Thousand and one amino-acid kinase 1 (TAOK1) encodes the MAP3K protein kinase TAO1, which has recently been displayed to be essential for neuronal maturation and cortical differentiation during early ...brain development. Heterozygous variants in TAOK1 have been reported in children with neurodevelopmental disorders, with or without macrocephaly, hypotonia and mild dysmorphic traits. Literature reports lack evidence of neuronal migration disorders in TAOK1 patients, although studies in animal models suggest this possibility.
We provide a clinical description of a child with a neurodevelopmental disorder due to a novel TAOK1 truncating variant, whose brain magnetic resonance imaging displays periventricular nodular heterotopia.
To our knowledge, this is the first report of a neuronal migration disorder in a patient with a TAOK1-related neurodevelopmental disorder, thus supporting the hypothesized pathogenic mechanisms of TAOK1 defects.
Raynaud-Claes syndrome is a very rare X-linked condition, characterized by intellectual disability, impaired language development, brain abnormalities, facial dysmorphisms and drug-resistant ...epilepsy. It is caused by loss-of-function variants in the CLCN4 gene, which encodes the 2Cl−/H + exchanger ClC-4, prominently expressed in the hippocampus and cerebellum. Different genotypic variants have been described, each exhibiting specific phenotypic characteristics. The loss-of-function variant p.Gly544Arg in the CLCN4 gene has been described in only two male probands, but there are no reports on phenotypic characterization in females.
We present a 30-year-old Italian woman with early-onset drug-resistant epilepsy, developmental and epileptic encephalopathy, developmental delay, absence of verbal language development, behavioral impairment with autistic features, and clusters of seizures during catamenial periods. The interictal EEG showed slight inconstant slowing of the background rhythm, with abnormal frontal predominant mu like rhythm and generalized spike and polyspike wave discharges, which increased in frequency during drowsiness. A brain MRI showed slight cranio-encephalic asymmetry and a smaller size of the left hippocampus. The whole exome sequencing (WES) revealed a de novo heterozygous c.1630G > A variant in the CLCN4 gene, resulting in the amino acid substitution p.Gly544Arg (rs587777161), consistent with Raynaud-Claes syndrome.
Our patient is the first case of a de novo p.Gly544Arg variant of the CLCN4 gene in a female proband, confirming that female patients with Raynaud-Claes syndrome can be as severely affected as the male counterparts. Our case expands the phenotypic characterization of different genotypic CLCN4 variants, which can become crucial in the future for early diagnosis if targeted therapy becomes available.
The genetic causes of epilepsies and developmental and epileptic encephalopathies (DEE) with onset in early childhood are increasingly recognized. Their outcomes vary from benign to severe ...disability. In this paper, we wished to retrospectively review the clinical, genetic, EEG, neuroimaging, and outcome data of patients experiencing the onset of epilepsy in the first three years of life, diagnosed and followed up in four Italian epilepsy centres (Epilepsy Centre of San Paolo University Hospital in Milan, Child Neurology and Psychiatry Unit of AUSL-IRCCS di Reggio Emilia, Pediatric Neurology Unit of Vittore Buzzi Children's Hospital, Milan, and Child Neurology and Psychiatry Unit, IRCCS Mondino Foundation, Pavia). We included 168 patients (104 with monogenic conditions, 45 with copy number variations (CNVs) or chromosomal abnormalities, and 19 with variants of unknown significance), who had been followed up for a mean of 14.75 years. We found a high occurrence of generalized seizures at onset, drug resistance, abnormal neurological examination, global developmental delay and intellectual disability, and behavioural and psychiatric comorbidities. We also documented differing presentations between monogenic issues versus CNVs and chromosomal conditions, as well as atypical/rare phenotypes. Genetic early-childhood-onset epilepsies and DEE show a very wide phenotypic and genotypic spectrum, with a high risk of complex neurological and neuropsychiatric phenotypes.
We report a 7-year-old boy born with epidermal nevi (EN) arranged according to Blaschko’s lines involving the face and head, right upper limb, chest, and left lower limb, who developed a left ...paratesticular embryonal rhabdomyosarcoma at 18 months of age. Parallel sequencing identified a gain-of-function variant (c.37G>C, p.Gly13Arg) of
HRAS
in both epidermal nevus and tumor but not in leukocytes or buccal mucosal epithelial cells, indicating its postzygotic origin. The variant accounted for 33% and 92% of the total reads in the nevus and tumor DNA specimens, respectively, supporting additional somatic hits in the latter. DNA methylation (DNAm) profiling of the tumor documented a signature consistent with embryonal rhabdomyosarcoma and CNV array analysis inferred from the DNAm arrays and subsequent MLPA analysis demonstrated copy number gains of the entire paternal chromosome 11 carrying the mutated
HRAS
allele, likely as the result of paternal unidisomy followed by subsequent gain(s) of the paternal chromosome in the tumor. Other structural rearrangements were observed in the tumours, while no additional pathogenic variants affecting genes with role in the RAS-MAPK and PI3K-AKT-MTOR pathways were identified. Our findings provide further evidence of the contribution of “gene dosage” to the multistep process driving cell transformation associated with hyperactive HRAS function.
Alazami syndrome (MIM#615071) is a rare developmental disorder caused by biallelic variants in the LARP7 gene. Hallmark features include short stature, global developmental delay, and distinctive ...facial features. To date, 23 patients from 11 families have been reported in the literature. Here we describe a 19-year-old man who, in association with the typical features of Alazami syndrome, was diagnosed at the age of 14 years with papillary thyroid carcinoma, harboring the somatic BRAF V600E mutation. Whole exome sequencing revealed two novel LARP7 variants in compound heterozygosity, whereas only common variants were detected in genes associated with familial nonmedullary thyroid cancer (MIM#188550). LARP7 acts as a tumor suppressor in breast and gastric cancer, and possibly, according to recent studies, in thyroid tumors. Since thyroid cancer is rare among children and adolescents, we hypothesize that the LARP7 variants identified in our patient are responsible for both Alazami syndrome and tumor susceptibility. We also provide an overview of the clinical findings in all Alazami syndrome patients reported to date and discuss the possible pathogenetic mechanism that may underlie this condition, including the role of LARP7 in tumor susceptibility.
