Search

The impact of common and rare variants in COVID-19 host genetics has been widely studied. In particular, in Fallerini et al. (Human genetics, 2022, 141, 147-173), common and rare variants were used to define an interpretable machine learning model for predicting COVID-19 severity. First, variants were converted into sets of Boolean features, depending on the absence or the presence of variants in each gene. An ensemble of LASSO logistic regression models was used to identify the most informative Boolean features with respect to the genetic bases of severity. After that, the Boolean features, selected by these logistic models, were combined into an Integrated PolyGenic Score (IPGS), which offers a very simple description of the contribution of host genetics in COVID-19 severity. IPGS leads to an accuracy of 55%-60% on different cohorts, and, after a logistic regression with both IPGS and age as inputs, it leads to an accuracy of 75%. The goal of this paper is to improve the previous results, using not only the most informative Boolean features with respect to the genetic bases of severity but also the information on host organs involved in the disease. In this study, we generalize the IPGS adding a statistical weight for each organ, through the transformation of Boolean features into "Boolean quantum features," inspired by quantum mechanics. The organ coefficients were set via the application of the genetic algorithm PyGAD, and, after that, we defined two new integrated polygenic scores (IPGS¹ph and IPGS²ph). By applying a logistic regression with both IPGS, (IPGS²ph (or indifferently IPGS¹ph) and age as inputs, we reached an accuracy of 84%-86%, thus improving the results previously shown in Fallerini et al. (Human genetics, 2022, 141, 147-173) by a factor of 10%. [ABSTRACT FROM AUTHOR]

Familial hematuria is a clinical sign of a genetically heterogeneous group of conditions, accompanied by broad inter- and intrafamilial variable expressivity. The most frequent condition is caused by pathogenic (or likely pathogenic) variants in the collagen-IV genes, COL4A3/A4/A5. Pathogenic variants in COL4A5 are responsible for the severe X-linked glomerulopathy, Alport syndrome (AS), while homozygous or compound heterozygous variants in the COL4A3 or the COL4A4 gene cause autosomal recessive AS. AS usually leads to progressive kidney failure before the age of 40-years when left untreated. People who inherit heterozygous COL4A3/A4 variants are at-risk of a slowly progressive form of the disease, starting with microscopic hematuria in early childhood, developing Alport spectrum nephropathy. Sometimes, they are diagnosed with benign familial hematuria, and sometimes with autosomal dominant AS. At diagnosis, they often show thin basement membrane nephropathy, reflecting the uniform thin glomerular basement membrane lesion, inherited as an autosomal dominant condition. On a long follow-up, most patients will retain normal or mildly affected kidney function, while a substantial proportion will develop chronic kidney disease (CKD), even kidney failure at an average age of 55-years. A question that remains unanswered is how to distinguish those patients with AS or with heterozygous COL4A3/A4 variants who will manifest a more aggressive kidney function decline, requiring prompt medical intervention. The hypothesis that a subgroup of patients coinherit additional genetic modifiers that exacerbate their clinical course has been investigated by several researchers. Here, we review all publications that describe the potential role of candidate genetic modifiers in patients and include a summary of studies in AS mouse models. [ABSTRACT FROM AUTHOR]

Pathogenic loss-of-function variants in the IQ motif and SEC7 domain containing protein 2 (IQSEC2) gene cause intellectual disability with Rett syndrome (RTT)-like features. The aim of this study was to obtain systematic information on the natural history and extra-central nervous system (CNS) manifestations for the Italian IQSEC2 population (>90%) by using structured family interviews and semi-quantitative questionnaires. IQSEC2 encephalopathy prevalence estimate was 7.0 to 7.9 × 10−7. Criteria for typical RTT were met in 42.1% of the cases, although psychomotor regression was occasionally evidenced. Genetic diagnosis was occasionally achieved in infancy despite a clinical onset before the first 24 months of life. High severity in both the CNS and extra-CNS manifestations for the IQSEC2 patients was documented and related to a consistently adverse quality of life. Neurodevelopmental delay was diagnosed before the onset of epilepsy by 1.8 to 2.4 years. An earlier age at menarche in IQSEC2 female patients was reported. Sleep disturbance was highly prevalent (60 to 77.8%), with mandatory co-sleeping behavior (50% of the female patients) being related to de novo variant origin, younger age, taller height with underweight, better social interaction, and lower life quality impact for the family and friends area. In conclusion, the IQSEC2 encephalopathy is a rare and likely underdiagnosed developmental encephalopathy leading to an adverse life quality impact. [ABSTRACT FROM AUTHOR]

