphthalmia was also present in all patients along with retinal pigmentation changes and lipofuscin deposits. Finally, hypothalamic anomalies consisting of interhypothalamic adhesions, a congenital midline defect usually associated with holoprosencephaly, was detected in 5 cases. CONCLUSION: This is the first report indicating that CDK5RAP2 not only governs brain size but also plays a role in ocular and cochlear development and is necessary for hypothalamic nuclear separation at the midline. Our data indicate that CDK5RAP2 should be considered as a potential gene associated with deafness and forme fruste of holoprosencephaly. These children should be given neurosensory follow-up to prevent additional comorbidities and allow them reaching their full educational potential. TRIAL REGISTRATION NUMBER: NCT01565005.

Loss of TNR causes a nonprogressive neurodevelopmental disorder with spasticity and transient opisthotonus.

PURPOSE: TNR, encoding Tenascin-R, is an extracellular matrix glycoprotein involved in neurite outgrowth and neural cell adhesion, proliferation and migration, axonal guidance, myelination, and synaptic plasticity. Tenascin-R is exclusively expressed in the central nervous system with highest expression after birth. The protein is crucial in the formation of perineuronal nets that ensheath interneurons. However, the role of Tenascin-R in human pathology is largely unknown. We aimed to establish TNR as a human disease gene and unravel the associated clinical spectrum. METHODS: Exome sequencing and an online matchmaking tool were used to identify patients with biallelic variants in TNR. RESULTS: We identified 13 individuals from 8 unrelated families with biallelic variants in TNR sharing a phenotype consisting of spastic para- or tetraparesis, axial muscular hypotonia, developmental delay, and transient opisthotonus. Four homozygous loss-of-function and four different missense variants were identified. CONCLUSION: We establish TNR as a disease gene for an autosomal recessive nonprogressive neurodevelopmental disorder with spasticity and transient opisthotonus and highlight the role of central nervous system extracellular matrix proteins in the pathogenicity of spastic disorders.

SLC13A3 variants cause acute reversible leukoencephalopathy and α-ketoglutarate accumulation.

OBJECTIVE: SLC13A3 encodes the plasma membrane Na+ /dicarboxylate cotransporter 3, which imports inside the cell 4 to 6 carbon dicarboxylates as well as N-acetylaspartate (NAA). SLC13A3 is mainly expressed in kidney, in astrocytes, and in the choroid plexus. We describe two unrelated patients presenting with acute, reversible (and recurrent in one) neurological deterioration during a febrile illness. Both patients exhibited a reversible leukoencephalopathy and a urinary excretion of α-ketoglutarate (αKG) that was markedly increased and persisted over time. In one patient, increased concentrations of cerebrospinal fluid NAA and dicarboxylates (including αKG) were observed. Extensive workup was unsuccessful, and a genetic cause was suspected. METHODS: Whole exome sequencing (WES) was performed. Our teams were connected through GeneMatcher. RESULTS: WES analysis revealed variants in SLC13A3. A homozygous missense mutation (p.Ala254Asp) was found in the first patient. The second patient was heterozygous for another missense mutation (p.Gly548Ser) and an intronic mutation affecting splicing as demonstrated by reverse transcriptase polymerase chain reaction performed in muscle tissue (c.1016 + 3A > G). Mutations and segregation were confirmed by Sanger sequencing. Functional studies performed on HEK293T cells transiently transfected with wild-type and mutant SLC13A3 indicated that the missense mutations caused a marked reduction in the capacity to transport αKG, succinate, and NAA. INTERPRETATION: SLC13A3 deficiency causes acute and reversible leukoencephalopathy with marked accumulation of αKG. Urine organic acids (especially αKG and NAA) and SLC13A3 mutations should be screened in patients presenting with unexplained reversible leukoencephalopathy, for which SLC13A3 deficiency is a novel differential diagnosis. ANN NEUROL 2019;85:385-395.

