Biallelic variants in CTU2 cause DREAM-PL syndrome and impair thiolation of tRNA wobble U34.

The wobble position in the anticodon loop of transfer ribonucleic acid (tRNA) is subject to numerous posttranscriptional modifications. In particular, thiolation of the wobble uridine has been shown to play an important role in codon-anticodon interactions. This modification is catalyzed by a highly conserved CTU1/CTU2 complex, disruption of which has been shown to cause abnormal phenotypes in yeast, worms, and plants. We have previously suggested that a single founder splicing variant in human CTU2 causes a novel multiple congenital anomalies syndrome consisting of dysmorphic facies, renal agenesis, ambiguous genitalia, microcephaly, polydactyly, and lissencephaly (DREAM-PL). In this study, we describe five new patients with DREAM-PL phenotype and whose molecular analysis expands the allelic heterogeneity of the syndrome to five different alleles; four of which predict protein truncation. Functional characterization using patient-derived cells for each of these alleles, as well as the original founder allele; revealed a specific impairment of wobble uridine thiolation in all known thiol-containing tRNAs. Our data establish a recognizable CTU2-linked autosomal recessive syndrome in humans characterized by defective thiolation of the wobble uridine. The potential deleterious consequences for the translational efficiency and fidelity during development as a mechanism for pathogenicity represent an attractive target of future investigations.

A De novo HDAC2 variant in a patient with features consistent with Cornelia de Lange syndrome phenotype.

Cornelia de Lange syndrome (CdLS) is an autosomal dominant genetic disorder caused by pathogenic variants in NIPBL, RAD21, SMC3, HDAC8, or SMC1A; all of which code for proteins that are components of, or interact with, the cohesin complex. Despite the identification of multiple genes associated with CdLS, over 25% of individuals strongly suspected to have CdLS have negative genetic testing, indicating that there are additional genes associated with the condition. HDAC2 codes for histone deacetylase 2 (HDAC2) and, like HDAC8, is a Class 1 histone deacetylase. We present a patient with a novel de novo variant in HDAC2 with many clinical features consistent with CdLS including severe developmental delay, limb abnormalities, congenital heart defect, cryptorchidism and hypoplastic genitalia, growth retardation, and characteristic craniofacial features. Although variants in HDAC2 are not currently associated with human disease, the variant identified in this patient is within a highly conserved amino acid residue and has not been observed in healthy populations. This information, along with the patient's clinical presentation and the functional similarity between the HDAC2 and HDAC8 proteins, suggests that HDAC2 should be further investigated as a candidate gene for CdLS or a CdLS-like syndrome.

A Rare Co-occurrence of Williams Syndrome and 𝘛𝘕𝘒2 Gene-Related Epilepsy.

Williams syndrome is a multisystem disorder characterized by developmental delay, characteristic facial features, growth abnormalities, and cardiovascular abnormalities. The disorder is an autosomal dominant genetic syndrome that occurs due to microdeletion at chromosomal locus 7q11.23. Seizures occur uncommonly in association with Williams syndrome. Mutations in the TNK2 gene have been found in rare cases of autosomal recessive infantile-onset epilepsy. We describe a rare co-occurrence of Williams syndrome and TNK2 gene-related epilepsy in a child born of consanguineous parents. This case report emphasizes the role of genetic testing in the diagnosis of rare diseases. This is the fourth case report of epilepsy with biallelic mutations in the TNK2 gene, to the best of the authors' knowledge.

Novel mutation identified in CONT3 causes IDDSADF: a case report and literature review.

The carbon catabolite repression 4-negative on TATA-less transcription complex subunit 3 gene (CONT3) plays a key role in regulating the mRNA transcription and protein translation of other genes. Mutations in CONT3 have also recently been implicated as a causative factor of intellectual developmental disorder with speech delay, autism, and dysmorphic facies (IDDSADF). However, to date, only a few CONT3 mutations have been reported to be associated with IDDSADF-related diseases. In the present case, we report a Chinese patient with developmental delay, verbal regression, and facial dysmorphism, in whom cerebral magnetic resonance imaging showed an expansion of the lateral ventricle. The patient was diagnosed with an IDDSADF-related disease caused by a de novo c.1616_1623del mutation in exon 14 of CONT3, which was confirmed by whole-exome sequencing and direct Sanger sequencing. This case report is the first known documentation of a pathogenic mutation at the c.1616_1623del locus of CONT3 in the worldwide population. It provides a critical theoretical basis for the specific gene-based diagnosis of IDDSADF-related diseases and expands the mutation profile of CONT3.

