Search results for "megalencephaly"
showing 10 items of 14 documents
Clinical and neuroimaging findings in 33 patients with MCAP syndrome: A survey to evaluate relevant endpoints for future clinical trials
2021
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 pat…
Expanding the phenotype of reciprocal 1q21.1 deletions and duplications: a case series
2017
Abstract Background Recurrent reciprocal 1q21.1 deletions and duplications have been associated with variable phenotypes. Phenotypic features described in association with 1q21.1 microdeletions include developmental delay, craniofacial dysmorphism and congenital anomalies. The 1q21.1 reciprocal duplication has been associated with macrocephaly or relative macrocephaly, frontal bossing, hypertelorism, developmental delay, intellectual disability and autism spectrum disorder. Methods Our study describes seven patients, who were referred to us for developmental delay/intellectual disability, dysmorphic features and, in some cases, congenital anomalies, in whom we identified 1q21.1 CNVs by arra…
Intestinal malrotation in a female newborn affected by Osteopathia Striata with Cranial Sclerosis due to a de novo heterozygous nonsense mutation of …
2022
Abstract Background Osteopathia Striata with Cranial Sclerosis (OS-CS), also known as Horan-Beighton Syndrome, is a rare genetic disease; about 90 cases have been reported to date. It is associated with mutations (heterozygous for female subjects and hemizygous for males) of the AMER1 gene, located at Xq11.2, and shows an X-linked pattern of transmission. Typical clinical manifestations include macrocephaly, characteristic facial features (frontal bossing, epicanthal folds, hypertelorism, depressed nasal bridge, orofacial cleft, prominent jaw), hearing loss and developmental delay. Males usually present a more severe phenotype than females and rarely survive. Diagnostic suspicion is based o…
NFIB Haploinsufficiency Is Associated with Intellectual Disability and Macrocephaly
2018
The nuclear factor I (NFI) family of transcription factors play an important role in normal development of multiple organs. Three NFI family members are highly expressed in the brain, and deletions or sequence variants in two of these, NFIA and NFIX, have been associated with intellectual disability (ID) and brain malformations. NFIB, however, has not previously been implicated in human disease. Here, we present a cohort of 18 individuals with mild ID and behavioral issues who are haploinsufficient for NFIB. Ten individuals harbored overlapping microdeletions of the chromosomal 9p23-p22.2 region, ranging in size from 225 kb to 4.3 Mb. Five additional subjects had point sequence variations c…
Prenatal head growth and child neuropsychological development at age 14 months
2014
We sought to assess the association between prenatal head growth and child neuropsychological development in the general population.We evaluated 2104 children at the age of 14 months from a population-based birth cohort in Spain. Head circumference (HC) was measured by ultrasound examinations at weeks 12, 20, and 34 of gestation and by a nurse at birth. Head growth was assessed using conditional SD scores between weeks 12-20 and 20-34. Trained psychologists assessed neuropsychological functioning using the Bayley Scales of Infant Development. Head size measurements at birth were transformed into a 3-category variable: microcephalic (10th percentile), normocephalic (≥10th and90th percentile)…
Megalencephaly Syndromes and Activating Mutations in the PI3K-AKT Pathway: MPPH and MCAP
2013
The megalencephaly‐polymicrogyria‐polydactyly‐hydrocephalus (MPPH) and megalencephaly‐capillary malformation (MCAP) syndromes are highly recognizable and partly overlapping disorders of brain overgrowth (megalencephaly). Both syndromes are characterized by congenital or early postnatal megalencephaly, with a high risk for progressive ventriculomegaly leading to hydrocephalus and cerebellar tonsillar ectopia leading to Chiari malformation, and cortical brain abnormalities, specifically polymicrogyria. MCAP is further characterized by distinct cutaneous capillary malformations, finger or toe syndactyly, postaxial polydactyly, variable connective tissue dysplasia and mild focal or segmental bo…
Microcephaly and macrocephaly. A study on anthropometric and clinical data from 308 subjects
2019
Head circumference is the auxological parameter that most correlates with developmental anomalies in childhood. Head circumference (HC) two standard deviations (SD) below or above the mean defines microcephaly and macrocephaly, respectively. The aim of this retrospective study was to explore anthropometric parameters and clinical characteristics among subjects with abnormalities in HC who had been referred for developmental assessment. One hundred and sixty four subjects with microcephaly and 144 subjects with macrocephaly were enrolled from birth to 18 months of age. Head circumference at birth and the association with variables related to maternal health status, gestational age, growth pa…
De novo CCND2 mutations leading to stabilization of cyclin D2 cause megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome
2014
Activating mutations in genes encoding phosphatidylinositol 3-kinase (PI3K)-AKT pathway components cause megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome (MPPH, OMIM 603387)(1-3). Here we report that individuals with MPPH lacking upstream PI3K-AKT pathway mutations carry de novo mutations in CCND2 (encoding cyclin D2) that are clustered around a residue that can be phosphorylated by glycogen synthase kinase 313 (GSK-3 beta)(4). Mutant CCND2 was resistant to proteasomal degradation in vitro compared to wild-type CCND2. The PI3K-AKT pathway modulates GSK-3 beta activity(4), and cells from individuals with PIK3CA, PIK3R2 or AKT3 mutations showed similar CCND2 accumulation. CCND…
A clinical review on megalencephaly: A large brain as a possible sign of cerebral impairment
2017
Megalencephaly and macrocephaly present with a head circumference measurement 2 standard deviations above the age-related mean. However, even if pathologic events resulting in both megalencephaly and macrocephaly may coexist, a distinction between these two entities is appropriate, as they represent clinical expression of different disorders with a different approach in clinical work-up, overall prognosis, and treatment. Megalencephaly defines an increased growth of cerebral structures related to dysfunctional anomalies during the various steps of brain development in the neuronal proliferation and/or migration phases or as a consequence of postnatal abnormal events. The disorders associate…
PI3K/AKT pathway mutations cause a spectrum of brain malformations from megalencephaly to focal cortical dysplasia
2015
Malformations of cortical development containing dysplastic neuronal and glial elements, including hemimegalencephaly and focal cortical dysplasia, are common causes of intractable paediatric epilepsy. In this study we performed multiplex targeted sequencing of 10 genes in the PI3K/AKT pathway on brain tissue from 33 children who underwent surgical resection of dysplastic cortex for the treatment of intractable epilepsy. Sequencing results were correlated with clinical, imaging, pathological and immunohistological phenotypes. We identified mosaic activating mutations in PIK3CA and AKT3 in this cohort, including cancer-associated hotspot PIK3CA mutations in dysplastic megalencephaly, hemimeg…