We report a case of Klippel Trenaunay Syndrome that was monitored both clinically and molecularly over a period of 9 years. A somatic mosaic mutation of PIK3CA (p(E545G)) was identified using both cfDNA NGS liquid biopsy and tissue biopsy. At the age of 56, due to intervening clonal mutations in PIK3CA background, she developed a squamous cell carcinoma in the right affected leg which was treated surgically. Nine years later, lung bilateral adenocarcinoma arose on PIK3CA mutated tissues supported by different clonal mutations. One year later, the patient died from metastases led by a new FGFR3 clone unresponsive to standard-of-care, immunotherapy-based. Our results highlight the presence of a molecular hallmark underlying neoplastic transformation that occurs upon an angiodysplastic process and support the view that PIK3CA mutated tissues must be treated as precancerous lesions. Importantly, they remark the effectiveness of combining cfDNA NGS liquid and tissue biopsies to monitor disease evolution as well as to identify aggressive clones targetable by tailored therapy, which is more efficient than conventional protocols. [ABSTRACT FROM AUTHOR]

The membrane-bound O-acyltransferase domain-containing 7 (MBOAT7) protein is an acyltransferase catalyzing arachidonic acid incorporation into lysophosphatidylinositol. Patients with rare, biallelic loss-of-function variants of the MBOAT7 gene display intellectual disability with neurodevelopmental defects. The rs641738 inherited variant associated with reduced hepatic MBOAT7 expression has been linked to steatotic liver disease susceptibility. However, the impact of biallelic loss-of-function MBOAT7 variants on liver disease is not known. We report on a 2-year-old girl with MBOAT7-related intellectual disability and steatotic liver disease, confirming that MBOAT7 loss-of-function predisposes to liver disease. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic was complicated by the spread of false information leading to what became widely called an "infodemic". The present opinion paper was written by an ad hoc international team united under the European Union of Medical Specialists (UEMS) umbrella and reflects the organizations' effort to contribute to the resolution of these issues, by highlighting and reflecting on them and by suggesting the medical community's necessary activities resulting in the formulation of effective future communication strategies. The importance of physicians' and other health workers' role and mission as educators and leaders in communities in critical situations should be reassessed and upgraded. We need to equip future doctors with strong and sustainable leadership and communication skills through relevant undergraduate and postgraduate education programs, in order that compliance with preventive medical advice is increased. To avoid possible politically and otherwise biased communication in health crises of the future, European nations should establish independent advisory bodies providing evidence-based advice and participate in communication campaigns. Medical and other health professional organizations should build organizational and personal capacities of their members to enable them to reliably inform and adequately educate governments, populations, civic society, employers' and employees' organizations, schools and universities, and other stakeholders. [ABSTRACT FROM AUTHOR]

The bacterial product CNF1, through its action on the Rho GTPases, is emerging as a modulator of crucial signalling pathways involved in selected neurological diseases characterized by mitochondrial dysfunctions. Mitochondrial impairment has been hypothesized to have a key role in paramount mechanisms underlying Rett syndrome (RTT), a severe neurologic rare disorder. CNF1 has been already reported to have beneficial effects in mouse models of RTT. Using human RTT fibroblasts from four patients carrying different mutations, as a reliable disease‐in‐a‐dish model, we explored the cellular and molecular mechanisms, which can underlie the CNF1‐induced amelioration of RTT deficits. We found that CNF1 treatment modulates the Rho GTPases activity of RTT fibroblasts and induces a considerable re‐organization of the actin cytoskeleton, mainly in stress fibres. Mitochondria of RTT fibroblasts show a hyperfused morphology and CNF1 decreases the mitochondrial mass leaving substantially unaltered the mitochondrial dynamic. From a functional perspective, CNF1 induces mitochondrial membrane potential depolarization and activation of AKT in RTT fibroblasts. Given that mitochondrial quality control is altered in RTT, our results are suggestive of a reactivation of the damaged mitochondria removal via mitophagy restoration. These effects can be at the basis of the beneficial effects of CNF1 in RTT. [ABSTRACT FROM AUTHOR]

