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Background: This study aimed to explore the genetic basis of a fetus with ultrasound indicating a thickening of the nuchal translucency (NT) and a choroid plexus cyst., Methods: Fetal amniotic fluid and peripheral blood were collected for a G-banding karyotype analysis and single nucleotide polymorphism array (SNP-array) detection., Results: The chromosome karyotypes of the fetus and its parents were normal. SNP-array showed the fetus had carried 277 kb microdeletion at 14q11.2, which was a new mutation. After the induced abortion, the fetus was diagnosed with macrocephaly., Conclusions: A prenatal diagnosis of a fetus with 14q11.2 microdeletion-induced intrauterine growth retardation was confirmed, which has provided guidance for the subsequent pregnancy.

Objective: The aim of this study was to provide a full characterization of a cohort of 11 pediatric patients diagnosed with PTEN hamartoma tumor syndrome (PHTS)., Patients and Methods: Eleven patients with genetic diagnostic of PHTS were recruited between February 2019 and April 2023. Clinical, imaging, demographic, and genetic data were retrospectively collected from their hospital medical history., Results: Regarding clinical manifestations, macrocephaly was the leading sign, present in all patients. Frontal bossing was the most frequent dysmorphism. Neurological issues were present in most patients. Dental malformations were described for the first time, being present in 27% of the patients. Brain MRI showed anomalies in 57% of the patients. No tumoral lesions were present at the time of the study. Regarding genetics, 72% of the alterations were in the tensin-type C2 domain of PTEN protein. We identified four PTEN genetic alterations for the first time., Conclusions: PTEN mutations appear with a wide variety of clinical signs and symptoms, sometimes associated with phenotypes which do not fit classical clinical diagnostic criteria for PHTS. We recommend carrying out a genetic study to establish an early diagnosis in children with significant macrocephaly. This facilitates personalized monitoring and enables anticipation of potential PHTS-related complications., (© 2024. The Author(s).)

Abusive head trauma (AHT) is a significant cause of morbidity and mortality for infants. Determining when to pursue a complete physical abuse evaluation can be difficult, especially for nonspecific findings or when a child appears clinically well. This retrospective study of 7 cases sought to describe the presentation, evaluation, and diagnoses for infants with abnormal subdural collections identified on cranial ultrasound for macrocephaly, and to determine how frequently AHT is diagnosed. The results of this study showed that while each patient presented due to asymptomatic macrocephaly, the extent of the workup varied greatly. In addition, no infants had suspicious injuries for abuse during the initial evaluation or the year following. In summary, among the 7 patients seen for asymptomatic macrocephaly with possible subdural hemorrhage, there were very inconsistent child abuse workups. There needs to be a standardized clinical guideline for this specific patient population involving a child abuse pediatric evaluation., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

The syndrome of megalencephaly, mega corpus callosum (MEG-MegaCC) accompanied by complete lack of motor development is a rare condition with only few sporadic cases having been reported in the literature. In this paper, we describe a child from non-consanguineous parents presenting with MegaCC, psychomotor retardation, and language impairment linked to MEG-MegaCC syndrome. Genetic analysis, radiological findings, and detailed neurological phenotype of MEG-MegaCC syndrome with its overlapping syndromes would allow for a better classification of the disease spectrum., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: The subarachnoid space (SAS) is a potential space surrounding the brain where the cerebrospinal fluid (CSF) flows. Previous work demonstrated how the SAS width changes during pregnancy and measured the normal values per gestational week., Objectives: Studying the ratio between the fetal brain volume (STV) and the SAS width (SS ratio), as measured via fetal magnetic resonance imaging (MRI) in different fetal pathologies - macrocephaly and microcephaly, and studying the correlation between this ratio and the gestational week., Methods: A retrospective study was conducted on 77 fetuses that underwent fetal MRI scans during gestational weeks 29-37, in three groups: 23 normocephaly, 27 macrocephaly, and 27 microcephaly. SAS width was measured in 10 points via fetal MRI scans, and a ratio was calculated between the width and STV., Results: The SS ratio is largest in microcephaly group and smallest in normocephaly group, with the macrocephaly group between them. All comparisons were statistically significant except between the macrocephaly and normocephaly groups. There was a strong positive correlation between SS ratio and week of gestation., Conclusions: The SS ratio is statistically different between normocephalic fetuses and fetuses with macrocephaly or microcephaly. From week 29 this ratio enlarges with gestational age., Discussion: The SAS affects the fetal head circumference, an important parameter of fetal growth, thus we decided to study the SS ratio in pathologies of the head circumference. Previous work demonstrated how the STV and the SAS width expand starting at a specific gestational age, thus the gestational week also affects the SS ratio. Summary: The SS ratio is affected by pathologies of the fetal head circumference and by gestational age.