Paediatric-onset neuronal ceroid lipofuscinosis: first symptoms and presentation at diagnosis.

Neuronal ceroid lipofuscinoses (NCLs) are rare, progressive disorders. Through this series of 20 patients with NCL, we illustrate differences between subtypes in their presenting symptoms and clinical, imaging, and electrophysiological results to raise awareness of symptom diversity. Data were available on presenting symptoms, genetics, magnetic resonance imaging (MRI), electroencephalography (including with low-frequency intermittent photic stimulation), visual responses, and electron microscopy. Causal mutations were identified in 10 patients. Eleven patients had neuronal ceroid lipofuscinosis type 2 (CLN2) disease and their most common presenting symptom was seizures, although motor and language defects were also reported. Five patients with CLN2 disease showed abnormalities at initial MRI, but only three showed a photic response with low-frequency stimulation. Seizures were not as common a presenting symptom in other NCL subtypes. Patients with NCLs present with diverse symptoms, which may not be characteristic in early disease stages. These signs and symptoms should lead to rapid diagnostic confirmatory testing for NCLs. WHAT THIS PAPER ADDS: Disease presentation is not uniform for neuronal ceroid lipofuscinoses. Characteristic clinical test results may not be identified in early disease stages.

Association of Matched Sibling Donor Hematopoietic Stem Cell Transplantation With Transcranial Doppler Velocities in Children With Sickle Cell Anemia.

Importance: In children with sickle cell anemia (SCA), high transcranial Doppler (TCD) velocities are associated with stroke risk, which is reduced by chronic transfusion. Whether matched sibling donor hematopoietic stem cell transplantation (MSD-HSCT) can reduce velocities in patients with SCA is unknown. Objective: To determine the association of MSD-HSCT with TCD velocities as a surrogate for the occurrence of ischemic stroke in children with SCA. Design, Setting, and Participants: Nonrandomized controlled intervention study conducted at 9 French centers. Patients with SCA were enrolled between December 2010 and June 2013, with 3-year follow-up ending in January 2017. Children with SCA were eligible if younger than 15 years, required chronic transfusions for persistently elevated TCD velocities, and had at least 1 sibling without SCA from the same 2 parents. Families agreed to HLA antigen typing and transplantation if a matched sibling donor was identified or to standard care in the absence of a matched sibling donor. Exposures: MSD-HSCT (n = 32), compared with standard care (n = 35) (transfusions for ≥1 year with potential switch to hydroxyurea thereafter), using propensity score matching. Main Outcomes and Measures: The primary outcome was the highest time-averaged mean of maximum velocities in 8 cerebral arteries, measured by TCD (TCD velocity) at 1 year. Twenty-five of 29 secondary outcomes were analyzed, including the highest TCD velocity at 3 years and normalization of velocities (<170 cm/s) and ferritin levels at 1 and 3 years. Results: Sixty-seven children with SCA (median age, 7.6 years; 35 girls [52%]) were enrolled (7 with stroke history). In the matched sample, highest TCD velocities at 1 year were significantly lower on average in the transplantation group (129.6 cm/s) vs the standard care group (170.4 cm/s; difference, -40.8 cm/s [95% CI, -62.9 to -18.6]; P < .001). Of the 25 analyzed secondary end points, 4 showed significant differences, including the highest TCD velocity at 3 years (112.4 cm/s in the transplantation group vs 156.7 cm/s in the standard care group; difference, -44.3 [95% CI, -71.9 to -21.1]; P = .001); normalization rate at 1 year (80.0% in the transplantation group vs 48.0% in the standard care group; difference, 32.0% [95% CI, 0.2% to 58.6%]; P = .045); and ferritin levels at 1 year (905 ng/mL in the transplantation group vs 2529 ng/mL in the standard care group; difference, -1624 [95% CI, -2370 to -879]; P < .001) and 3 years (382 ng/mL in the transplantation group vs 2170 ng/mL in the standard care group; difference, -1788 [95% CI, -2570 to -1006]; P < .001). Conclusions and Relevance: Among children with SCA requiring chronic transfusion because of persistently elevated TCD velocities, MSD-HSCT was significantly associated with lower TCD velocities at 1 year compared with standard care. Further research is warranted to assess the effects of MSD-HSCT on clinical outcomes and over longer follow-up. Trial Registration: ClinicalTrials.gov Identifier: NCT01340404.