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been responsible for a devastating pandemic since March 2020. Toll-like receptors (TLRs), crucial components in the initiation of innate immune responses to different pathogens, trigger the downstream production of pro-inflammatory cytokines, interferons, and other mediators. It has been demonstrated that they contribute to the dysregulated immune response observed in patients with severe COVID-19. TLR2, TLR3, TLR4 and TLR7 have been associated with COVID-19 severity. Here, we review the role of TLRs in the etiology and pathogenesis of COVID-19, including TLR7 and TLR3 rare variants, the L412F polymorphism in TLR3 that negatively regulates anti-SARS-CoV-2 immune responses, the TLR3-related cellular senescence, the interaction of TLR2 and TLR4 with SARS-CoV-2 proteins and implication of TLR2 in NET formation by SARS-CoV-2. The activation of TLRs contributes to viral clearance and disease resolution. However, TLRs may represent a double-edged sword which may elicit dysregulated immune signaling, leading to the production of proinflammatory mediators, resulting in severe disease. TLR-dependent excessive inflammation and TLR-dependent antiviral response may tip the balance towards the former or the latter, altering the equilibrium that drives the severity of disease. [ABSTRACT FROM AUTHOR]

VEXAS (Vacuoles, E1 enzyme, X-linked, Autoinflammatory, Somatic) syndrome is a recently described pathological entity. It is an acquired monogenic autoinflammatory disease caused by somatic mutations of the UBA1 gene in blood cells precursors; the gene encodes one of the two E1 enzyme isoforms that initiates ubiquitylation in cell's cytoplasm. VEXAS syndrome leads to systemic inflammation, with all organs and tissues potentially involved. The clinical picture may be extremely heterogenous, mimicking different other systemic rheumatologic entities coexisting with haematological disorders, especially myelodysplastic syndrome. This new disease represents a very intriguing clinical condition in several respects: it accounts for the paradigm of adult-onset monogenic autoinflammatory diseases determined by a genetic mosaicism resulting in the development of a challenging multiorgan inflammatory condition. Moreover, VEXAS syndrome is perhaps not an exceptionally rare condition and represents an example of a systemic genetic autoinflammatory disease drawing its origin in bone marrow disorders. VEXAS syndrome should be strongly considered in each adult patient with an unexplained systemic inflammatory condition, especially when recurrent fevers, neutrophilic dermatosis, relapsing polychondritis, ocular inflammation and other systemic inflammatory symptoms accompanying myelodysplastic syndrome or other haematological disorders. The syndrome deserves a multidisciplinary approach to reach the diagnosis and ensure the best management of a potentially very challenging condition. To quickly describe the clinical course, long-term outcomes, and the optimal management of this new syndrome it is essential to join forces internationally. To this end, the international AutoInflammatory Disease Alliance (AIDA) registry dedicated to VEXAS syndrome has been developed and is already active. [ABSTRACT FROM AUTHOR]

Although adult stem cells may be useful for studying tissue-specific diseases, they cannot be used as a general model for investigating human illnesses given their limited differentiation potential. Multilineage-differentiating stress-enduring (Muse) stem cells, a SSEA3(+) cell population isolated from mesenchymal stromal cells, fat, and skin fibroblasts, may be able to overcome that restriction. The Muse cells present in fibroblast cultures obtained from biopsies of patients' skin may be differentiated into cells of interest for analyzing diseases. We isolated Muse stem cells from patients with an intellectual disability (ID) and mutations in the IQSEC2 gene (i.e., BRAG1 gene) and induced in vitro neuroglial differentiation to study cell commitment and the differentiation of neural lineages. The neuroglial differentiation of Muse cells revealed that IQSEC2 mutations may alter the self-renewal and lineage specification of stem cells. We observed a decrease in the percentage of SOX2 (+) neural stem cells and neural progenitors (i.e., SOX2+ and NESTIN+) in cultures obtained from Muse cells with the mutated IQSEC2 gene. The alteration in the number of stem cells and progenitors produced a bias toward the astrocytes' differentiation. Our research demonstrates that Muse stem cells may represent a new cell-based disease model. [ABSTRACT FROM AUTHOR]