Background: Macrocephaly is present in 2.3% of children with important neurosurgical conditions in the differential diagnosis. The objective of this study was to identify clinical associations with actionable imaging findings among children with head imaging for macrocephaly., Methods: We conducted a case-control study of head imaging studies ordered for macrocephaly among children 24 months and younger in a multistate children's health system. Four neurosurgeons reviewed the images, determining cases to be a 'concern' if neurosurgical follow-up or intervention was indicated. Electronic health records were reviewed to collect patient-level data and to determine if surgery was performed. Controls were matched 3:1 to cases of 'concern' in a multivariate model using conditional logistic regression., Results: In the study sample (n = 1293), 46 (4%) were concern cases, with 15 (1%) requiring surgery. Significant clinical factors associated with neurosurgical concern were bulging fontanel [aOR 7.47, (95% CI: 2.28-24.44), P < 0.001], prematurity [aOR 21.26, (95% CI: 3.76-120.21), P < 0.001], any delay [aOR 2.67, (95% CI: 1.13-6.27), P = 0.03], and head-weight Z-score difference (W&#95;diff, defined as the difference between the Z-scores of head circumference and weight) [aOR 1.70, (95% CI: 1.22-2.37), P = 0.002]., Conclusions: Head imaging for macrocephaly identified few patients with findings of concern and fewer requiring surgery. A greater head-weight Z-score difference appears to represent a novel risk factor for neurosurgical follow-up or intervention., (© 2023. The Author(s).)

Background: Inactivating mutations in PTEN are among the most common causes of megalencephaly. Activating mutations in other nodes of the PI3K/AKT/MTOR signaling pathway are recognized as a frequent cause of cortical brain malformations. Only recently has PTEN been associated with cortical malformations, and analyses of their prognostic significance have been limited., Methods: Retrospective neuroimaging analysis and detailed chart review were conducted on 20 participants identified with pathogenic or likely pathogenic mutations in PTEN and a cortical brain malformation present on brain magnetic resonance imaging., Results: Neuroimaging analysis revealed four main cerebral phenotypes-hemimegalencephaly, focal cortical dysplasia, polymicrogyria (PMG), and a less severe category, termed "macrocephaly with complicated gyral pattern" (MCG). Although a high proportion of participants (90%) had neurodevelopmental findings on presentation, outcomes varied and were favorable in over half of participants. Consistent with prior work, 39% of participants had autism spectrum disorder and 19% of participants with either pure-PMG or pure-MCG phenotypes had epilepsy. Megalencephaly and systemic overgrowth were common, but other systemic features of PTEN-hamartoma tumor syndrome were absent in over one-third of participants., Conclusions: A spectrum of cortical dysplasias is present in individuals with inactivating mutations in PTEN. Future studies are needed to clarify the prognostic significance of each cerebral phenotype, but overall, we conclude that despite a high burden of neurodevelopmental disease, long-term outcomes may be favorable. Germline testing for PTEN mutations should be considered in cases of megalencephaly and cortical brain malformations even in the absence of other findings, including cognitive impairment., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Severe macrocephaly can still be found in developing countries. This condition is usually caused by neglected hydrocephalus and can cause a lot of morbidities. Cranial vault reconstruction cranioplasty is the main treatment option for severe macrocephaly. Holoprosencephaly is often seen with features of microcephaly. Hydrocephalus should be considered as the main cause in HPE patients with features of macrocephaly. In this report, we present a rare case of cranial vault reduction cranioplasty procedure in patient with severe macrocephaly due to holoprosencephaly and subdural hygroma., Case Description: A 4-year-10-month-old Indonesian boy was admitted with head enlargement since birth. He had a history of VP shunt placement when he was 3 months old. But the condition was neglected. Preoperative head CT showed massive bilateral subdural hygroma that compressed brain parenchyma caudally. From the craniometric calculation, the occipital frontal circumference was 70.5 cm with prominent vertex expansion, the distance between nasion to inion was 11.91 cm and the vertical height was 25.59 cm. The preoperative cranial volume was 24.611 cc. The patient underwent subdural hygroma evacuation and cranial vault reduction cranioplasty. The postoperative cranial volume was 10.468 cc., Conclusion: Subdural hygroma can be a rare cause of severe macrocephaly in holoprosencephaly patients. Cranial vault reduction cranioplasty and subdural hygroma evacuation is still the main treatment option. Our procedure successfully reduces significant cranial volume (57.46% volume reduction)., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare leukodystrophy characterized by early-onset macrocephaly and progressive white matter vacuolation. The MLC1 protein plays a role in astrocyte activation during neuroinflammation and regulates volume decrease following astrocyte osmotic swelling. Loss of MLC1 function activates interleukin (IL)-1β-induced inflammatory signals. Theoretically, IL-1 antagonists (such as anakinra and canakinumab) can slow the progression of MLC. Herein, we present two boys from different families who had MLC due to biallelic MLC1 gene mutations and were treated with the anti-IL-1 drug anakinra., Methods: Two boys from different families presented with megalencephaly and psychomotor retardation. Brain magnetic resonance imaging findings in both patients were compatible with the diagnosis of MLC. The diagnosis of MLC was confirmed via Sanger analysis of the MLC1 gene. Anakinra was administered to both patients. Volumetric brain studies and psychometric evaluations were performed before and after anakinra treatment., Results: After anakinra therapy, brain volume in both patients decreased significantly and cognitive functions and social interactions improved. No adverse effects were observed during anakinra therapy., Conclusions: Anakinra or other IL-1 antagonists can be used to suppress disease activity in patients with MLC; however, the present findings need to be confirmed via additional research., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Macrocephaly, defined as a head circumference greater than 2 standard deviations above the mean, is a relatively common presenting symptom in the pediatric population at routine well-child examinations and a common indication for neuroimaging. Multiple imaging modalities are complementary in evaluating macrocephaly, including US, CT, and MRI. The differential diagnosis for macrocephaly is broad, and many disease processes lead to macrocephaly only when the sutures are open. In patients with closed sutures, these entities instead lead to increased intracranial pressure, according to the Monroe-Kellie hypothesis, which states that there is an equilibrium between intracranial constituents due to the fixed intracranial volume. The authors describe a useful paradigm for classifying macrocephaly by identifying which of the four components of the cranium (ie, cerebrospinal fluid, blood and vasculature, brain parenchyma, or calvarium) has an increased volume. Patient age, additional imaging findings, and clinical symptoms are also useful features. Most cases in the pediatric population are due to increased cerebrospinal fluid spaces, such as benign enlargement of the subarachnoid space, which must be carefully distinguished from subdural fluid collections in patients with accidental or nonaccidental trauma. Other common causes of macrocephaly are discussed, including hydrocephalus secondary to an aqueductal web, hemorrhage, or a neoplasm. The authors also provide information on some of the rarer diseases for which imaging may provide the impetus for genetic testing (eg, overgrowth syndromes and metabolic disorders). © RSNA, 2023 Quiz questions for this article are available through the Online Learning Center.

