Seizures as an Atypical Feature of Beal’s Syndrome

Congenital contractural arachnodactyly, commonly known as Beal’s syndrome, is an extremely rare genetic disorder caused by mutations in the fibrillin-2 (FBN2) gene located on chromosome 5q23. It is an autosomal dominant inherited connective tissue disorder characterised by a Marfan-like body habitus, contractures, abnormally shaped ears and kyphoscoliosis. We report a seven-year-old Omani male who presented to the Sultan Qaboos University Hospital, Muscat, Oman, in 2014 with seizures. He was noted to have certain distinctive facial features and musculoskeletal manifestations; he was subsequently diagnosed with Beal’s syndrome. Sequencing of the FBN2 gene revealed that the patient had a novel mutation which was also present in his mother; however, she had only a few facial features indicative of Beal’s syndrome and no systemic involvement apart from a history of childhood seizures. To the best of the authors’ knowledge, this is the first report of Beal’s syndrome with seizure symptoms as a potential feature

Coexistence of Autism Spectrum Disorders Among Three Children with Tuberous Sclerosis Complex : Case reports and review of literature

Tuberous sclerosis complex (TSC) is a multisystem neurocutaneous disorder inherited in an autosomal dominant manner and characterised by benign tumours in the brain and other vital organs such as the heart, eyes, kidneys, skin and lungs. Links between autism spectrum disorder (ASD) and TSC have been postulated for many decades, with TSC considered to be one of the main syndromic causes of ASD; however, precise confirmation of a relationship between these two disorders required validated diagnostic tools. Fortunately, accurate evaluation of this relationship is now possible with standardised criteria for ASD diagnosis. We report three children who presented to the Sultan Qaboos University Hospital, Muscat, Oman, between 2014 and 2015 with ASD and TSC. These cases demonstrate the spectrum of neuropsychiatric involvement in TSC and highlight the importance of screening children with TSC for ASD features in order to encourage the early enrolment of these children in educational and rehabilitation programmes

De Novo Duplication of 7p21.1p22.2 in a Child with Autism Spectrum Disorder and Craniofacial Dysmorphism

The duplication of the short arm of chromosome 7 as de novo is extremely rare. The phenotype spectrum varies depending on the region of duplication. We report a case of de novo duplication of chromosomal region 7p21.1p22.2 in a three-year-old male child with autism who presented to the Sultan Qaboos University Hospital in Muscat, Oman, in January 2012. The patient was diagnosed with craniofacial dysmorphism, global developmental delay, hypotonia and bilateral cryptorchidism. The duplication was detected by conventional G-banded karyotype analysis/fluorescence in situhybridisation and confirmed by array comparative genomic hybridisation. To the best of the authors’ knowledge, this is the first report of chromosomal region 7p21.1 involvement in an autistic patient showing features of a 7p duplication phenotype. Identifying genes in the duplicated region using molecular techniques is recommended to promote characterisation of the phenotype and associated condition. It may also reveal the possible role of these genes in autism spectrum disorder

Impact of BRAF, MLH1 on the incidence of microsatellite instability high colorectal cancer in populations based study

We have identified an alternative pathway of tumorigenesis in sporadic colon cancer, involving microsatellite instability due to mismatched repair methylation, which may be driven by mutations in the BRAF gene (V600E). Colorectal cancer (CRC) is the most common cancer in the world, and African Americans show a higher incidence than other populations in the United States. We analyzed sporadic CRCs in Omani (of African origin, N = 61), Iranian (of Caucasian origin, N = 53) and African American (N = 95) patients for microsatellite instability, expression status of mismatched repair genes (hMLH1, hMSH2) and presence of the BRAF (V600E) mutation. In the Omani group, all tumors with BRAF mutations were located in the left side of the colon, and for African Americans, 88% [7] of tumors with BRAF mutations were found in the right side of the colon. In African Americans, 31% of tumors displayed microsatellite instability at two or more markers (MSI-H), while this rate was 26% and 13% for tumors in the Iranian and Omani groups, respectively. A majority of these MSI-H tumors were located in the proximal colon (right side) in African American and Iranian subjects, whereas most were located in the distal colon (left side) in Omani subjects. Defects in hMLH1 gene expression were found in 77% of MSI-H tumors in both African Americans and Iranians and in 38% of tumors in Omanis. BRAF mutations were observed in all subjects: 10% of tumors in African Americans (8/82), 2% of tumors in Iranians (1/53), and 19% of tumors in Omanis (11/59). Our findings suggest that CRC occurs at a younger age in Omani and Iranian patients, and these groups showed a lower occurrence of MSI-H than did African American patients. Our multivariate model suggests an important and significant role of hMLH1 expression and BRAF mutation in MSI-H CRC in these populations. The high occurrence of MSI-H tumors in African Americans may have significant implications for treatment, since patients with MSI-H lesions display a different response to chemotherapeutic agents such as 5-fluorouracil