Autosomal recessive primary microcephaly due to ASPM mutations: An update.

Autosomal recessive microcephaly or microcephaly primary hereditary (MCPH) is a genetically heterogeneous neurodevelopmental disorder characterized by a reduction in brain volume, indirectly measured by an occipitofrontal circumference (OFC) 2 standard deviations or more below the age- and sex-matched mean (-2SD) at birth and -3SD after 6 months, and leading to intellectual disability of variable severity. The abnormal spindle-like microcephaly gene (ASPM), the human ortholog of the Drosophila melanogaster "abnormal spindle" gene (asp), encodes ASPM, a protein localized at the centrosome of apical neuroprogenitor cells and involved in spindle pole positioning during neurogenesis. Loss-of-function mutations in ASPM cause MCPH5, which affects the majority of all MCPH patients worldwide. Here, we report 47 unpublished patients from 39 families carrying 28 new ASPM mutations, and conduct an exhaustive review of the molecular, clinical, neuroradiological, and neuropsychological features of the 282 families previously reported (with 161 distinct ASPM mutations). Furthermore, we show that ASPM-related microcephaly is not systematically associated with intellectual deficiency and discuss the association between the structural brain defects (strong reduction in cortical volume and surface area) that modify the cortical map of these patients and their cognitive abilities.

Mitochondrial acetoacetyl-CoA thiolase deficiency: basal ganglia impairment may occur independently of ketoacidosis.

BACKGROUND: Mitochondrial acetoacetyl-CoA thiolase (T2) deficiency affects ketone body and isoleucine catabolism. Neurological impairment may occur secondary to ketoacidotic episodes. However, we observed neuromotor abnormalities without ketoacidotic events in two T2-deficient families. We hypothesized that the neurological signs were related to the genetic defect and may occur independently of ketoacidotic episodes. We therefore conducted a retrospective review on a French T2-deficient patient series searching for neuromotor impairment. METHODS: In total, 26 cases were retrospectively analysed for clinical, biological and neuroimaging data. RESULTS: Neurological findings were observed for 6/26 (23%) patients. Among these, two had never experienced ketoacidotic episodes, though they developed extrapyramidal signs with putamen involvement. Two of the other four patients developed neurological abnormalities before the first ketoacidotic crisis, with putamen involvement in one case. The third patient developed extrapyramidal symptoms more than 10 years after the initial decompensation with globus pallidus involvement. The last patient developed extrapyramidal signs immediately after a severe ketoacidotic crisis with putaminal lesions. CONCLUSIONS: Most T2-deficient patients achieved normal neurodevelopment. However, on account of the role of T2 in isoleucine catabolism, these patients are potentially exposed to accumulation of toxic isoleucine-derived metabolites, which may contribute to neurological impairment. Our findings confirm previous observations that neurological symptoms in T2 deficiency may occur unrelated to ketoacidosis. The role of protein restriction as a preventive measure against neurological symptoms could not be established in this study and deserves further evaluation. Long-term follow-up data on children diagnosed by newborn screening may clarify the pathogenesis of this neurometabolic association.

High-resolution heavily T2-weighted magnetic resonance imaging for evaluation of the pituitary stalk in children with ectopic neurohypophysis.