Hemimegalencephaly (HME) is a rare neurological diagnosis defined as hamartomatous overgrowth of one cerebral hemisphere. The hypothesised pathogenesis is due to an increased number or size of neural cells; however, the exact mechanism can vary widely, depending on the underlying aetiology. We report a case outlining the prenatal diagnostic process and obstetric considerations for delivering an infant with HME secondary to megalencephaly-capillary malformation syndrome. After diagnosis, our patient was induced and delivered at 37 weeks of gestation via operative vaginal delivery. To our knowledge, this is the first report describing the course from prenatal diagnosis through delivery of a fetus with HME., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Macrocephaly is a common diagnosis in the pediatric population, particularly in the infantile time period. There is a wide range of causes of macrocephaly, from benign to malignant, for which imaging plays a key role in the diagnosis and clinical guidance. Our aim is to review the distinct and prevalent neuroimaging findings in the evaluation of the macrocephalic infant., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objective: Benign Enlargement of the Subarachnoid Spaces in Infancy (BESSI) is a common finding during workup for progressive macrocephaly. BESSI has been associated with slightly higher prevalence of subdural (SD) spaces and a risk for developing subdural hematoma. This study utilizes fast brain magnetic resonance imaging (MRI) to investigate the prevalence of visible SD spaces in BESSI., Methods: A retrospective review was performed for all pediatric patients who underwent brain MRI for macrocephaly. Patients with a diagnosis of BESSI were included in the study. A total of 109 patients met the inclusion criteria. Patient demographics were collected, and images were reviewed for size of subarachnoid, visible SD spaces, and ventricle size. Descriptive and inferential statistics were performed., Results: The average age was 8 ± 4.6 months, 64 (59%) were male, and 55 patients had no previous medical history (50%). Sixty-seven percent of all patients were identified to have visible SD spaces. Eleven patients had confirmed SD hematomas; 1 patient was deemed to have abusive head trauma. Visible SD spaces were associated with younger age (6.9 months). Thirty-one patients with visible SD spaces had follow-up MRI, with complete resolution by 33 months., Conclusions: BESSI is a self-limiting pathology that has been associated with visible SD spaces and potential risk for SD hemorrhages. We report a high prevalence of visible SD spaces within BESSI through utilization of fast brain MRI. These spaces may contribute to the higher rate of incidental subdural hematoma in this population., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Competing Interests: Competing interests: None declared.

Macrocephaly is a clinical term defined as an occipitofrontal circumference more than two standard deviations above the mean. It is present in 5% of children and is a common indication for imaging studies. There are multiple causes of macrocephaly; most of them are benign. Nevertheless, in some cases, macrocephaly is the clinical manifestation of a condition that requires timely medical and/or surgical treatment. The importance of imaging studies lies in identifying the patients who would benefit from treatment. Children with macrocephaly associated with neurologic alterations, neurocutaneous stigmata, delayed development, or rapid increase of the circumference have a greater risk of having disease. By contrast, parental macrocephaly is predictive of a benign condition. Limiting imaging studies to patients with increased risk makes it possible to optimize resources and reduce unnecessary exposure to tests., (Copyright © 2021 SERAM. Published by Elsevier España, S.L.U. All rights reserved.)

Megalencephaly-capillary malformation-polymicrogyria syndrome (MCAP) is a rare disorder that arises as a result of a somatic mosaic mutation in the PIK3CA gene. It characteristically presents with postnatal or congenital megalencephaly, cutaneous capillary malformations, postaxial polydactyly and often segmental or focal body overgrowth. We report a 7-year-old boy with known MCAP who was diagnosed at around 10 months old with a mosaic change in the PIK3CA gene. He was found to have hall-mark clinical signs; macrocephaly and four-limb postaxial polydactyly. Since diagnosis, he has had multiple clinical features, most of which typically present in children with MCAP. He has now been diagnosed with autism spectrum disorder (ASD), demand avoidance and is under assessment for attention deficit hyperactivity disorder. Although some cases have been raised to the M-CM Network, to our knowledge this is the first case of ASD in MCAP to be reported in the literature., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Bachmann-Bupp syndrome (BABS) is a rare syndrome caused by gain-of-function variants in the C-terminus of ornithine decarboxylase (ODC coded by the ODC1 gene). BABS is characterized by developmental delay, macrocephaly, macrosomia, and an unusual pattern of non-congenital alopecia. Recent diagnosis of four more BABS patients provides further characterization of the phenotype of this syndrome including late-onset seizures in the oldest reported patient at 23 years of age, representing the first report for this phenotype in BABS. Neuroimaging abnormalities continue to be an inconsistent feature of the syndrome. This may be related to the yet unknown impact of ODC/polyamine dysregulation on the developing brain in this syndrome. Variants continue to cluster, providing support to a universal biochemical mechanism related to elevated ODC protein, enzyme activity, and abnormalities in polyamine levels. Recommendations for medical management can now be suggested as well as the potential for targeted molecular or metabolic testing when encountering this unique phenotype. The natural history of this syndrome will evolve with difluoromethylornithine (DFMO) therapy and raise new questions for further study and understanding., (© 2021 The Authors. American Journal of Medical Genetics Part A published by Wiley Periodicals LLC.)