Epilepsy as a Novel Phenotype of BPTF-Related Disorders.

BACKGROUND: Neurodevelopmental disorder with dysmorphic facies and distal limb anomalies (NEDDFL) is associated to BPTF gene haploinsufficiency. Epilepsy was not included in the initial descriptions of NEDDFL, but emerging evidence indicates that epileptic seizures occur in some affected individuals. This study aims to investigate the electroclinical epilepsy features in individuals with NEDDFL. METHODS: We enrolled individuals with BPTF-related seizures or interictal epileptiform discharges (IEDs) on electroencephalography (EEG). Demographic, clinical, genetic, raw EEG, and neuroimaging data as well as response to antiseizure medication were assessed. RESULTS: We studied 11 individuals with a null variant in BPTF, including five previously unpublished ones. Median age at last observation was 9 years (range: 4 to 43 years). Eight individuals had epilepsy, one had a single unprovoked seizure, and two showed IEDs only. Key features included (1) early childhood epilepsy onset (median 4 years, range: 10 months to 7 years), (2) well-organized EEG background (all cases) and brief bursts of spikes and slow waves (50% of individuals), and (3) developmental delay preceding seizure onset. Spectrum of epilepsy severity varied from drug-resistant epilepsy (27%) to isolated IEDs without seizures (18%). Levetiracetam was widely used and reduced seizure frequency in 67% of the cases. CONCLUSIONS: Our study provides the first characterization of BPTF-related epilepsy. Early-childhood-onset epilepsy occurs in 19% of subjects, all presenting with a well-organized EEG background associated with generalized interictal epileptiform abnormalities in half of these cases. Drug resistance is rare.

A Rare Case of Hao-Fountain Syndrome Mimicking Fragile X Syndrome.

Hao-Fountain syndrome (HAFOUS) is a rare neurodevelopmental disorder caused by mutations in the ubiquitin-specific protease 7 (USP7) gene for endosomal recycling. The diagnosis is often challenging due to the nonspecific presentation of intellectual disability and developmental delay, often accompanied by dysmorphic facies. In this case, we present an 18-year-old female with intellectual disability (ID), attention-deficit/hyperactivity disorder (ADHD), and dysmorphic facies who had undergone single nucleotide polymorphism (SNP) microarray and fragile X polymerase chain reaction (PCR) testing five years prior to diagnosis, both returning with negative results for genetic anomalies. The patient was managed symptomatically for ADHD until recently when the topic of a possible genetic condition was reintroduced to the family, who were agreeable to a referral to a medical geneticist and repeat genetic testing. Repeat testing, but now with whole-exome sequence (WES) analysis, revealed a pathogenic variant of the USP7 gene, prompting the diagnosis of Hao-Fountain syndrome. Our patient continues to be symptomatically managed for ADHD and intellectual disability. Educational resources and support group information were also shared and discussed with the patient and her family in the wake of this rare diagnosis.

Novel Missense Variant in Heterozygous State in the BRPF1 Gene Leading to Intellectual Developmental Disorder With Dysmorphic Facies and Ptosis.

Intellectual developmental disorder with dysmorphic facies and ptosis is an autosomal dominant condition characterized by delayed psychomotor development, intellectual disability, delayed speech, and dysmorphic facial features, mostly ptosis. Heterozygous mutations in bromodomain and plant homeodomain (PHD) finger containing one (BRPF1) gene have been reported. In this study, whole exome sequencing (WES) was performed as a molecular diagnostic test. Bioinformatics of WES data and candidate gene prioritization identified a novel variant in heterozygous state in the exon 3 of BRPF1 gene (ENST383829: c.1054G > C and p.Val352Leu). Autosomal dominant inheritance in the family affected individuals and exclusion of non-pathogenicity in the ethnically matched healthy controls (n = 100) were performed by Sanger sequencing. To the best of our knowledge, this is the first evidence of BRPF1 variant in a Saudi family. Whole exome sequencing analysis has been proven as a valuable tool in the molecular diagnostics. Our findings further expand the role of WES in efficient disease diagnosis in Arab families and explained that the mutation in BRPF1 gene plays an important role for the development of IDDFP syndrome.