De Novo Duplication of 7p21.1p22.2 in a Child with Autism Spectrum Disorder and Craniofacial Dysmorphism

The duplication of the short arm of chromosome 7 as de novo is extremely rare. The phenotype spectrum varies depending on the region of duplication. We report a case of de novo duplication of chromosomal region 7p21.1p22.2 in a three-year-old male child with autism who presented to the Sultan Qaboos University Hospital in Muscat, Oman, in January 2012. The patient was diagnosed with craniofacial dysmorphism, global developmental delay, hypotonia and bilateral cryptorchidism. The duplication was detected by conventional G-banded karyotype analysis/fluorescence in situ hybridisation and confirmed by array comparative genomic hybridisation. To the best of the authors’ knowledge, this is the first report of chromosomal region 7p21.1 involvement in an autistic patient showing features of a 7p duplication phenotype. Identifying genes in the duplicated region using molecular techniques is recommended to promote characterisation of the phenotype and associated condition. It may also reveal the possible role of these genes in autism spectrum disorder

A novel mutation in DDR2 causing spondylo-meta-epiphyseal dysplasia with short limbs and abnormal calcifications (SMED-SL) results in defective intra-cellular trafficking

BACKGROUND: The rare autosomal genetic disorder, Spondylo-meta-epiphyseal dysplasia with short limbs and abnormal calcifications (SMED-SL), is reported to be caused by missense or splice site mutations in the human discoidin domain receptor 2 (DDR2) gene. Previously our group has established that trafficking defects and loss of ligand binding are the underlying cellular mechanisms of several SMED-SL causing mutations. Here we report the clinical characteristics of two siblings of consanguineous marriage with suspected SMED-SL and identification of a novel disease-causing mutation in the DDR2 gene. METHODS: Clinical evaluation and radiography were performed to evaluate the patients. All the coding exons and splice sites of the DDR2 gene were sequenced by Sanger sequencing. Subcellular localization of the mutated DDR2 protein was determined by confocal microscopy, deglycosylation assay and Western blotting. DDR2 activity was measured by collagen activation and Western analysis. RESULTS: In addition to the typical features of SMED-SL, one of the patients has an eye phenotype including visual impairment due to optic atrophy. DNA sequencing revealed a novel homozygous dinucleotide deletion mutation (c.2468_2469delCT) on exon 18 of the DDR2 gene in both patients. The mutation resulted in a frameshift leading to an amino acid change at position S823 and a predicted premature termination of translation (p.S823Cfs*2). Subcellular localization of the mutant protein was analyzed in mammalian cell lines, and it was found to be largely retained in the endoplasmic reticulum (ER), which was further supported by its N-glycosylation profile. In keeping with its cellular mis-localization, the mutant protein was found to be deficient in collagen-induced receptor activation, suggesting protein trafficking defects as the major cellular mechanism underlying the loss of DDR2 function in our patients. CONCLUSIONS: Our results indicate that the novel mutation results in defective trafficking of the DDR2 protein leading to loss of function and disease. This confirms our previous findings that DDR2 missense mutations occurring at the kinase domain result in retention of the mutant protein in the ER

PDZD8 Disruption Causes Cognitive Impairment in Humans, Mice, and Fruit Flies.

BACKGROUND: The discovery of coding variants in genes that confer risk of intellectual disability (ID) is an important step toward understanding the pathophysiology of this common developmental disability. METHODS: Homozygosity mapping, whole-exome sequencing, and cosegregation analyses were used to identify gene variants responsible for syndromic ID with autistic features in two independent consanguineous families from the Arabian Peninsula. For in vivo functional studies of the implicated gene's function in cognition, Drosophila melanogaster and mice with targeted interference of the orthologous gene were used. Behavioral, electrophysiological, and structural magnetic resonance imaging analyses were conducted for phenotypic testing. RESULTS: Homozygous premature termination codons in PDZD8, encoding an endoplasmic reticulum-anchored lipid transfer protein, showed cosegregation with syndromic ID in both families. Drosophila melanogaster with knockdown of the PDZD8 ortholog exhibited impaired long-term courtship-based memory. Mice homozygous for a premature termination codon in Pdzd8 exhibited brain structural, hippocampal spatial memory, and synaptic plasticity deficits. CONCLUSIONS: These data demonstrate the involvement of homozygous loss-of-function mutations in PDZD8 in a neurodevelopmental cognitive disorder. Model organisms with manipulation of the orthologous gene replicate aspects of the human phenotype and suggest plausible pathophysiological mechanisms centered on disrupted brain development and synaptic function. These findings are thus consistent with accruing evidence that synaptic defects are a common denominator of ID and other neurodevelopmental conditions