Zellweger syndrome; identification of mutations in and gene in Saudi families.

Background: Peroxisome biogenesis disorders (PBD) affect multiple organ systems. It is characterized by neurological dysfunction, hypotonia, ocular anomalies, craniofacial abnormalities, and absence of peroxisomes in fibroblasts. PBDs are associated with mutations in any of fourteen different genes, which are involved in peroxisome biogenesis.

Biallelic Variant in the AGXT Gene in a Family Segregating Primary Hyperoxaluria; Accurate Genetic Diagnosis and Carrier Detection.

Aim: Autosomal recessive primary hyperoxalurias (PH) are genetic disorders characterised by elevated oxalate production. Mutations in genes involved in glycoxylate metabolism are the underlying cause of PH. Type 1 PH (PH1) results in malfunctioning of alanine-glyoxylate aminotransferase enzymes of liver due to a change in the genetic sequence of alanine-glyoxylate aminotransferase (AGXT) gene.

Biallelic Loss of Function Variant in SEC31A Is Associated With Lethal Neurodevelopmental Disorder, Dysmorphic Features, and Skeletal Defects.

Biallelic loss of function variant in SEC31A is associated with lethal neurodevelopmental disorder, dysmorphic features, and skeletal defects.

Exome sequence analysis identifies a homozygous, pathogenic, frameshift variant in the gene underlying clinical variant of α-mannosidosis.

Background: α-mannosidosis (MAN) is a rare genetic condition that segregates in an autosomal recessive manner. Lack of lysosomal alpha-mannosidase is the underlying cause of the disease. Symptoms of the disease gradually worsen with the age.

Exome Sequence Analysis to Characterize Undiagnosed Family Segregating Motor Impairment and Dystonia.

: Hypermanganesemia with dystonia 1 (HMNDYT1) is a rare genetic disorder characterized by elevated blood manganese levels. This condition is associated with polycythemia, motor neurodegeneration with extrapyramidal features, and hepatic dysfunction, which can progress to cirrhosis in some patients. : In this study, a consanguineous Saudi family with two affected individuals exhibiting symptoms of severe motor impairment, spastic paraparesis, postural instability, and dystonia was studied.

Identification of Novel and Recurrent Variants in , , and Genes in Families with Metabolic Disorders in Saudi Arabia.

Inherited metabolic disorders (IMDs) are a group of genetic disorders characterized by defects in enzymes or transport proteins involved in metabolic processes. These defects result in an abnormal accumulation of metabolites and thus interfere with the body's metabolism. A variety of IMDs exist and differential diagnosis is often challenging.

Loss-of-function variant in spermidine/spermine N1-acetyl transferase like 1 (SATL1) gene as an underlying cause of autism spectrum disorder.

Autism spectrum disorder (ASD) is a complicated, lifelong neurodevelopmental disorder affecting verbal and non-verbal communication and social interactions. ASD signs and symptoms appear early in development before the age of 3 years. It is unlikely for a person to acquire autism after a period of normal development.

Biallelic variants in HECT E3 paralogs, HECTD4 and UBE3C, encoding ubiquitin ligases cause neurodevelopmental disorders that overlap with Angelman syndrome.

Purpose: Pathogenic variants in genes encoding ubiquitin E3 ligases are known to cause neurodevelopmental syndromes. Additional neurodevelopmental disorders associated with the other genes encoding E3 ligases are yet to be identified.

Methods: Chromosomal analysis and exome sequencing were used to identify the genetic causes in 10 patients from 7 unrelated families with syndromic neurodevelopmental, seizure, and movement disorders and neurobehavioral phenotypes.

NPHP3 splice acceptor site variant is associated with infantile nephronophthisis and asphyxiating thoracic dystrophy; A rare combination.

Nephronophthisis (NPHP) is a group of rare inherited ciliopathy disorders characterized by the multicystic dysplastic kidney, oligohydramnios, and tubulointerstitial nephritis that progresses to end-stage renal disease (ESRD). NPHP is a clinically and genetically heterogeneous disorder with extrarenal symptoms including skeletal deformities, nervous system anomalies, and ophthalmologic features. Three clinical subtypes, infantile, juvenile, and adolescent, have been recognized based on age of onset of ESRD.

Further Evidence of a Recessive Variant in as an Underlying Cause of Ehlers-Danlos Syndrome: A Report of a Saudi Founder Mutation.

Ehlers-Danlos syndrome (EDS) is a group of clinically and genetically heterogeneous disorder of soft connective tissues. The hallmark clinical features of the EDS are hyperextensible skin, hypermobile joints, and fragile vessels. It exhibits associated symptoms including contractures of muscles, kyphoscoliosis, spondylodysplasia, dermatosparaxis, periodontitis, and arthrochalasia.

A Novel Frameshift Mutation in the ITGB3 Gene Leading to Glanzmann's Thrombasthenia in a Saudi Arabian Family.

Glanzmann's thrombasthenia (GT) is an autosomal recessive congenital bleeding disorder of platelet aggregation. Mutations in ITGA2B and ITGB3 genes result in quantitative and/or qualitative abnormalities of the glycoprotein receptor complex IIb/IIIa (integrin αIIbβ3), which in turn impairs platelet aggregation and lead to GT. In this study, whole genome single nucleotide polymorphism (SNP) genotyping as well as whole exome sequencing was performed in a large family segregating GT.

Biallelic loss of function variant in the unfolded protein response gene PDIA6 is associated with asphyxiating thoracic dystrophy and neonatal-onset diabetes.