BACKGROUND: In anterior pituitary deficiency, patients with non visible pituitary stalk have more often multiple deficiencies and persistent deficiency than patients with visible pituitary stalk. OBJECTIVE: To compare the diagnostic value of a high-resolution heavily T2-weighted sequence to 1.5-mm-thick unenhanced and contrast-enhanced sagittal T1-weighted sequences to assess the presence of the pituitary stalk in children with ectopic posterior pituitary gland. MATERIALS AND METHODS: We retrospectively evaluated the MRI data of 14 children diagnosed with ectopic posterior pituitary gland between 2010 and 2014. We evaluated the presence of a pituitary stalk using a sagittal high-resolution heavily T2-weighted sequence and a 1.5-mm sagittal T1-weighted turbo spin-echo sequence before and after contrast medium administration. RESULTS: A pituitary stalk was present on at least one of the sequences in 10 of the 14 children (71%). T2-weighted sequence depicted the pituitary stalk in all 10 children, whereas the 1.5-mm-thick T1-weighted sequence depicted 2/10 (20%) before contrast injection and 8/10 (80%) after contrast injection (P=0.007). CONCLUSION: Compared with 1.5-mm-thick contrast-enhanced T1-weighted sequences, high-resolution heavily T2-weighted sequence demonstrates better sensitivity in detecting the pituitary stalk in children with ectopic posterior pituitary gland, suggesting that contrast injection is unnecessary to assess the presence of a pituitary stalk in this setting.

Apparent diffusion coefficient measurements of the fetal brain during the third trimester of pregnancy: how reliable are they in clinical practice?

OBJECTIVE: The objective of this study was to determine the reproducibility, the inter-hemispheric difference and the reference apparent diffusion coefficient (ADC) values of the fetal brain according to gestational age. METHOD: One hundred and one normal fetal brain (29.4-38.4 weeks) were analysed with diffusion-weighted MR imaging. ADC was measured in frontal white matter (FWM), occipital white matter (OWM), centrum semi-ovale (CSO), basal ganglia (BG), cerebellar hemisphere (CBM) and pons. ADC ratios (fronto-occipital, fronto-cerebellar and occipito-cerebellar) were calculated. Inter-observer reproducibility was assessed on 27 studies, using intra-class correlation coefficient and Bland-Altman plot. Inter-hemispheric difference was evaluated with Bland-Altman plot. Gestation-specific reference intervals were estimated for each brain region. RESULTS: Inter-observer bias was near zero. Limits of agreement (LOA) were clinically acceptable (-0.17; 0.20 to -0.38; 0.31 × 10(-3) mm(2) /s) for all brain regions except for CSO and pons. Inter-hemispheric bias was near zero. Smallest LOA were for FWM (±0.09 mm(2) /s) and BG (±0.019 mm(2) /s). ADC values decreased, whereas ADC ratio increased with gestational age, reflecting normal maturation. Fronto-occipital, fronto-cerebellar and occipito-cerebellar ratios were consistently above 0.8, 1 and 1, respectively. CONCLUSION: The fetal brain regions with the highest reproducibility and smallest inter-hemispheric differences are the frontal, occipital, cerebellar white matter and BG. ADC ratio could be useful to assess differential temporo-spatial maturation.

Extracranial carotid arteriopathy in stroke-free children with sickle cell anemia: detection by submandibular Doppler sonography.

