Small nuclear RNAs (snRNAs) are essential components of the spliceosome. De novo variants in snRNA genes RNU4-2 (ReNU syndrome), RNU5B-1 and RNU2-2 have been linked to dominant neurodevelopmental disorders (NDDs), revealing a large unexpected contribution of noncoding RNA genes to genetic diseases. Here, through international collaborations, we analyze systematically 200 potentially functional snRNA genes in a French cohort of 34,329 people with rare disorders. We report RNU2-2 variants in 141 individuals, including 35 with recurrent dominant pathogenic variants and 91 affected members from 73 families with biallelic variants. Recessive RNU2-2 NDD is at least twice as frequent as the dominant form and often involves a de novo variant in trans with an inherited allele, consistent with the high mutability of snRNA genes. Dominant and recessive RNU2-2 NDDs share overlapping clinical features, with frequent epilepsy. Blood transcriptomics and DNA methylation analyses revealed subtle, variant-specific effects on splicing and episignatures. Our results support a gradient-of-impact model bridging dominant and recessive inheritance, and establish RNU2-2 variants as a principal contributor to NDDs, nearly as prevalent as ReNU syndrome.

Developmental Delay, Epileptic Encephalopathy, Cerebral Atrophy, and Abnormal Myelination syndrome (DECAM syndrome) is a rare autosomal recessive neurodevelopmental disorder with developmental delay, epileptic encephalopathy, cerebral atrophy, severe intellectual disability, and autistic features. It is also called Developmental and Epileptic Encephalopathy 76 (DEE76). In this report, we present two cases of DECAM syndrome, a 5-year-old boy and a 9-year-old girl, who presented with refractory seizures, microcephaly and severe developmental delay. Although both patients had homozygous mutation in the ACTL6B gene, the time of onset and clinical severity of the disease were different. We attributed this to the mutations being in different regions and aimed to emphasize the importance of genotype-phenotype correlation.

Variants in spliceosomal small nuclear RNA (snRNA) genes RNU4-2 (ReNU syndrome), RNU5B-1, and RNU2-2 have recently been linked to dominant neurodevelopmental disorders (NDDs), revealing a major, previously overlooked role for noncoding snRNAs in human disease. Here, we systematically analysed 200 potentially functional snRNA genes in a French cohort comprising 26,911 individuals with rare disorders and through international collaborations. We identify de novo and biallelic variants in RNU2-2 associated with both dominant and recessive NDDs in 126 individuals from 108 unrelated families. Recessive RNU2-2 NDD is at least twice as frequent as the dominant NDD caused by n.4G>A and n.35A>G, and often arises from a de novo variant in trans with an inherited allele, reflecting the high mutability of snRNA genes. Dominant and recessive RNU2-2-NDDs share overlapping clinical features with frequent epilepsy. Blood transcriptomics and DNA methylation analyses revealed subtle, variant-specific effects on splicing and episignatures. Our findings support a gradient-of-impact model and a continuum between dominant and recessive inheritance, establishing RNU2-2 variants as a frequent cause of NDDs, nearly as prevalent as ReNU syndrome.

Objectives Prader–Willi syndrome (PWS) is a rare and complex genetic disorder caused by the loss of expression of the paternal copy of the imprinted genes on chromosome 15q11-q13. A variety of findings have been reported on the phenotypic differences between the genetic subtypes of PWS. This article compares the clinical findings of 57 PWS patients by genetic subtype and explores possible associations in this context. Methods Methylation‑specific multiplex ligation–dependent probe amplification and single nucleotide polymorphism microarrays were used to diagnose deletion and uniparental disomy (UPD). For phenotype–genotype correlation, clinical data were collected and genetic subgroups were compared statistically, and P < 0.05 was considered to indicate statistical significance. Results These 57 patients consisted of 15 type I deletions, 20 type II deletions, six atypic deletions, 11 heterodisomy UPD, four isodisomy UPD, and one translocation-type PWS. All patients had hypotonia, poor neonatal sucking, and feeding difficulties during infancy. Other PWS-related clinical findings, such as speech articulation problems (85.9%), sleep apnea (77.2%), normal birth length (71.9%), small hands/feet (71.9%), childhood polyphagia (57.9%), clinodactyly (56.1%), thick viscous saliva (54.4%), and behavioral problems (50.9%) were observed at varying rates with no statistical difference between genetic subtypes in general. Conclusion This study highlights the phenotype–genotype associations on PWS from a cohort of Turkish pediatric patients as a single-center experience.