We describe an autosomal dominant disorder associated with loss-of-function variants in the Cell cycle associated protein 1 (CAPRIN1 ; MIM*601178). CAPRIN1 encodes a ubiquitous protein that regulates the transport and translation of neuronal mRNAs critical for synaptic plasticity, as well as mRNAs encoding proteins important for cell proliferation and migration in multiple cell types. We identified 12 cases with loss-of-function CAPRIN1 variants, and a neurodevelopmental phenotype characterized by language impairment/speech delay (100%), intellectual disability (83%), attention deficit hyperactivity disorder (82%) and autism spectrum disorder (67%). Affected individuals also had respiratory problems (50%), limb/skeletal anomalies (50%), developmental delay (42%) feeding difficulties (33%), seizures (33%) and ophthalmologic problems (33%). In patient-derived lymphoblasts and fibroblasts, we showed a monoallelic expression of the wild-type allele, and a reduction of the transcript and protein compatible with a half dose. To further study pathogenic mechanisms, we generated s CAPRIN1 +/− human induced pluripotent stem cells via CRISPR–Cas9 mutagenesis and differentiated them into neuronal progenitor cells and cortical neurons. CAPRIN1 loss caused reduced neuronal processes, overall disruption of the neuronal organization and an increased neuronal degeneration. We also observed an alteration of mRNA translation in CAPRIN1 +/− neurons, compatible with its suggested function as translational inhibitor. CAPRIN1 +/− neurons also showed an impaired calcium signalling and increased oxidative stress, two mechanisms that may directly affect neuronal networks development, maintenance and function. According to what was previously observed in the mouse model, measurements of activity in CAPRIN1 +/− neurons via micro-electrode arrays indicated lower spike rates and bursts, with an overall reduced activity. In conclusion, we demonstrate that CAPRIN1 haploinsufficiency causes a novel autosomal dominant neurodevelopmental disorder and identify morphological and functional alterations associated with this disorder in human neuronal models. [ABSTRACT FROM AUTHOR]

Carriers of single pathogenic variants of the CFTR (cystic fibrosis transmembrane conductance regulator) gene have a higher risk of severe COVID-19 and 14-day death. The machine learning post-Mendelian model pinpointed CFTR as a bidirectional modulator of COVID-19 outcomes. Here, we demonstrate that the rare complex allele [G576V;R668C] is associated with a milder disease via a gain-of-function mechanism. Conversely, CFTR ultra-rare alleles with reduced function are associated with disease severity either alone (dominant disorder) or with another hypomorphic allele in the second chromosome (recessive disorder) with a global residual CFTR activity between 50 to 91%. Furthermore, we characterized novel CFTR complex alleles, including [A238V;F508del], [R74W;D1270N;V201M], [I1027T;F508del], [I506V;D1168G], and simple alleles, including R347C, F1052V, Y625N, I328V, K68E, A309D, A252T, G542*, V562I, R1066H, I506V, I807M, which lead to a reduced CFTR function and thus, to more severe COVID-19. In conclusion, CFTR genetic analysis is an important tool in identifying patients at risk of severe COVID-19. [ABSTRACT FROM AUTHOR]

COVID-19 has shown a relevant heterogeneity in spread and fatality among countries together with a significant variability in its clinical presentation, indicating that host genetic factors may influence COVID-19 pathogenicity. Indeed, subjects carrying single pathogenic variants of the Cystic Fibrosis (CF) Transmembrane Conductance Regulator (CFTR) gene - i.e. CF carriers - are more susceptible to respiratory tract infections and are more likely to undergo severe COVID-19 with higher risk of 14-day mortality. Given that CF carrier prevalence varies among ethnicities and nations, an ecological study in 37 countries was conducted, in order to determine to what extent the diverse CF carrier geographical distribution may have affected COVID-19 spread and fatality during the first pandemic wave. The CF prevalence in countries, as indicator of the geographical distribution of CF carriers, significantly correlated in a direct manner with both COVID-19 prevalence and its Case Fatality Rate (CFR). In a regression study weighted for the number of tests performed, COVID-19 prevalence positively correlated with CF prevalence, while CFR correlated with population percentage older than 65-year, cancer and CF prevalence. Multivariate regression model also confirmed COVID-19 CFR to be associated with CF prevalence, after adjusting for elderly, cancer prevalence, and weighting for the number of tests performed. This study suggests a putative contribution of population genetics of CFTR in understanding the spatial distribution of COVID-19 spread and fatality. [ABSTRACT FROM AUTHOR]