BACKGROUND: Cerebral vasculopathy is a serious complication of sickle cell anemia. Overt strokes are largely due to intracranial arteriopathy, detected by routine transcranial Doppler and largely prevented through chronic transfusions. As extracranial internal carotid artery arteriopathy was considered rare, it has not been routinely assessed in sickle cell anemia. Recent cases of overt strokes associated with stenosis/occlusion of the extracranial portion of the internal carotid artery prompted us to include extracranial internal carotid artery assessment to our transcranial Doppler sonography protocol. OBJECTIVE: The aim of the study was to perform a cross-sectional study in children with sickle cell anemia to evaluate Doppler flow patterns of the extracranial internal carotid arteries and to assess potential associated factors. MATERIALS AND METHODS: Between June 2011 and April 2012, 435 consecutive stroke-free children with sickle cell anemia (200/235 M/F, median age: 7.9 years) were assessed for extracranial internal carotid artery using a 2-MHz transcranial Doppler sonography probe via a submandibular window during routine transcranial Doppler sonography visits. The course of both extracranial internal carotid artery was assessed by color Doppler mapping, and the highest flow velocity was recorded after insonation of the entire length of the artery and analyzed. Intra- and extracranial MR angiographies were available in 104/435 subjects for comparison. RESULTS: Mean (SD) extracranial internal carotid artery time-averaged mean of maximum velocity was 96 (40) cm/s. Extracranial internal carotid artery tortuosities were echo-detected in 25% cases and were more frequent in boys (33% vs.18%; P < 0.001). Velocity ≥160 cm/s in at least one extracranial internal carotid artery was found in 45 out of 435 patients with sickle cell anemia (10.3%) and was highly predictive of MR angiography stenosis. Simultaneous abnormal intracranial velocity (≥200 cm/s) was recorded in 5/45 patients, while 40 patients had isolated extracranial internal carotid artery velocity ≥160 cm/s. Low hemoglobin (odds ratio: 1.9/g/dL, 95% confidence interval (CI): 1.3-2.9; P = 0.001) and tortuosities (odds ratio: 19.2, 95% CI: 7.1-52.6; P < 0.001) were significant and independent associated factors for isolated extracranial internal carotid artery velocities ≥160 cm/s. CONCLUSION: Adding extracranial internal carotid artery evaluation via the submandibular window to transcranial Doppler sonograpy allowed us to detect 10.3% patients at risk for extracranial internal carotid arteriopathy. Further studies are needed to evaluate the prognosis of these anomalies.

PACS2 pathogenic variant associated with malformation of cortical development and epilepsy.

PACS2 pathogenic variants are associated with an autosomal dominant syndrome (OMIM DEE66), associating developmental and epileptic encephalopathy, facial dysmorphism, and cerebellar dysgenesis. However, no malformation of cortical development has been reported yet. We report here a seven-year-old child with a history of infantile epileptic spasm syndrome and a right insular polymicrogyria and pachygyria due to de novo PACS2 recurrent mutation c.625G>A (p.Glu209Lys). Our observation raises the question of the role of PACS2 in the cortical development. It also reminds the importance of cerebellar anomalies in the recognition of PACS-related DEE.

Biallelic variants in DAP3 result in reduced assembly of the mitoribosomal small subunit with altered intrinsic and extrinsic apoptosis and a Perrault syndrome-spectrum phenotype.

The mitoribosome synthesizes 13 protein subunits of the oxidative phosphorylation system encoded by the mitochondrial genome. The mitoribosome is composed of 12S rRNA, 16S rRNA and 82 mitoribosomal proteins encoded by nuclear genes. To date, variants in 12 genes encoding mitoribosomal proteins are associated with rare monogenic disorders, and frequently show combined oxidative phosphorylation deficiency. Here, we describe five unrelated individuals with biallelic variants in the DAP3 nuclear gene encoding mitoribosomal small subunit 29 (MRPS29), with variable clinical presentations ranging from Perrault syndrome (sensorineural hearing loss and ovarian insufficiency) to an early childhood neurometabolic phenotype. Assessment of respiratory chain function and proteomic profiling of fibroblasts from affected individuals demonstrated reduced MRPS29 protein levels, and consequently decreased levels of additional protein components of the mitoribosomal small subunit, associated with a combined complex I and IV deficiency. Lentiviral transduction of fibroblasts from affected individuals with wild-type DAP3 cDNA increased DAP3 mRNA expression, and partially rescued protein levels of MRPS7, MRPS9 and complex I and IV subunits, demonstrating the pathogenicity of the DAP3 variants. Protein modelling suggested that DAP3 disease-associated missense variants can impact ADP binding, and in vitro assays demonstrated DAP3 variants can consequently reduce both intrinsic and extrinsic apoptotic sensitivity, DAP3 thermal stability and DAP3 GTPase activity. Our study presents genetic and functional evidence that biallelic variants in DAP3 result in a multisystem disorder of combined oxidative phosphorylation deficiency with pleiotropic presentations, consistent with mitochondrial dysfunction.

