25-Hydroxylase vitamin D deficiency in 27 Saudi Arabian subjects: a clinical and molecular report on CYP2R1 mutations.

Vitamin D deficiency remains a major cause of rickets worldwide. Nutritional factors are the major cause and less commonly, inheritance causes. Recently, CYP2R1 has been reported as a major factor for 25-hydroxylation contributing to the inherited forms of vitamin D deficiency. We conducted a prospective cohort study at King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia, to review cases with 25-hydroxylase deficiency and describe their clinical, biochemical, and molecular genetic features. We analyzed 27 patients from nine different families who presented with low 25-OH vitamin D and not responding to usual treatment. Genetic testing identified two mutations: c.367+1G>A (12/27 patients) and c.768dupT (15/27 patients), where 18 patients were homozygous for their identified mutation and 9 patients were heterozygous. Both groups had similar clinical manifestations ranging in severity, but none of the patients with the heterozygous mutation had hypocalcemic manifestations. Thirteen out of 18 homozygous patients and all the heterozygous patients responded to high doses of vitamin D treatment, but they regressed after decreasing the dose, requiring lifelong therapy. Five out of 18 homozygous patients required calcitriol to improve their biochemical data, whereas none of the heterozygous patients and patients who carried the c.367+1G>A mutation required calcitriol treatment. To date, this is the largest cohort series analyzing CYP2R1-related 25-hydroxylase deficiency worldwide, supporting its major role in 25-hydroxylation of vitamin D. It is suggested that a higher percentage of CYP2R1 mutations might be found in the Saudi population. We believe that our study will help in the diagnosis, treatment, and prevention of similar cases in the future.

Identification of Novel CDH23 Variants Causing Moderate to Profound Progressive Nonsyndromic Hearing Loss.

Mutant alleles of CDH23, a gene that encodes a putative calcium-dependent cell-adhesion glycoprotein with multiple cadherin-like domains, are responsible for both recessive DFNB12 nonsyndromic hearing loss (NSHL) and Usher syndrome 1D (USH1D). The encoded protein cadherin 23 (CDH23) plays a vital role in maintaining normal cochlear and retinal function. The present study's objective was to elucidate the role of DFNB12 allelic variants of CDH23 in Saudi Arabian patients. Four affected offspring of a consanguineous family with autosomal recessive moderate to profound NSHL without any vestibular or retinal dysfunction were investigated for molecular exploration of genes implicated in hearing impairment. Parallel to this study, we illustrate some possible pitfalls that resulted from unexpected allelic heterogeneity during homozygosity mapping due to identifying a shared homozygous region unrelated to the disease locus. Compound heterozygous missense variants (p.(Asp918Asn); p.(Val1670Asp)) in CDH23 were identified in affected patients by exome sequencing. Both the identified missense variants resulted in a substitution of the conserved residues and evaluation by multiple in silico tools predicted their pathogenicity and variable disruption of CDH23 domains. Three-dimensional structure analysis of human CDH23 confirmed that the residue Asp918 is located at a highly conserved DXD peptide motif and is directly involved in "Ca2+" ion contact. In conclusion, our study identifies pathogenic CDH23 variants responsible for isolated moderate to profound NSHL in Saudi patients and further highlights the associated phenotypic variability with a genotypic hierarchy of CDH23 mutations. The current investigation also supports the application of molecular testing in the clinical diagnosis and genetic counseling of hearing loss.

First report of two successive deletions on chromosome 15q13 cytogenetic bands in a boy and girl: additional data to 15q13.3 syndrome with a report of high IQ patient.

15q13.3 syndrome is associated with a wide spectrum of neurological disorders. Among a cohort of 150 neurodevelopmental cases, we identified two patients with two close proximity interstitial hemizygous deletions on chromosome 15q13. Using high-density microarrays, we characterized these deletions and their approximate breakpoints. The second deletion in both patients overlaps in a small area containing CHRNA7 where the gene is partially deleted. The CHRNA7 is considered a strong candidate for the 15q13.3 deletion syndrome's pathogenicity. Patient 1 has cognitive impairment, learning disabilities, hyperactivity and subtle dysmorphic features whereas patient 2 has mild language impairment with speech difficulty, mild dysmorphia, heart defect and interestingly a high IQ that has not been reported in 15q13.3 syndrome patients before. Our study presents first report of such two successive deletions in 15q13.3 syndrome patients and a high IQ in a 15q13.3 syndrome patient. Our study expands the breakpoints and phenotypic features related to 15q13.3 syndrome.

Inclusion of joint laxity, recurrent patellar dislocation, and short distal ulnae as a feature of Van Den Ende-Gupta syndrome: a case report.

BACKGROUND: Van Den Ende-Gupta Syndrome (VDEGS) is an extremely rare autosomal recessive syndrome with less than 20 reported families (approximately 40 patients) in the worldwide literature. CASE PRESENTATION: We have assessed one consanguineous Saudi family with typical features of VDEGS. Two siblings were affected with almost identical features; including blepharophimosis, arachnodactyly, flexion contractures of the elbows, camptodactyly, slender ribs, hooked lateral clavicular ends, and bilateral radial head dislocations. Both patients had several unusual features; including joint laxity, flat feet, recurrent patellar dislocations, and bilateral short distal ulnae. Full sequencing of SCARF2 revealed a homozygous mutation c.773G > A (p. Cys258Tyr) in both affected children. The parents (both with no abnormalities) were heterozygous for the same mutation. CONCLUSION: Joint laxity, recurrent patellar dislocations, and short distal ulnae should be included as part of the clinical spectrum of VDEGS.