Several different nosological classifications have been used over time for vascular malformations (VMs) since clinical and pathological signs are largely overlapping. In a large proportion of cases, VMs are generated by somatic mosaicism in key genes, belonging to a few different molecular pathways. Therefore, molecular characterization may help in the understanding of the biological mechanisms related to the development of pathology. Tissue biopsy is not routinely included in the diagnostic path because of the need for fresh tissue specimens and the risk of bleeding. Bypassing the need for bioptic samples, we took advantage of the possibility of isolating cell-free DNA likely released by the affected tissues, to molecularly characterize 53 patients by cfDNA-NGS liquid biopsy. We found a good match between the identified variant and the clinical presentation. PIK3CA variants were found in 67% of Klippel Trenaunay Syndrome individuals; KRAS variants in 60% of arteriovenous malformations; MET was mutated in 75% of lymphovenous malformations. Our results demonstrate the power of cfDNA-NGS liquid biopsy in VMs clinical classification, diagnosis, and treatment. Indeed, tailored repurposing of pre-existing cancer drugs, such as PIK3CA, KRAS, and MET inhibitors, can be envisaged as adjuvant treatment, in addition to surgery and/or endovascular treatment, in the above-defined VMs categories, respectively. [ABSTRACT FROM AUTHOR]

Whole exome sequencing has provided significant opportunities to discover novel candidate genes for intellectual disability and autism spectrum disorders. Variants in the spectrin genes SPTAN1, SPTBN1, SPTBN2 , and SPTBN4 have been associated with neurological disorders; however, SPTBN5 gene-variants have not been associated with any human disorder. This is the first report that associates SPTBN5 gene variants (ENSG00000137877: c.266A>C; p.His89Pro, c.9784G>A; p.Glu3262Lys, c.933C>G; p.Tyr311Ter, and c.8809A>T; p.Asn2937Tyr) causing neurodevelopmental phenotypes in four different families. The SPTBN5 -associated clinical traits in our patients include intellectual disability (mild to severe), aggressive tendencies, accompanied by variable features such as craniofacial and physical dysmorphisms, autistic behavior, and gastroesophageal reflux. We also provide a review of the existing literature related to other spectrin genes, which highlights clinical features partially overlapping with SPTBN5. [ABSTRACT FROM AUTHOR]

Introduction: Spastic paraplegia type 11 (SPG11) is the most frequent autosomal recessive HSP. Studies on SPG11 patients' fibroblasts, post-mortem brains, and mouse models revealed endolysosomal system dysfunction and lipid accumulation, especially gangliosides. We report a patient with early clinical findings mimicking a GM2-gangliosidosis. Methods: A clinical, biochemical, and metabolic characterization was performed. Electron microscopy analysis was completed on rectal mucosa and skin biopsy specimens. A NGS panel of genes associated to neuronal ceroid lipofuscinosis and HSP was analyzed. Results: The patient presented with worsening walking difficulty and psychomotor slowdown since childhood; to exclude a neurometabolic storage disease, skin and rectal biopsies were performed: enteric neurons showed lipofuscin-like intracellular inclusions, thus suggesting a possible GM2-gangliosidosis. However, further analysis did not allow to confirm such hypothesis. In adulthood we detected flaccid paraplegia, nystagmus, axonal motor neuropathy, carpus callosum atrophy, and colon atony. Surprisingly, the NGS panel detected two already reported SPG11 mutations in compound heterozygosity. Conclusions: We describe for the first time pathological hallmarks of SPG11 in enteric neuron from a rectal mucosa biopsy. The report illustrates the possible overlap between SPG11 and GM2-gangliosidosis, especially in the first disease phases and helps to improve our knowledge about SPG11 physiopathology. [ABSTRACT FROM AUTHOR]