Next generation sequencing reveals novel homozygous frameshift in PUS7 and splice acceptor variants in AASS gene leading to intellectual disability, developmental delay, dysmorphic feature and microcephaly.

Intellectual developmental disorder with abnormal behavior, microcephaly and short stature (IDDABS), (OMIM# 618342) is an autosomal recessive condition described as developmental delay, poor or absent speech, intellectual disability, short stature, mild to progressive microcephaly, delayed psychomotor development, hyperactivity, seizure, along with mild to swear aggressive behavior. Homozygous frameshift mutation in Pseudouridine Synthase 7, Putative; (PUS7) OMIM# 616,261 NM_019042.3 and splice acceptor variants in Alpha-Aminoadipic Semialdehyde Synthase; (AASS) OMIM# 605,113 NM_005763.3 was funded. Whole exome sequencing (WES) technique was used as tool to identify the molecular diagnostic test. Different bioinformatics analysis done for WES data and we identified two novel mutations one as frameshift mutation c.606_607delGA, p.Ser282CysfsTer9 in the PUS7 gene and splice acceptor variants c.1767-1 G > A in the AASS gene has been reported. The pattern of family segregation maintained the pathogenicity of this variation associated with abnormal behavior, intellectual developmental disorder, microcephaly along with short stature IDDABS. Further, the WES data was validated in the family having other affected individuals and healthy controls (n = 100) was done using Sanger sequencing. Finally, our results further explained the role of WES in the disease diagnosis and elucidated that the mutation in PUS7 and AASS genes may lead an important role for the development of IDDABS in Saudi family.

Case report of intellectual developmental disorder with dysmorphic facies and behavioral abnormalities due to FBXO11 gene mutation / 中华实用儿科临床杂志

A retrospective analysis was performed on the clinical data of a case of intellectual developmental disorders with dysmorphic facies and behavioral abnormalities admitted in the Department of Neurology and Endocrinology, Children′s Hospital Affiliated to Shandong University in February 2020.The proband was a 3 years and 6 months old boy, who was hospitalized because of " convulsions for more than 1 year" . Physical examination revealed facial deformities.Gesell developmental schedule showed that adaptive and gross motor behavior development was severely retarded, and fine motor, language and personal-social behavior development was moderately retarded.Brain magnetic resonance imaging suggested schizencephaly.Electroencephalogram results indicated extensive discharges mainly in bilateral anterior head areas, and one myoclonic seizure was detected.Gene detection results disclosed the pathogenic variation of the proband, which was a heterozygote mutation (c.2480_2484del) in FBXO11 gene.High-throughput sequencing technology increases the possibility of identifying potential genetic mutations as the cause of disease.Patients with recurrent seizures, multi-malformation and general developmental delays should undergo gene detection in time to clarify the etiology.This technique can guide prenatal diagnosis and genetic counseling.

Case report of intellectual developmental disorder with dysmorphic facies and behavioral abnormalities due to FBXO11 gene mutation / 中华实用儿科临床杂志

A retrospective analysis was performed on the clinical data of a case of intellectual developmental disorders with dysmorphic facies and behavioral abnormalities admitted in the Department of Neurology and Endocrinology, Children′s Hospital Affiliated to Shandong University in February 2020.The proband was a 3 years and 6 months old boy, who was hospitalized because of " convulsions for more than 1 year" . Physical examination revealed facial deformities.Gesell developmental schedule showed that adaptive and gross motor behavior development was severely retarded, and fine motor, language and personal-social behavior development was moderately retarded.Brain magnetic resonance imaging suggested schizencephaly.Electroencephalogram results indicated extensive discharges mainly in bilateral anterior head areas, and one myoclonic seizure was detected.Gene detection results disclosed the pathogenic variation of the proband, which was a heterozygote mutation (c.2480_2484del) in FBXO11 gene.High-throughput sequencing technology increases the possibility of identifying potential genetic mutations as the cause of disease.Patients with recurrent seizures, multi-malformation and general developmental delays should undergo gene detection in time to clarify the etiology.This technique can guide prenatal diagnosis and genetic counseling.