POU3F3 variants cause developmental delay, behavioral problems, hypotonia and dysmorphic features. We investigated the phenotypic and genetic landscape, and genotype-phenotype correlations in individuals with POU3F3-related disorders. We recruited unpublished individuals with POU3F3 variants through international collaborations and obtained updated clinical data on previously published individuals. Trio exome sequencing or single exome sequencing followed by segregation analysis were performed in the novel cohort. Functional effects of missense variants were investigated with 3D protein modeling. We included 28 individuals (5 previously published) from 26 families carrying POU3F3 variants; 23 de novo and one inherited from an affected parent. Median age at study inclusion was 7.4 years. All had developmental delay mainly affecting speech, behavioral difficulties, psychiatric comorbidities and dysmorphisms. Additional features included gastrointestinal comorbidities, hearing loss, ophthalmological anomalies, epilepsy, sleep disturbances and joint hypermobility. Autism, hearing and eye comorbidities, dysmorphisms were more common in individuals with truncating variants, whereas epilepsy was only associated with missense variants. In silico structural modeling predicted that all (likely) pathogenic variants destabilize the DNA-binding region of POU3F3. Our study refined the phenotypic and genetic landscape of POU3F3-related disorders, it reports the functional properties of the identified pathogenic variants, and delineates some genotype-phenotype correlations.

The aim of this in vitro study is to evaluate the effect of antioxidant lycopene on human osteoblasts. The human osteoblast cell line (CRL-11372) was obtained from the American Type Culture Collection (ATCC Manassas, Va) and grown in Dulbecco’s Modified Eagle’s medium (DMEM) supplemented with 10

Background. METTL5 gene is one of the members of methyltransferase superfamily and biallelic variants cause intellectual disability syndrome (ID) with microcephaly. This article reports three new cases with METTL5 related ID syndrome in a consanguineous family. Case. Afghanistan descent family was affected by a novel homozygous c.362A>G (p.Asp121Gly) METTL5 gene variant. This variant is predicted to be "pathogenic" by multiple in-silico tools. Patients had dysmorphic and neurodevelopmental features including intellectual disability, microcephaly, poor/absent speech, delayed walking, aggressive behavior, large/posteriorly rotated ears, broad nasal base and short stature, which seem to be the cardinal findings of the designated syndrome. Conclusions. While the data reported in these individuals indicate characteristic clinical features of METTL5 related ID syndrome, further investigations and study of additional cases are needed to improve the understanding of disease pathogenesis, and management.

POU3F3 proteins are eukaryotic transcription factors and contribute to the processes in the development of brain and kidney. Pathogenic POU3F3 variants cause a neurodevelopmental disorder called Snijders Blok‐Fisher syndrome (SNIBFIS). This article reports a new SNIBFIS case harboring a novel heterozygous c.1018_1019delCAinsTT (p.Gln340Leu) variant in the POU3F3 gene. This variant affects the α2 helix of POU‐S domain and is predicted to be “pathogenic” by multiple in‐silico tools. The proband had severe intellectual disability, hypotonia, autistic features, sleep disturbances, and dysmorphic features. The association with epilepsy and hemangioma like two of the three previously reported patients with mutations in the POU‐S domain was also a remarkable finding to understand the importance of POU‐S domain. This clinical report also highlights the interest of reinterpretation of molecular data and brings a new perspective to the genotype–phenotype relationship in “Snijders Blok‐Fisher syndrome”.

Dubowitz syndrome (DubS) is considered a recognizable syndrome characterized by a distinctive facial appearance and deficits in growth and development. There have been over 200 individuals reported with Dubowitz or a "Dubowitz-like" condition, although no single gene has been implicated as responsible for its cause. We have performed exome (ES) or genome sequencing (GS) for 31 individuals clinically diagnosed with DubS. After genome-wide sequencing, rare variant filtering and computational and Mendelian genomic analyses, a presumptive molecular diagnosis was made in 13/27 (48%) families. The molecular diagnoses included biallelic variants in SKIV2L, SLC35C1, BRCA1, NSUN2; de novo variants in ARID1B, ARID1A, CREBBP, POGZ, TAF1, HDAC8, and copy-number variation at1p36.11(ARID1A), 8q22.2(VPS13B), Xp22, and Xq13(HDAC8). Variants of unknown significance in known disease genes, and also in genes of uncertain significance, were observed in 7/27 (26%) additional families. Only one gene, HDAC8, could explain the phenotype in more than one family (N = 2). All but two of the genomic diagnoses were for genes discovered, or for conditions recognized, since the introduction of next-generation sequencing. Overall, the DubS-like clinical phenotype is associated with extensive locus heterogeneity and the molecular diagnoses made are for emerging clinical conditions sharing characteristic features that overlap the DubS phenotype.

Objectives: Carbonic anhydrase VA (CAVA) deficiency is a rare autosomal recessive inborn error of metabolism that leads to acute metabolic crises, especially in the neonatal or infantile period. It is caused by a deficiency of the enzyme CAVA, which is encoded by the CA5A gene. Case presentation: Fifteen patients with homozygous pathogenic CA5A mutations involving 10 different lesions have been reported in the literature up to date. Main clinical and biochemical features of CAVA deficiency include lethargy, hyperammonemic encephalopathy, metabolic acidosis, elevated lactate and hypoglycemia. In most patients reported so far, a single metabolic decompensation attack has been reported, and they have remained stable thereafter with no further crisis. Conclusions: We report the 16th case of CAVA deficiency, who was diagnosed by whole-exome sequencing and showed a typical course of the disease with normal development at 18 months.