Purpose: We describe our series of 4 patients with megalencephaly-capillary malformation syndrome (MCAP) and review the literature in order to assess the optimal treatment for the associated hydrocephalus., Methods: We review our institutional series of hydrocephalus associated with MCAP and review the literature, analyzing the causes that could originate the hydrocephalus and the different types of treatments proposed for them., Results: Of our patients treated with ventriculoperitoneal (VP) shunt, one suffered a surgical revision of the shunt and died due to a cranial trauma unrelated to her syndrome or the previous shunt surgery, and the other did not undergo surgical revisions until the end of her follow-up. Our patients treated with endoscopic third ventriculostomy (ETV) have improved their symptomatology and have not suffered of any complications related to the hydrocephalus after the ETV surgery., Conclusions: We update the treatment of MCAP-associated hydrocephalus and propose ETV as a valid treatment, as it seems a safe procedure with a low rate of complications., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Macrocephaly is a common finding in infants and is often idiopathic or familial. In the absence of clinical signs and symptoms, it can be difficult to determine when concern for underlying pathology is justified., Objectives: The objectives of this study were to determine the utility of screening head ultrasound (US) in asymptomatic infants with macrocephaly and to identify clinical factors associated with significant US findings., Materials and Methods: A 20-year retrospective review was performed of infants undergoing head US for macrocephaly or rapidly increasing head circumference. Data collected included age, gender, head circumference at birth and at the time of US, specialty of the ordering physician, US findings, computed tomography (CT) or magnetic resonance imaging (MRI) findings, and clinical course including interventions., Results: Four hundred and forty infants met inclusion criteria. Two hundred and eighty studies (64%) were found to be normal, 137 (31%) had incidental findings, 17 (3.8%) had indeterminate but potentially significant findings, and 6 (1.4%) had significant findings. Twenty of the 23 infants with indeterminate or significant findings had subsequent CT or MRI. This confirmed significant findings in eight infants (1.8%): three subdural hematomas, two intracranial tumors, two aqueductal stenoses, and one middle fossa cyst. Five of the eight infants required surgical procedures. The only statistically significant association found with having a significant finding on head US was head circumference at birth., Conclusion: Ultrasound is a useful initial study to evaluate infantile macrocephaly, identifying several treatable causes in our study and, when negative, effectively excluding significant pathology.

Enlarged subarachnoid spaces are a common finding in infants and young children imaged for macrocephaly or an enlarging head circumference, and benign enlargement of the subarachnoid spaces is often diagnosed. Infrequently, presumed "spontaneous" subdural hemorrhages or subdural collections might complicate these enlarged subarachnoid spaces. Children with large bilateral subdural collections might also present for imaging with macrocephaly. Each scenario potentially raises concerns for prior injury because subdural hemorrhage is a frequent finding in children with abusive head trauma.

Megalencephaly-CApillary malformation-Polymicrogyria (MCAP) syndrome results from somatic mosaic gain-of-function variants in PIK3CA. Main features are macrocephaly, somatic overgrowth, cutaneous vascular malformations, connective tissue dysplasia, neurodevelopmental delay, and brain anomalies. The objectives of this study were to describe the clinical and radiological features of MCAP, to suggest relevant clinical endpoints applicable in future trials of targeted drug therapy. Based on a French collaboration, we collected clinical features of 33 patients (21 females, 12 males, median age of 9.9 years) with MCAP carrying mosaic PIK3CA pathogenic variants. MRI images were reviewed for 21 patients. The main clinical features reported were macrocephaly at birth (20/31), postnatal macrocephaly (31/32), body/facial asymmetry (21/33), cutaneous capillary malformations (naevus flammeus 28/33, cutis marmorata 17/33). Intellectual disability was present in 15 patients. Among the MRI images reviewed, the neuroimaging findings were megalencephaly (20/21), thickening of corpus callosum (16/21), Chiari malformation (12/21), ventriculomegaly/hydrocephaly (10/21), cerebral asymmetry (6/21) and polymicrogyria (2/21). This study confirms the main known clinical features that defines MCAP syndrome. Taking into account the phenotypic heterogeneity in MCAP patients, in the context of emerging clinical trials, we suggest that patients should be evaluated based on the main neurocognitive expression on each patient., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Introduction: Megalencephalic leukoencephalopathy with cysts is a leukodystrophy of genetic origin that produces an alteration in the water and ion homeostasis in the brain, generating vacuolar forms and chronic oedema in the white matter with progressive neurological deterioration. It should be suspected in infants who present progressive macrocephaly during the first year of life, motor retardation and characteristic findings in magnetic resonance brain scans., Case Report: We report the case of a girl who was followed up from the age of 9 months due to progressive macrocephaly and delayed psychomotor development and brain MRI findings consistent with megalencephalic leukoencephalopathy with cysts, and the appearance of epilepsy during its development. The usual genetic studies (new generation sequencing and array) were negative, but as the diagnostic criteria were met, a complementary messenger RNA and DNA study was conducted, which confirmed the presence of two pathogenic variants in MLC1., Conclusions: Megalencephalic leukoencephalopathy with cysts is a rare condition. Progressive macrocephaly in the first year of life, the absence of deterioration or slow deterioration, and the possibility of developing epilepsy, spasticity and ataxia are characteristic signs in its course. It is important for these patients to undergo an imaging test that shows findings that characterise this condition, which, together with the clinical features, makes it possible to differentiate it from other leukodystrophies and to establish a confirmatory diagnosis. Genetic studies can confirm the associated mutation that makes it possible to predict the clinicoradiological phenotype.