Protein disulfide isomerase A6 (PDIA6) is an unfolded protein response (UPR)-regulating protein. PDIA6 regulates the UPR sensing proteins, Inositol requiring enzyme 1, and EIF2AK3. Biallelic inactivation of the two genes in mice and humans resulted in embryonic lethality, diabetes, skeletal defects, and renal insufficiency.

A novel missense variant in the gene in patients with moderate to severe bleeding disorder.

Inherited platelet function disorder-18 (IPD-18) is a relatively new non-syndromic autosomal recessive bleeding disorder. It is characterized by deficient or dysfunctional CalDAG-GEFI protein. The distinctive feature of the disease is impaired platelet aggregation in response to multiple physiologic agonists.

Homozygosity mapping and whole exome sequencing provide exact diagnosis of Cohen syndrome in a Saudi family.

Background: Cohen syndrome (CS) is a rare multi-system autosomal recessive disorder with a high prevalence in the Finnish population. Clinical features of Finnish-type CS are homogeneous, however, in non-Finnish populations, CS diagnosis is challenging due to broad phenotypic variability.

Methods: We studied a consanguineous family having three affected individuals with clinical features of severe intellectual disability and global developmental delay.

A homozygous missense variant in the homeobox domain of the NKX6-2 results in progressive spastic ataxia type 8 associated with lower limb weakness and neurological manifestations.

Background: Progressive spastic ataxia is a heterogeneous disorder characterized by cerebellar ataxia and limb spasticity associated with other severe neurological complications. Spastic ataxia is classified into pure and complex types, inherited in both an autosomal recessive and autosomal dominant manner. It is caused by pathogenic variants in at least eight different genes, including NKX6-2 (MIM 607063) located on chromosome 10q26.

Centromere protein I (CENPI) is a candidate gene for X-linked steroid sensitive nephrotic syndrome.

Background: Individuals with proteinuria in association with hypoalbuminemia, edema, and hyperlipidemia are considered as having nephrotic syndrome (NS). NS is the most common kidney disease seen in the paediatric age group. NS is usually classified into steroid resistant nephrotic syndrome (SRNS) and steroid sensitive nephrotic syndrome (SSNS).

Novel homozygous loss-of-function mutations in and genes in retinitis pigmentosa patients.

: Retinitis pigmentosa (RP) is a heterogeneous group of ocular dystrophy. It is challenging to identify the underlying genetic defect in individuals with RP due to huge genetic heterogeneity. This study was designed to delineate the genetic defect(s) underlying RP in extended Saudi families and to describe the possible disease mechanism.

A Heterozygous Mutation in the Triple Helical Region of the Alpha 1 (II) Chain of the COL2A1 Protein Causes Non-Lethal Spondyloepiphyseal Dysplasia Congenita.

Heterozygous pathogenic variants in the gene result in several clinical features including impaired skeletal growth, ocular and otolaryngological abnormalities. Missense mutations in the triple helical region of the COL2A1 protein have been associated with lethal spondyloepiphyseal dysplasia (SED). In this study, we aimed to identify the underlying cause of a case of SED congenita (SEDC) in a 27-month-old child.

NR2F1 mediated down-regulation of osteoblast differentiation was rescued by bone morphogenetic protein-2 (BMP-2) in human MSC.

Endochondral ossification is the process by which long bones are formed; the process of long bone formation is regulated by numerous factors such as transcription factors, cytokines, and extracellular matrix molecules. Human hormone Nuclear receptors (hHNR) are a family of ligand-regulated transcription factors that are activated by steroid hormones, such as estrogen and progesterone, and various lipid-soluble signals, including retinoic acid, oxysterols, and thyroid hormone. Whole genome microarray data from our previous study revealed that most hHNR's are up-regulated during osteoblast differentiation in hMSCS.

Whole exome sequencing identification of a novel insertion mutation in the phospholipase C ε‑1 gene in a family with steroid resistant inherited nephrotic syndrome.

Nephrotic syndrome (NS) represents a heterogeneous group of kidney disorders characterized by excessive proteinuria, hypoalbuminemia and edema. Defects in the filtration barrier of the glomeruli results in the development of NS. The genetic cause of NS remains to be fully elucidated.

An 18 bps in-frame deletion mutation in RUNX2 gene is a population polymorphism rather than a pathogenic variant.

We recruited a family with an affected child exhibiting features of cleidocranial dysplasia with some phenotypic variations from reported cases. Whole exome sequencing data analysis identified an 18-bps heterozygous in-frame deletion variant (c.243-260delGGCGGCTGCGGCGGCGGC) in the RUNX2 gene.

TGF1-Induced Differentiation of Human Bone Marrow-Derived MSCs Is Mediated by Changes to the Actin Cytoskeleton.

TGF is a potent regulator of several biological functions in many cell types, but its role in the differentiation of human bone marrow-derived skeletal stem cells (hMSCs) is currently poorly understood. In the present study, we demonstrate that a single dose of TGF1 prior to induction of osteogenic or adipogenic differentiation results in increased mineralized matrix or increased numbers of lipid-filled mature adipocytes, respectively. To identify the mechanisms underlying this TGF-mediated enhancement of lineage commitment, we compared the gene expression profiles of TGF1-treated hMSC cultures using DNA microarrays.

Whole exome sequencing identified a novel single base pair insertion mutation in the EYS gene in a six generation family with retinitis pigmentosa.

Retinitis pigmentosa (RP) is a group of inherited progressive retinal dystrophies (RD) and is characterized by photoreceptor degeneration. RP is clinically and genetically heterogeneous disorder. More than 70 genes are known and, thus, identification of causative genes and mutations in known genes is challenging.