Unveiling Secondary Mutations in Blended Phenotypes: Dual ERCC4 and OTOA Pathogenic Variants Through WES Analysis.

This study describes two siblings from consanguineous parents who exhibit intellectual disability, microcephaly, photosensitivity, bilateral sensorineural hearing loss, numerous freckles, and other clinical features that suggest a potential disruption of the nucleotide excision repair (NER) pathway. Whole exome sequencing (WES) identified a novel homozygous missense variant in the gene, which was predicted to be pathogenic. However, a subsequent peculiar audiometric finding prompted further investigation, revealing a homozygous deletion in the gene linked to neurosensorial hearing loss.

Assortative mating and parental genetic relatedness contribute to the pathogenicity of variably expressive variants.

We examined more than 97,000 families from four neurodevelopmental disease cohorts and the UK Biobank to identify phenotypic and genetic patterns in parents contributing to neurodevelopmental disease risk in children. We identified within- and cross-disorder correlations between six phenotypes in parents and children, such as obsessive-compulsive disorder (R = 0.32-0.

Assortative mating and parental genetic relatedness drive the pathogenicity of variably expressive variants.

We examined more than 38,000 spouse pairs from four neurodevelopmental disease cohorts and the UK Biobank to identify phenotypic and genetic patterns in parents associated with neurodevelopmental disease risk in children. We identified correlations between six phenotypes in parents and children, including correlations of clinical diagnoses such as obsessive-compulsive disorder (R=0.31-0.

Trait - driven analysis of the 2p15p16.1 microdeletion syndrome suggests a complex pattern of interactions between candidate genes.

Background: Individuals with the 2p15p16.1 microdeletion syndrome share a complex phenotype including neurodevelopmental delay, brain malformations, microcephaly, and autistic behavior. The analysis of the shortest region of overlap (SRO) between deletions in ~ 40 patients has led to the identification of two critical regions and four strongly candidate genes (BCL11A, REL, USP34 and XPO1).

Heterozygous Deletion of Long Noncoding RNA AK127244 Is a Susceptibility Factor for Neurodevelopmental Delay.

Neurodevelopmental syndromes due to copy number variation are well-known clinical entities. While the numerical variation of gene-harboring regions has been widely investigated at both molecular and clinical levels, much less is understood about unbalanced expression of long noncoding RNAs. Few studies have been performed on the clinical consequences of such unbalanced expression.

Phenotypic Spectrum of Haploinsufficiency: Two Additional Cases and Review of the Literature.

The (nuclear factor I/A) gene encodes for a transcription factor belonging to the nuclear factor I family and has key roles in various embryonic differentiation pathways. In humans, is the major contributor to the phenotypic traits of "Chromosome 1p32p31 deletion syndrome". We report on two new cases with deletions involving without any other pathogenic protein-coding gene alterations.

Dyslexia and Attention Deficit Hyperactivity Disorder Associated to a De Novo 1p34.3 Microdeletion.

The authors report on a boy with dyslexia and attention deficit hyperactivity disorder. A protocol of standardized tests assessed the neuroadaptive profile, allowing deep neuropsychiatric phenotyping. In addition to the diagnosis of dyslexia and attention deficit hyperactivity disorder, such methodology led to endeavor cognitive, adaptive, and academic skills.

8p23.2-pter Microdeletions: Seven New Cases Narrowing the Candidate Region and Review of the Literature.

To date only five patients with 8p23.2-pter microdeletions manifesting a mild-to-moderate cognitive impairment and/or developmental delay, dysmorphisms and neurobehavioral issues were reported. The smallest microdeletion described by Wu in 2010 suggested a critical region (CR) of 2.

Rare deleterious mutations of HNRNP genes result in shared neurodevelopmental disorders.

Background: With the increasing number of genomic sequencing studies, hundreds of genes have been implicated in neurodevelopmental disorders (NDDs). The rate of gene discovery far outpaces our understanding of genotype-phenotype correlations, with clinical characterization remaining a bottleneck for understanding NDDs. Most disease-associated Mendelian genes are members of gene families, and we hypothesize that those with related molecular function share clinical presentations.

Disruptive variants of associate with autism and interfere with neuronal development and synaptic transmission.

RNA binding proteins are key players in posttranscriptional regulation and have been implicated in neurodevelopmental and neuropsychiatric disorders. Here, we report a significant burden of heterozygous, likely gene-disrupting variants in (encoding a highly constrained RNA binding protein) among patients with autism and related neurodevelopmental disabilities. Analysis of 17 patients identifies common phenotypes including autism, intellectual disability, language and motor delay, seizures, macrocephaly, and variable ocular abnormalities.

Biallelic intragenic duplication in ADGRB3 (BAI3) gene associated with intellectual disability, cerebellar atrophy, and behavioral disorder.

In recent years, chromosomal microarray analysis has permitted the discovery of rearrangements underlying several neurodevelopmental disorders and still represents the first diagnostic test for unexplained neurodevelopmental disabilities. Here we report a family of consanguineous parents showing psychiatric disorders and their two sons both affected by intellectual disability, ataxia, and behavioral disorder. SNP/CGH array analysis in this family demonstrated in both siblings a biallelic duplication inherited from the heterozygous parents, disrupting the ADGRB3 gene.

Mutations in ACTL6B, coding for a subunit of the neuron-specific chromatin remodeling complex nBAF, cause early onset severe developmental and epileptic encephalopathy with brain hypomyelination and cerebellar atrophy.