Background: Conventional MRI sequences are often affected in neuropediatric imaging by unavoidable movements. Therefore, children younger than 6 years usually have to be examined under sedation/anesthesia. A new real-time MRI technique with automatic slice advancement allows for motion-robust T2-weighted volume coverage of the whole brain within a few seconds in adults., Objective: To evaluate to which extent the new volume coverage method can be used to visualize cerebrospinal fluid and reduce the need for anesthesia in children., Materials and Methods: We assessed 30 children ages 6 years and younger with suspected or proven hydrocephalus, hygroma or macrocephalus using volume coverage sequences with 20 slices per second in three planes. If necessary, a parent was placed in the bore together with the child for calming and gentle immobilization. We compared visualization of cerebrospinal fluid spaces and course of the shunt catheter in volume coverage sequences vs. fast spin-echo sequences., Results: The clinical issue could be sufficiently assessed in all children with use of volume coverage sequences, whereas conventional fast spin-echo sequences performed moderately to poorly. Visualization of the tip of a shunt failed in 16% of volume coverage scans and 27% of turbo spin-echo scans. A subsequent examination under anesthesia was never necessary. None of the examinations had to be stopped prematurely., Conclusion: The motion-robust volume coverage sequences with T2-type contrast can be used to avoid sedation of children in the evaluation of cerebrospinal fluid spaces, even in the presence of vigorous motion. For other indications and contrasts, the technique must still be evaluated.

Megalencephaly-capillary malformation-polymicrogyria (MCAP) syndrome (OMIM #602501) is characterized by megalencephaly, midline capillary malformations, and cortical malformations. This genetic overgrowth syndrome is associated with mosaic gain-of-function pathogenic PIK3CA variants (OMIM #171834).

De novo pathogenic variants in the GATAD2B gene have been associated with a syndromic neurodevelopmental disorder (GAND) characterized by severe intellectual disability (ID), impaired speech, childhood hypotonia, and dysmorphic features. Since its first description in 2013, nine patients have been reported in case reports and a series of 50 patients was recently published, which is consistent with the relative frequency of GATAD2B pathogenic variants in public databases. We report the detailed phenotype of 19 patients from various ethnic backgrounds with confirmed pathogenic GATAD2B variants including intragenic deletions. All individuals presented developmental delay with a median age of 2.5 years for independent walking and of 3 years for first spoken words. GATAD2B variant carriers showed very little subsequent speech progress, two patients over 30 years of age remaining non-verbal. ID was mostly moderate to severe, with one profound and one mild case, which shows a wider spectrum of disease severity than previously reported. We confirm macrocephaly as a major feature in GAND (53%). Most common dysmorphic features included broad forehead, deeply set eyes, hypertelorism, wide nasal base, and pointed chin. Conversely, prenatal abnormalities, non-cerebral malformations, epilepsy, and autistic behavior were uncommon. Other features included feeding difficulties, behavioral abnormalities, and unspecific abnormalities on brain MRI. Improving our knowledge of the clinical phenotype is essential for correct interpretation of the molecular results and accurate patient management., (Copyright © 2020. Published by Elsevier Masson SAS.)

Objective: To examine the occurrence and outcomes of fetuses with wide subarachnoid space (WSS) without ventriculomegaly in pregnant women with fetal macrocephaly as a sole diagnosis. Study design: A retrospective study was performed, analyzing patients with fetal macrocephaly between the years 2008 and 2018. All these patients underwent MRI, in order to detect brain anomalies. In the absence of any other brain abnormality, they were evaluated for WSS and their offspring's database was followed for at least two years after birth. Results: Ten patients were found to be carrying fetuses with macrocephaly, nine of them were diagnosed with WSS without ventriculomegaly prior to delivery. Following at least two years of follow up, all patients did not present significant neurodevelopmental abnormalities, apart from one child that had a genetic mutation of 15q21.2-22.31 deletion with other anomalies that were not diagnosed prenatally. Conclusions: We present herein for the first time in the literature a cohort of patients with a prenatal diagnosis of WSS without ventriculomegaly in fetuses with macrocephaly. Our data show that, in the presence of normal anomaly scan and normal chromosomal study, there is a low chance for significant neurodevelopmental abnormalities in fetuses with WSS without ventriculomegaly.