Genetic defects in the SHANK2 gene, encoding for synaptic scaffolding protein, are associated with a variety of neurodevelopmental conditions, including autism spectrum disorders and mild to moderate intellectual disability. Until now, limited patient clinical descriptions have been published. Only 13 unrelated patients with SHANK2 pathogenic variations or microdeletions have been reported worldwide. By Exome Sequencing, we identified a de novo stop-gain variant, c.334C>T, p.(Gln112*), in an Italian patient with a neurodevelopmental disorder. The patient (9 years old) presented the following facial features: a flat profile, thick eyebrows, long eyelashes, a bulbous nasal tip and a prominent columella, retracted ears, dental anomalies. The patient showed speech delay and mild neuromotor delay but not autism spectrum disorder. In conclusion, this patient with a novel pathogenic variant in SHANK2 enlarges the phenotypic spectrum of SHANK2-mutated patients and demonstrates that the severity of SHANK2-associated disorders is highly variable. [ABSTRACT FROM AUTHOR]

The article describes the case of a female child with neurodevelopmental delay who has been identified with a novel pathogenic variant in the NAGLU gene. The patient underwent RASopathies genes panel analysis by Next Generation Sequencing, brain magnetic resonance imaging (MRI), Exome Sequencing and Sanger sequencing. Results revealed asymmetry of the patient's cerebellar tonsils, subarachnoid cyst in the retrovermian region, presence of cystic pinealoma and NAGLU gene frameshift deletion.

Spondyloocular syndrome (SOS) is a skeletal disorder caused by pathogenic variants in XYLT2 gene encoding a xylotransferase involved in the biosynthesis of proteoglycans. This condition, with autosomal recessive inheritance, has a high phenotypic variability. It is characterized by bone abnormalities (osteoporosis, fractures), eye and cardiac defects, hearing impairment, and varying degrees of developmental delay. Until now only 20 mutated individuals have been reported worldwide. Here, we describe two siblings from consanguineous healthy parents in which a novel homozygous frameshift variant c.1586dup p(Thr530Hisfs*) in the XYLT2 gene was detected by exome sequencing (ES). The first patient (9 years) presented short stature with skeletal defects, long face, hearing loss and cataract. The second patient, evaluated at a few days of life, showed macrosomia, diffuse hypertrichosis on the back, overabundant skin in the retronucal area, flattened facial profile with drooping cheeks, elongated eyelid rims, wide and flattened nasal bridge and turned down corners of the mouth. During the prenatal period, high nuchal translucency and intestinal hyperechogenicity were observed at ultrasound. In conclusion, these two siblings with a novel pathogenic variant in XYLT2 further expand the clinical and mutational spectrum of SOS. [ABSTRACT FROM AUTHOR]

Chromosome 4q deletions are rare disorders phenotypically characterized by several features. The most commonly described ocular abnormalities include unilateral microphthalmia with bilateral colobomata, blue sclerae with pigmented retinal clumps, hypermetropia, and a divergent squint. To report a case of 4q12 deletion with a singular retinal feature. Case report. A 20-year-old Caucasian female with a history of poliosis, progressive appearance of small areas of skin depigmentation along trunk and limbs since birth and diagnosis of learning deficit was referred for a complete ocular examination. The genetic counseling showed microdeletion in the 4q12 region. An audiometric test was performed, showing a progressive bilateral neurosensorial hypoacusia. Ocular examination showed the presence of multifocal, tiny, whitish deposits in the posterior pole. Multimodal imaging defined the lesions as small elevations of the retinal pigment epithelium with slight hyper-autofluorescence and staining in the late phase of fluoresceine angiography (FA). Visual acuity was 20/20. The retinal findings did not change during the three-month follow-up. Although the findings herein reported have never been described before in patients affected by 4q12 mutations, we do not exclude that they could represent a manifestation of the peculiar genetic asset of the patient, related to dysfunction in pigment epithelium/neuroretinal metabolic activity. [ABSTRACT FROM AUTHOR]