BACKGROUND AND OBJECTIVE:Patients with Klinefelter Syndrome (KS) have increased cardiometabolic risk however the pathogenesis is not clear. We investigated the presence of endothelial dysfunction, insulin resistance and inflammation in an unconfounded population of KS.METHODS:A total of 32 patients with KS (mean age 21.59 ± 1.66 years) and 33 healthy control subjects (mean age: 22.15 ± 1.03 years) were enrolled. The demographic parameters, Asymmetric dimethylarginine (ADMA), homeostatic model assessment of insulin resistance (HOMA-IR) index and highsensitivity C-reactive protein (hs-CRP) levels were measured.RESULTS:The patients had higher Follicle Stimulating Hormone (FSH), Luteinizing Hormone (LH), insulin, HOMA-IR and ADMA levels (p < 0.001 for all) and lower High Density Lipoprotein Cholesterol (HDL-C) and total testosterone levels (p=0.002 and p<0.001, respectively), compared to the healthy controls. Total testosterone levels were significantly negatively correlated to ADMA (r = - 0.479, p < 0,001), hs-CRP (r = -0.291, p = 0.034) and positively correlated to HDL-C (r = 0.429, p = 0.001) levels. The multivariate analysis has shown that total testosterone (β = -0.412, p = 0.001) and TG (β = 0.332, p = 0.009) levels were the significant independent determinants of the plasma ADMA levels.CONCLUSION:The results of the present study show that endothelial dysfunction and insulin resistance are prevalent even in the very young subjects with KS, who have no metabolic or cardiac problems at present. Also, hypogonadism seems to play an important role for increased cardiometabolic risk in patients with KS.

OBJECTIVES:The primary purpose of this study was to examine the effects of triethylene glycol dimethacrylate (TEGDMA) on odontoclastic differentiation in the dental pulp tissue. MATERIAL AND METHODS:The effects of different TEGDMA dosages on the odontoclastic differentiation capability of dental pulp cells were analyzed in vitro using the following methodologies: i) flow cytometry and tartrate-resistant acid phosphatase (TRAP) staining; ii) apoptotic effects using Annexin V staining; iii) mRNA expression of osteoprotegerin (OPG) and receptor activator of nuclear factor (NF)-kB ligand (RANKL) genes by quantitative Real-time PCR (qRT-PCR); and iv) OPG and RANKL protein expression by enzyme-linked immunosorbent assay (ELISA). RESULTS:TEGDMA caused relatively less odontoclastic differentiation in comparison with the control group; however, odontoclastic differentiation augmented with increasing doses of TEGDMA (p<0.05). The mRNA and protein expression of OPG was lower in TEGDMA treated pulp cells than in the control group (p<0.05). While the mRNA expression of RANKL remained unchanged compared to the control group (p>0.05), its protein expression was higher than the control group (p<0.05). In addition, TEGDMA increased the apoptosis of dental pulp cells dose dependently. CONCLUSIONS:TEGDMA reduced the odontoclastic differentiation ability of human dental pulp cells. However, odontoclastic differentiation ratios increased proportionally with the increasing dose of TEGDMA.

Purpose: To compare homocysteine and thrombophilic mutations for the methylenetetrahydrofolate reductase (MTHFR) C677T, factor V Leiden, and prothrombin G20210A between retinal vein occlusion (RVO) and healthy controls in a Turkish population.Materials and methods: Forty-nine subjects with RVO were compared for homocysteine status and the MTHFR C677T, prothrombin G20210A, and factor V Leiden mutations with those of 68 healthy controls. Then, the groups were subdivided into two subgroups according to age (less than 50 years old, equal to or more than 50 years old) and were further compared.Results: Mean plasma level of homocysteine was similar, but the frequency of hyperhomocysteinemia was significantly higher in the RVO group when compared with the control group (22.5% and 8.8%, respectively, p = 0.037). The frequency of all thrombophilic mutations was similar between the groups (p > 0.05). The frequency of all thrombophilic mutations and homocysteine levels was also similar between age subgroups (p > 0.05). Only hyperhomocysteinemia was significantly different between subgroups (p = 0.037); the frequency of hyperhomocysteinemia was significantly different in. RVO patients less than 50 years old (22.7%) from that in healthy controls less than 50 years old (11.1%). Two RVO patients (4.1%) with bilateral involvement had MTHFR C677T mutation.Conclusions: Screening for thrombophilic mutations such as MTHFR C677T, factor V Leiden, and pro thrombin G20210A in RVO patients at all ages seems to be unnecessary and not cost-effective. However, thrombophilic disorders should be screened selectively, focusing, on young individuals, especially with bilateral involvement, without additional cardiovascular risk factors, or a family history of thrombosis.

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