Megalencephaly-polymicrogyria-polydactyly-hydrocephalus (MPPH) syndrome is a developmental brain disorder characterized by an enlarged brain size with bilateral perisylvian polymicrogyria and a variable degree of ventriculomegaly. MPPH syndrome is associated with oromotor dysfunction, epilepsy, intellectual disability and postaxial hexadactyly. The molecular diagnosis of this disorder is established by the identification of a pathogenic variant in either AKT3, CCND2 or PIK3R2. Previously reported AKT3 variants are associated with various brain abnormalities and may lead to megalencephaly. MPPH syndrome is usually due to germline pathogenic AKT3 variants. Somatic mosaic pathogenic variants associated with hemimegalencephaly, which is similar to MPPH, have also been observed. A Hungarian Roma family with two half-siblings, which present with intellectual disability, dysmorphic features, epilepsy, brain malformations, and megalencephaly was studied. Whole exome sequencing (WES) analysis was performed. WES analysis revealed a heterozygous c.1393C > T p.(Arg465Trp) pathogenic missense AKT3 variant in both affected half-siblings. The variant was verified via Sanger sequencing and was not present in the DNA sample from the healthy mother, which was derived from peripheral blood, suggesting maternal germline mosaicism. In conclusion, this is the first report in which maternal germline mosaicism of a rare pathogenic AKT3 variant leads to autosomal dominantly inherited MPPH syndrome., Competing Interests: Declaration of Competing Interest The authors declare that there are no conflicts of interest., (Copyright © 2020. Published by Elsevier Inc.)

RIN2 syndrome also known as MACS syndrome is a rare autosomal recessive connective tissue disorder caused by RIN2 mutations and is accompanied by following clinical features: macrocephaly, coarsening of facial features, downward slanting palpebral fissures, Puffy droopy eyelids, full everted lips, soft redundant skin especially in face, gum hypertrophy, irregular dentition, sparse scalp hair, skeletal problems, joint hypermobility and scoliosis. RIN2 gene encodes the RAS and RAB interactor 2 and biallelic mutations in this gene cause cell trafficking dysfunction. Here we reported the eleventh patient of RIN2 syndrome in a 4 yr-old boy, from Tehran, Iran as the youngest reported patient so far. Whole exome sequencing revealed a novel frameshift homozygous variant of NM&#95;001242581.1: c.2251dup; p.(Leu751Profs*9) in RIN2 gene. In addition to the previously reported symptoms for the RIN2 syndrome, white matter abnormalities in his brain MRI were noticed. Our findings expand the clinical spectrum of MACS syndrome due to mutation in RIN2 gene., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Defects of the glycosylphosphatidylinositol (GPI) biosynthesis pathway constitute an emerging subgroup of congenital disorders of glycosylation with heterogeneous phenotypes. A mutation in the promoter of PIGM, resulting in a syndrome with portal vein thrombosis and persistent absence seizures, was previously described in three patients. We now report four additional patients in two unrelated families, with further clinical, biochemical and molecular delineation of this unique entity. We also describe the first prenatal diagnosis of PIGM deficiency, allowing characterization of the natural history of the disease from birth. The patients described herein expand the phenotypic spectrum of PIGM deficiency to include macrocephaly and infantile-onset cerebrovascular thrombotic events. Finally, we offer insights regarding targeted treatment of this rare disorder with sodium phenylbutyrate., (Copyright © 2019. Published by Elsevier Inc.)

Background: Macrocephaly is frequently encountered in pediatrics and often leads to imaging. There are no recommendations from the American Academy of Pediatrics or the American College of Radiology providing imaging guidelines for macrocephaly. The goal of this study is to identify risk factors for pathologic macrocephaly and to aid the clinician in identifying patients that would benefit from imaging., Methods: We conducted a medical record review throughout a multistate health care system, Sanford Health, from January 1, 2012 to December 31, 2016. Patients with macrocephaly were identified by problem list in children aged less than 36 months. Data collection included basic demographics, imaging modality, developmental delay, prematurity, seizures, focal neurological symptoms, family history of macrocephaly, sedation used, and sedation complications., Results: A total of 169 patients were included in the analysis. Imaging modalities included 39 magnetic resonance imagings (23.1%), 47 cranial computed tomographies (27.8%), and 83 head ultrasounds (49.1%). Imaging results demonstrated 13 abnormal studies with five of those studies being abnormal with high clinical yield. Patients with abnormal studies were more likely to have developmental delay (P = 0.04) or neurological symptoms (P = 0.015). Positive family history of macrocephaly was predictive of normal imaging (P = 0.004). There were no sedation complications., Conclusions: Intracranial imaging does not appear to be necessary in children with no risk factors and or a positive family history of macrocephaly. Risk factors such as developmental delay or neurological symptoms could identify children at risk for imaging abnormalities that require further management., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Macrocephaly diminishes quality of life for children whose head size inhibits independent mobility and appropriate interaction with caregivers. Cranial reduction is a method of addressing these issues, historically with a high morbidity due most commonly to bleeding and shunt complications. The authors present a 9-year-old girl with holoprosencephaly and severe macrocephaly from progressive hydrocephalus who underwent cranial reduction via reverse distraction osteogenesis, a method to slowly reduce the skull volume. The patient underwent circumferential occipital temporoparietal frontal craniotomy with placement of 4 cranial distractors, followed approximately 1 month later by removal of the distractors and cranioplasty with resorbable fixation devices. The patient demonstrated significant postoperative improvement in head control and interaction in school activities. This is the oldest patient with macrocephaly treated with reverse distraction in the literature to date. The slow contraction of the cranial vault with limited bony surgery at the time of initial reduction provides an additional safety margin, and should be considered in older children presenting with profound macrocephaly.