We thank John Hatton of the Institute of Biomedical Technologies (CNR-ITB) for proofreading the manuscript. The Cell line and DNA bank of Rett Syndrome, X-linked mental retardation and other genetic diseases, member of the Telethon Network of Genetic Biobanks (project no. The Cell line and DNA bank of Rett Syndrome, X-linked mental retardation and other genetic diseases, member of the Telethon Network of Genetic Biobanks (project no. [Extracted from the article]

Autism spectrum disorders (ASD) are a group of complex neurodevelopmental disorders, characterized by a deficit in social interaction and communication. Many genetic variants are associated with ASD, including duplication of 7q11.23 encompassing 26–28 genes. Symmetrically, the hemizygous deletion of 7q11.23 causes Williams–Beuren syndrome (WBS), a multisystem disorder characterized by "hyper-sociability" and communication skills. Interestingly, deletion of four non-exonic mobile elements (MEs) in the "canine WBS locus" were associated with the behavioral divergence between the wolf and the dog and dog sociability and domestication. We hypothesized that indel of these MEs could be involved in ASD, associated with its different phenotypes and useful as biomarkers for patient stratification and therapeutic design. Since these MEs are non-exonic they have never been discovered before. We searched the corresponding MEs and loci in humans by comparative genomics. Interestingly, they mapped on different but ASD related genes. The loci in individuals with phenotypically different autism and neurotypical controls were amplified by PCR. A sub-set of each amplicon was sequenced by Sanger. No variant resulted associated with ASD and neither specific phenotypes were found but novel small-scale insertions and SNPs were discovered. Since MEs are hyper-methylated and epigenetically modulate gene expression, further investigation in ASD is necessary. [ABSTRACT FROM AUTHOR]

Retinoblastoma (RB) is an ocular tumor of the pediatric age caused by biallelic inactivation of the RB1 gene (13q14). About 10% of cases are due to gross-sized molecular deletions. The deletions can involve the surrounding genes delineating a contiguous gene syndrome characterized by RB, developmental anomalies, and peculiar facial dysmorphisms. Overlapping deletions previously found by traditional and/or molecular cytogenetic analysis allowed to define some critical regions for intellectual disability (ID) and multiple congenital anomalies, with key candidate genes. In the present study, using array-CGH, we characterized seven new patients with interstitial 13q deletion involving RB1. Among these cases, three patients with medium or large 13q deletions did not present psychomotor delay. This allowed defining a minimal critical region for ID that excludes the previously suggested candidate genes (HTR2A, NUFIP1, PCDH8, and PCDH17). The region contains 36 genes including NBEA, which emerged as the candidate gene associated with developmental delay. In addition, MAB21L1, DCLK1, EXOSC8, and SPART haploinsufficiency might contribute to the observed impaired neurodevelopmental phenotype. In conclusion, this study adds important novelties to the 13q deletion syndrome, although further studies are needed to better characterize the contribution of different genes and to understand how the haploinsufficiency of this region can determine ID. [ABSTRACT FROM AUTHOR]

Objective: Bipolar disorder is a heritable chronic mental disorder that causes psychosocial impairment through depressive/manic episodes. Familial transmission of bipolar disorder does not follow simple Mendelian patterns of inheritance. The aim of this study was to describe a large family with 12 members affected by bipolar disorder. Whole-exome sequencing was performed for eight members, three of whom were diagnosed with bipolar disorder, and another reported as "borderline". Methods: Whole-exome sequencing data allowed us to select variants that the affected members had in common, including and excluding the "borderline" individual with moderate anxiety and obsessivecompulsive traits. Results: The results favored designating certain genes as predispositional to bipolar disorder: a heterozygous missense variant in CLN6 resulted in a "borderline" phenotype that, if combined with a heterozygous missense variant in ZNF92, is responsible for the more severe bipolar disorder phenotype. Both rare missense changes are predicted to disrupt protein function. Conclusions: Loss of both alleles in CLN6 causes neuronal ceroid lipofuscinosis, a severe progressive childhood neurological disorder. Our results indicate that heterozygous CLN6 carriers, previously reported as healthy, may be susceptible to bipolar disorder later in life if associated with additional variants in ZNF92. [ABSTRACT FROM AUTHOR]