Is fetal cerebral MRI worthwhile in antenatally diagnosed isolated cleft lip with or without palate?

OBJECTIVE: This study aims to evaluate the use of fetal brain magnetic resonance imaging (MRI) following an antenatal sonographic diagnosis of isolated cleft lip with or without cleft palate (CL/P). METHOD: This was a retrospective study of 92 fetuses antenatally diagnosed with isolated CL/P on screening ultrasound. All patients underwent expert diagnostic antenatal ultrasound, fetal brain MRI, and karyotype analysis. RESULTS: Five cases were excluded from the study as associated abnormalities were detected on expert ultrasound: corpus callosum agenesis (n = 1), retrognathism (n = 3), and ectrodactyly (n = 1). Fetal MRI diagnosed unsuspected midline cerebral abnormalities in four out of the 87 remaining cases (4.6%): vermis agenesis (n = 1), isolated arhinencephaly (n = 2), and suspicion of pituitary abnormality (n = 1). All karyotype analyses were normal. CONCLUSION: In CL/P, the incidence of associated cerebral abnormalities overlooked on ultrasound is 4.6%. Careful evaluation of midline structures by expert ultrasound in CL/P is necessary and may be sufficient. MRI can be useful if the US examination is limited or in case of family history. However, the choice to proceed to fetal MRI may vary from institution to institution.

Spectral-based thickness profiling of the corpus callosum enhances anomaly detection in fetal alcohol spectrum disorders.

Introduction: Fetal alcohol spectrum disorders (FASD) range from fetal alcohol syndrome (FAS) to non-syndromic forms (NS-FASD). The neuroanatomical consequences of prenatal alcohol exposure are mainly the reduction in brain size, but also focal abnormalities such as those of the corpus callosum (CC). We previously showed a narrowing of the CC for brain size, using manual measurement and its usefulness to improve diagnostic certainty. Our aim was to automate these measurements of the CC and identify more recurrent abnormalities in FAS subjects, independently of brain size reduction. Methods: We developed a fast, automated, and normalization-free method based on spectral analysis to generate thicknesses of the CC continuously and at singular points (genu, body, isthmus, and splenium), and its length (LCC). We applied it on midsagittal section of the CC extracted from T1-anatomical brain MRI of 89 subjects with FASD (52 FAS, 37 NS-FASD) and 126 with typically development (6-20 y-o). After adjusting for batch effect, we compared the mean profiles and thicknesses of the singular points across the 3 groups. For each parameter, we established variations with age (growth charts) and brain size in the control group (scaling charts), then identified participants with abnormal measurements (<10th percentile). Results: We confirmed the slimming of the posterior half of the CC in both FASD groups, and of the genu section in the FAS group, compared to the control group. We found a significant group effect for the LCC, genu, median body, isthmus, and splenium thicknesses (p < 0.05). We described a body hump whose morphology did not differ between groups. According to the growth charts, there was an excess of FASD subjects with abnormal LCC and isthmus, and of FAS subjects with abnormal genu and splenium. According to the scaling charts, this excess remained only for LCC, isthmus and splenium, undersized for brain size. Conclusion: We characterized size-independent anomalies of the posterior part of the CC in FASD, with an automated method, confirming and extending our previous study. Our new tool brings the use of a neuroanatomical criterion including CC damage closer to clinical practice. Our results suggest that an FAS signature identified in NS-FASD, could improve diagnosis specificity.