Purpose: Mutations in SZT2 have been previously reported in several cases of early onset epilepsy and intellectual disability. In this study we investigate potential causal mutations in two male siblings affected by early onset epilepsy, intellectual disability and macrocephaly., Methods: We use family-based whole-exome sequencing to identify candidate variants., Results: We report the identification of two potential causal SZT2 mutations in compound heterozygous state. We observe considerable differences in the clinical phenotype severity of the two affected individuals. The cerebral MRI revealed no abnormalities in the older affected brother, while in the youngest one it revealed a right frontal polymicrogiria. Moreover, while good seizure control was achieved in the older affected individual the younger brother is affected by pharmacoresistant epilepsy, progressive spastic paraplegia, cortical myoclonus and a more severe intellectual disability. We also analyzed the relative location of the reported pathogenic mutations in the SZT2 protein., Conclusion: Variable phenotypic expressivity is observed for this condition, while the location and type of mutations in SZT2 also has a potential impact on epilepsy severity. These findings extend our knowledge of epileptogenic conditions related to SZT2 and mTOR signaling., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Nuclear Factor One X (NFIX) haploinsufficiency in humans results in Malan syndrome, a disorder characterized by overgrowth, macrocephaly and intellectual disability. Although clinical assessments have determined the underlying symptomology of Malan syndrome, the fundamental mechanisms contributing to the enlarged head circumference and intellectual disability in these patients remains undefined., Methods: Here, we used Nfix heterozygous mice as a model to investigate these aspects of Malan syndrome. Volumetric magnetic resonance imaging (MRI) was used to calculate the volumes of 20 brain sub regions. Diffusion tensor MRI was used to perform tractography-based analyses of the corpus callosum, hippocampal commissure, and anterior commissure, as well as structural connectome mapping of the whole brain. Immunohistochemistry examined the neocortical cellular populations. Two behavioral assays were performed, including the active place avoidance task to assess spatial navigation and learning and memory function, and the 3-chambered sociability task to examine social behaviour., Findings: Adult Nfix +/- mice exhibit significantly increased brain volume (megalencephaly) compared to wildtypes, with the cerebral cortex showing the highest increase. Moreover, all three forebrain commissures, in particular the anterior commissure, revealed significantly reduced fractional anisotropy, axial and radial diffusivity, and tract density intensity. Structural connectome analyses revealed aberrant connectivity between many crucial brain regions. Finally, Nfix +/- mice exhibit behavioral deficits that model intellectual disability., Interpretation: Collectively, these data provide a significant conceptual advance in our understanding of Malan syndrome by suggesting that megalencephaly underlies the enlarged head size of these patients, and that disrupted cortical connectivity may contribute to the intellectual disability these patients exhibit. FUND: Australian Research Council (ARC) Discovery Project Grants, ARC Fellowship, NYSTEM and Australian Postgraduate Fellowships., (Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.)

Objective: We present digynic triploidy in a fetus with semilobar holoprosencephaly (HPE)., Case Report: A 32-year-old, gravid 1, para 0, woman underwent prenatal ultrasound examination at 12 weeks of gestation, and the ultrasound showed relative macrocephaly, a small non-cystic placenta, and a fetus with absent nasal bone and semilobar HPE. The pregnancy was terminated subsequently, and a 50-g fetus was delivered with a relatively enlarged head and premaxillary agenesis. The placenta was small and non-cystic. Postnatal cytogenetic analysis of the umbilical cord revealed a karyotype of 69, XXX. Postnatal DNA marker analysis using quantitative fluorescent polymerase chain reaction assays and the polymorphic short tandem repeat markers for chromosome 18 and 20 on the placental tissues showed a diallelic pattern with a dosage of 1:2 (paternal allele to maternal allele ratio), indicating a maternal origin of the triploidy., Conclusion: Fetuses with digynic triploidy may present relative macrocephaly, semilobar HPE and a small placenta on prenatal ultrasound., (Copyright © 2018. Published by Elsevier B.V.)

Mutations in the STE20-related kinase adaptor α ( STRADA) gene have been reported to cause an autosomal recessive neurodevelopmental disorder characterized by infantile-onset epilepsy, developmental delay, and craniofacial dysmorphisms. To date, there have been 17 reported individuals diagnosed with STRADA mutations, 16 of which are from a single Old Order Mennonite cohort and share a deletion of exons 9-13. The remaining individual is of consanguineous Indian descent and has a homozygous single-base pair duplication. We report a novel STRADA gene deletion of exons 7-9 in 2 sisters from nonconsanguineous parents, as well as an improvement in seizure control in 1 sibling following treatment with sirolimus, an m-Tor inhibitor of potential benefit to patients with this genetic mutation.