Developmental and epileptic encephalopathies (DEEs) are genetically heterogenous conditions, often characterized by early onset, EEG interictal epileptiform abnormalities, polymorphous and drug-resistant seizures, and neurodevelopmental impairments. In this study, we investigated the genetic defects in two siblings who presented with severe DEE, microcephaly, spastic tetraplegia, diffuse brain hypomyelination, cerebellar atrophy, short stature, and kyphoscoliosis. Whole exome next-generation sequencing (WES) identified in both siblings a homozygous non-sense variant in the ACTL6B gene (NM_016188:c.

Rare variants in the genetic background modulate cognitive and developmental phenotypes in individuals carrying disease-associated variants.

Purpose: To assess the contribution of rare variants in the genetic background toward variability of neurodevelopmental phenotypes in individuals with rare copy-number variants (CNVs) and gene-disruptive variants.

Methods: We analyzed quantitative clinical information, exome sequencing, and microarray data from 757 probands and 233 parents and siblings who carry disease-associated variants.

Results: The number of rare likely deleterious variants in functionally intolerant genes ("other hits") correlated with expression of neurodevelopmental phenotypes in probands with 16p12.

Definition of minimal duplicated region encompassing the XIAP and STAG2 genes in the Xq25 microduplication syndrome.

Typical Xq25 duplications are large and associated with heterogeneous phenotypes. Recently, small duplications involving this genomic region and encompassing the GRIA3 and STAG2 genes have been reported. These Xq25 microduplications are associated with a recognizable syndrome including intellectual disability and distinctive facial appearance.

Identification of pathogenic gene variants in small families with intellectually disabled siblings by exome sequencing.

Background: Intellectual disability (ID) is a common neurodevelopmental disorder affecting 1-3% of the general population. Mutations in more than 10% of all human genes are considered to be involved in this disorder, although the majority of these genes are still unknown.

Objectives: We investigated 19 small non-consanguineous families with two to five affected siblings in order to identify pathogenic gene variants in known, novel and potential ID candidate genes.

Brief report: peculiar evolution of autistic behaviors in two unrelated children with brachidactyly-mental retardation syndrome.

Brachidactyly-Mental Retardation (BDMR) Syndrome (MIM 600430) is associated with terminal deletions at chromosome 2q37 and a limited number of studies also reported an association between 2q37 → qter deletion and autism. Herein we describe two cases of autism in unrelated children with BDMR Syndrome, showing physical, cognitive, behavioral, and disease natural history homologies, with a very prominent social impairment in the first 4 years of life. At follow-up evaluations, spanning a 5-years period, both children experienced a progressive reduction of the autistic symptoms, besides retaining compromised cognitive ability.

A de novo 8q22.2-24.3 duplication in a patient with mild phenotype.

We report a new case of 8q interstitial duplication in a patient with dysmorphic features, umbilical hernia, cryptorchidism, short stature, congenital heart defect and mild mental retardation (MR). Chromosome analysis with high resolution QFQ bands showed 46,XY, 8q+, which was interpreted as a partial duplication of the distal long arm of chromosome 8 (q22 → qter). This chromosomal aberration was further characterized using fluorescence in situ hybridization (FISH) analyses with multiple DNA probes and array-CGH (Comparative Genomic Hybridization) experiment which demonstrated a de novo direct duplication (8)(q22.

Molecular mechanisms generating and stabilizing terminal 22q13 deletions in 44 subjects with Phelan/McDermid syndrome.

In this study, we used deletions at 22q13, which represent a substantial source of human pathology (Phelan/McDermid syndrome), as a model for investigating the molecular mechanisms of terminal deletions that are currently poorly understood. We characterized at the molecular level the genomic rearrangement in 44 unrelated patients with 22q13 monosomy resulting from simple terminal deletions (72%), ring chromosomes (14%), and unbalanced translocations (7%). We also discovered interstitial deletions between 17-74 kb in 9% of the patients.

Bilateral periventricular nodular heterotopia and lissencephaly in an infant with unbalanced t(12;17)(q24.31; p13.3) translocation.

Periventricular nodular heterotopia and Miller-Dieker syndrome are two different disorders of brain development. Miller-Dieker syndrome exhibits classical lissencephaly and is related to defects in the lissencephaly gene (LIS1). Periventricular nodular heterotopia is characterized by aggregates of grey matter adjacent to the lateral ventricle and is mainly linked to mutations in the Filamin A (FLNA) gene.

Partial monosomy Xq(Xq23 --> qter) and trisomy 4p(4p15.33 --> pter) in a woman with intractable focal epilepsy, borderline intellectual functioning, and dysmorphic features.

Studies of epilepsy associated with chromosomal abnormalities may provide information about clinical and EEG phenotypes and possibly to identify new epilepsy genes. We describe a female patient with intractable focal epilepsy, borderline intellectual functioning, and facial dysmorphisms, in whom genetic study (i.e.

1.5 Mb de novo 22q11.21 microduplication in a patient with cognitive deficits and dysmorphic facial features.

The 22q11.2 microduplication syndrome is caused by non-allelic homologous recombination mediated by misalignments of low copy repeats located in the region deleted in the DiGeorge syndrome (DGS)/velocardiofacial syndrome (VCFS). The variable phenotype of such condition, consisting in a combination of dysmorphic facial features, cognitive deficits, velopharyngeal insufficiency, congenital heart defects and immunologic derangement, is caused usually in 90% of cases by a 3 Mb deletion or in a minority of cases (7%) by a 1.