Microcephaly primary hereditary (MCPH) is a congenital disease characterized by nonsyndromic reduction in brain size due to impaired neurogenesis, often associated with a variable degree of ...intellectual disability (ID). The genetic etiology of MCPH is heterogeneous and comprises more than 20 loci, nearly all following a recessive inheritance pattern. The first causative gene identified,
or
, encodes a centrosomal protein that modulates chromosome condensation and cell cycle progression. It is also involved in DNA damage response and telomere maintenance in the nucleus. Despite numerous studies on
function, MCPH1-affected individuals are rare and the available clinical reports are not sufficient to define the natural history of the disease. Here, we present a novel patient with congenital microcephaly, ID, language delay, short stature, and other minor features such as strabismus. magnetic resonance imaging revealed ventriculomegaly, simplified gyral pattern in the frontal lobes, and a neuronal migration defect. Genetic testing detected a homozygous deletion of exons 1-8 of
. We compare the patients' characteristics with a list of features from MCPH1 cases described in the literature, in an effort to provide additional clues for a comprehensive definition of disease presentation and evolution.
We aimed to report on previously unappreciated clinical features associated with
-related intellectual disability (ID) syndrome, a rare neurodevelopmental disorder characterized by global ...developmental delay, intellectual disability, and language delay, with or without autistic features.
We performed whole-exome sequencing (WES) to molecularly characterize an individual presenting with ID, epilepsy, autism spectrum disorder, behavioral problems, and facial dysmorphisms as major features.
WES allowed us to identify a previously unreported
splice site variant, c.1429-1G>T (NM_032682.6), in the
gene (OMIM
605515) as the causative event underlying the phenotype. Clinical reassessment of the patient and revision of the literature allowed us to refine the phenotype associated with
haploinsufficiency, including hyperkinetic movement disorder and flat angiomas as associated features. Interestingly, the patient also has an asymmetric face and choanal atresia and a novel
variant of the
gene.
We suggest that
-related ID syndrome may also predispose to the development of hyperkinetic movement disorders and flat angiomas. These features could therefore require specific management of this condition.
In 1990, Gorlin et al. described four types of craniofacial duplications: (1) single mouth with duplication of the maxillary arch; (2) supernumerary mouth laterally placed with rudimentary segments; ...(3) single mouth with replication of the mandibular segments; and (4) true facial duplication, namely diprosopus. We describe a newborn born with wide-spaced eyes, a very broad nose, and two separate mouths. Workup revealed the absence of the corpus callosum and the presence of a brain midline lipoma, wide sutures, and a Chiari I malformation with cerebellar herniation. We conducted a systematic review of the literature and compared all the cases described as diprosopus. In 96% of these, the central nervous system is affected, with anencephaly being the most commonly associated abnormality. Other associated anomalies include cardiac malformations (86%), cleft palate (63%), diaphragmatic hernia (13%), and disorder of sex development (DSD) (13%). Although the facial features are those that first strike the eye, the almost obligate presence of cerebral malformations suggests a disruptive event in the cephalic pole of the forming embryo. No major monogenic contribution has been recognized today for this type of malformation.
Split Hand-Foot Malformation (SHFM) is a congenital limb defect characterized by a median cleft of the hands and/or feet due to the absence/hypoplasia of the central rays. It may occur as part of a ...syndromic condition or as an isolated malformation. The most common of the six genetic loci identified for this condition is correlated to SHFM1 and maps in the 7q21q22 region. SHFM1 is characterized by autosomal dominant transmission, incomplete penetrance and variable expressivity. Associated features often include hearing loss, intellectual disability/developmental delay and craniofacial abnormalities. Disruption of the DLX5/DLX6 genes, mapping within the SHFM1 locus, is now known to be responsible for the phenotype. Through SNP array, we analyzed a patient affected by SHFM1 associated with deafness and an abnormality of the inner ear (incomplete partition type I); we identified a deletion in 7q21, not involving the DLX5/6 genes, but including exons 15 and 17 of DYNC1I1, known to act as exonic enhancers (eExons) of the DLX5/6 genes. We further demonstrated the role of DYNC1I1 eExons in regulating DLX5/6 expression by means of showing a reduced expression of the DLX5/6 genes through RT-PCR in a patient-derived lymphoblastoid cell line. Furthermore, our data and a review of published cases do not support the hypothesis that DLX5/6 are imprinted in humans. This work is an example of how the disruption of regulatory elements can be responsible for congenital malformations.
Osteocraniostenosis (OCS, OMIM #602361) is a severe, usually lethal condition characterized by gracile bones with thin diaphyses, a cloverleaf-shaped skull and splenic hypo/aplasia. The condition is ...caused by heterozygous mutations in the
gene and is allelic to the non-lethal, dominant disorder Kenny-Caffey syndrome (KCS, OMIM #127000). Here we report two new cases of OCS, including one with a detailed pathological examination. We review the main diagnostic signs of OCS both before and after birth based on our observations and on the literature. We then review the current knowledge on the mutational spectrum of
associated with either OCS or KCS, including three novel variants, both from one of the OCS fetuses described here, and from further cases diagnosed at our centers. This report refines the previous knowledge on OCS and expands the mutational spectrum that results in either OCS or KCS.
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