Channelopathies are disorders caused by abnormal ion channel function in differentiated excitable tissues. We discovered a unique neurodevelopmental channelopathy resulting from pathogenic variants in SCN3A, a gene encoding the voltage-gated sodium channel Na V 1.3. Pathogenic Na V 1.3 channels showed altered biophysical properties including increased persistent current. Remarkably, affected individuals showed disrupted folding (polymicrogyria) of the perisylvian cortex of the brain but did not typically exhibit epilepsy; they presented with prominent speech and oral motor dysfunction, implicating SCN3A in prenatal development of human cortical language areas. The development of this disorder parallels SCN3A expression, which we observed to be highest early in fetal cortical development in progenitor cells of the outer subventricular zone and cortical plate neurons and decreased postnatally, when SCN1A (Na V 1.1) expression increased. Disrupted cerebral cortical folding and neuronal migration were recapitulated in ferrets expressing the mutant channel, underscoring the unexpected role of SCN3A in progenitor cells and migrating neurons., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Germline mutations of the PTEN gene are responsible for several PTEN hamartoma tumor syndromes. They are also implicated as a cause of macrocephaly and mild to severe developmental delay, regardless of the presence or absence of hamartomas in childhood. Nevertheless, because of limited information, the clinical features present during childhood in patients with a PTEN mutation are yet to be elucidated., Methods: PTEN mutations were investigated by multiplex targeted sequencing of genomic DNA from 33 children with increased head circumference (>+2 SD) and developmental delay. The clinical features of all the patients with a PTEN mutation were abstracted by dysmorphologists., Results: We have identified six children with a PTEN mutation. Clinical dissection of these six patients, in addition to patient reports in the literature, revealed distinctive facial features that included frontal bossing, dolichocephaly, horizontal eyebrows, and a depressed nasal bridge. Macrocephaly (+3.2 to +6.0 SD) was noticeable compared to their height (-0.8 to +2.1 SD), and the difference in the SD value of head circumference and height was more than 3 SD in all patients., Conclusion: The presence of distinctive facies, extreme macrocephaly with normal to mildly high stature, and developmental delay may be useful for identifying patients with a PTEN mutation in childhood. Early identification of patients with a PTEN mutation would help uncover the natural course of tumor development in this group of individuals who have a possible predisposition to cancer, and be important for the development of an optimal surveillance strategy., (Copyright © 2018 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.)

Macrocephaly is a relatively common clinical condition affecting up to 5% of the pediatric population. It is defined as an abnormally large head with an occipitofrontal circumference greater than 2 standard deviations above the mean for a given age and sex. Megalencephaly refers exclusively to brain overgrowth exceeding twice the standard deviation. Macrocephaly can be isolated and benign or may be the first indication of an underlying congenital, genetic, or acquired disorder, whereas megalencephaly is more often syndromic. Megalencephaly can be divided into 2 subtypes: metabolic and developmental, caused by genetic defects in cellular metabolism and alterations in signaling pathways, respectively. Neuroimaging plays an important role in the evaluation of macrocephaly, especially in the metabolic subtype which may not be overtly apparent clinically. This article outlines the diverse etiologies of macrocephaly, delineates their clinical and radiographic features, and suggests a clinicoradiological algorithm for evaluation.

Dysplastic megalencephaly, also known as bilateral hemimegalencephaly, is a rare cerebral malformation characterized by bilateral cerebral hemisphere overgrowth and extensive malformation of cortical development. Affected patients present clinically with intractable seizures, severe neurological impairment and global developmental delay. There is a small body of literature reporting megalencephaly's association with neonatal high-output cardiac failure and a lack of literature describing prenatal findings. We report a case of dysplastic megalencephaly presenting with progressive high-output cardiac failure during fetal life. Prenatal and postnatal imaging findings as well as neonatal course are described. A companion case with similar imaging findings will help illustrate the prenatal imaging characteristics of this association. Knowledge of this potential complication related to dysplastic megalencephaly may help guide parental counseling and obstetric management.

Early-onset epileptic encephalopathies (EOEEs) are a genetically heterogeneous collection of severe epilepsies often associated with psychomotor regression. Mutations in SZT2, a known seizure threshold regulator gene, are a newly identified cause of EOEE. We present an individual with EOEE, macrocephaly, and developmental regression with compound heterozygous mutations in SZT2 as identified by whole exome sequencing. Serial imaging characterized the novel finding of progressive loss of central myelination. This case expands our clinical understanding of the SZT2-phenotype and emphasizes the role of this gene in the diagnostic investigation for EOEE and leukoencephalopathies., (© 2018 Wiley Periodicals, Inc.)

Smith-Kingsmore syndrome (SKS) OMIM #616638, also known as MINDS syndrome (ORPHA 457485), is a rare autosomal dominant disorder reported so far in 23 patients. SKS is characterized by intellectual disability, macrocephaly/hemi/megalencephaly, and seizures. It is also associated with a pattern of facial dysmorphology and other non-neurological features. Germline or mosaic mutations of the mTOR gene have been detected in all patients. The mTOR gene is a key regulator of cell growth, cell proliferation, protein synthesis and synaptic plasticity, and the mTOR pathway (PI3K-AKT-mTOR) is highly regulated and critical for cell survival and apoptosis. Mutations in different genes in this pathway result in known rare diseases implicated in hemi/megalencephaly with epilepsy, as the tuberous sclerosis complex caused by mutations in TSC1 and TSC2, or the PIK3CA-related overgrowth spectrum (PROS). We here present 4 new cases of SKS, review all clinical and molecular aspects of this disorder, as well as some characteristics of the patients with only brain mTOR somatic mutations., (© 2017 The Authors. Clinical Genetics published by John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: The purpose of this article is to offer a systematic approach to the imaging of children with macrocephaly and to illustrate key neuroimaging features of common and rare but important disorders., Conclusion: Macrocephaly is a common clinical finding in children. Increased volume of one of the intracranial compartments can enlarge the head either prenatally or postnatally while the cranial sutures are open. Imaging plays a central role in establishing a diagnosis and guiding management.