GZF1 Mutations Expand the Genetic Heterogeneity of Larsen Syndrome.

Larsen syndrome is characterized by the dislocation of large joints and other less consistent clinical findings. Heterozygous FLNB mutations account for the majority of Larsen syndrome cases, but biallelic mutations in CHST3 and B4GALT7 have been more recently described, thus confirming the existence of recessive forms of the disease. In a multiplex consanguineous Saudi family affected by severe and recurrent large joint dislocation and severe myopia, we identified a homozygous truncating variant in GZF1 through a combined autozygome and exome approach. Independently, the same approach identified a second homozygous truncating GZF1 variant in another multiplex consanguineous family affected by severe myopia, retinal detachment, and milder skeletal involvement. GZF1 encodes GDNF-inducible zinc finger protein 1, a transcription factor of unknown developmental function, which we found to be expressed in the eyes and limbs of developing mice. Global transcriptional profiling of cells from affected individuals revealed a shared pattern of gene dysregulation and significant enrichment of genes encoding matrix proteins, including P3H2, which hints at a potential disease mechanism. Our results suggest that GZF1 mutations cause a phenotype of severe myopia and significant articular involvement not previously described in Larsen syndrome.

Exome sequencing identifies novel NTRK1 mutations in patients with HSAN-IV phenotype.

Hereditary sensory autonomic neuropathy type IV (HSAN-IV) is a rare autosomal recessive disorder that usually begins in infancy and is characterized by anhidrosis, insensitivity to noxious stimuli leading to self-mutilating behavior, and intellectual disability. HSAN-IV is caused by mutations in the neurotrophic tyrosine kinase receptor type 1 gene, NTRK1, encoding the high-affinity receptor of nerve growth factor (NGF) which maps to chromosome 1q21-q22. Patients with HSAN-IV lack all NGF-dependent neurons, the primary afferents and sympathetic postganglionic neurons leading to lack of pain sensation and the presence of anhidrosis, respectively. Herein, we report nine patients from nine unrelated families with HSAN-IV due to various mutations in NTRK1, five of which are novel. These are three missense and two nonsense mutations distributed in various domains of NTRK1 involved in binding of NGF. The affected patients had variable intellectual deficits, and some had delayed diagnosis of HSAN-IV. In addition to being the first report of HSAN-IV from the Arabian Peninsula, this report expands the mutational spectrum of patients with NTRK1 mutations and provides further insights for molecular and clinical diagnosis.

Combined TSC1 and LMX1B mutations in a single patient.

Tuberous sclerosis complex (TSC) and nail-patella syndrome (NPS) are autosomal dominant pleiotropic disorders with full penetrance that can both involve kidneys. TSC1 and NPS genes are located on chromosome 9q3. In a large family with the two disorders with two novel frameshift TSC1 and LMX1B mutations, we describe the phenotypes. The father, who has both disorders, has passed on TSC to three of his children, NPS to another three, and both TSC and NPS to one child. Patients carrying both mutations appear to show an additive phenotype and no obvious epistatic effects. The segregation of two dominant disorders in this family poses a challenge for genetic counseling and indicates the importance of a careful clinical and molecular evaluation for accurate risk assessment.

Long-term outcome of genital reconstruction of Middle Eastern women with congenital adrenal hyperplasia.

OBJECTIVES: There is a paucity of data on the long-term outcome of genital reconstruction of female children with congenital adrenal hyperplasia (CAH) as they become adult women. We report on the surgical outcome general condition and marriage status. MATERIALS AND METHODS: We reviewed the medical records of women 20 years or older with CAH who had genital reconstruction. We interviewed married patients utilizing the female sexual function index (FSFI-6) questionnaire and compared them to age-matched controls. RESULTS: We identified 43 women with CAH with a median age of 24.2 ± 3.9 years and a median follow-up of 23.4 ± 4.6 years. Salt wasting and the severity of virilization affected most patients, parents were commonly cousins, children were reared as boys for a protracted period and surgical reconstruction was usually complex. Only five women had married. Compared with single women, married women had significantly more frequent normal menses, emergency hospital admissions and number of repeated reconstructive surgery. There was no significant difference in FSFI score between patients and controls. Four women conceived and three gave birth to one healthy child. There was no significant difference in the number of children between patients and controls. CONCLUSIONS: CAH has a significant impact on adult women in our region. Most of the patients remain single. Few women get married and these are able to lead a nearly normal sexual life and give birth to healthy children.

A novel X-linked disorder with developmental delay and autistic features.

OBJECTIVE: Genomic duplications that lead to autism and other human diseases are interesting pathological lesions since the underlying mechanism almost certainly involves dosage sensitive genes. We aim to understand a novel genomic disorder with profound phenotypic consequences, most notably global developmental delay, autism, psychosis, and anorexia nervosa. METHODS: We evaluated the affected individuals, all maternally related, using childhood autism rating scale (CARS) and Vineland Adaptive scales, magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) brain, electroencephalography (EEG), electromyography (EMG), muscle biopsy, high-resolution molecular karyotype arrays, Giemsa banding (G-banding) and fluorescent in situ hybridization (FISH) experiments, mitochondrial DNA (mtDNA) sequencing, X-chromosome inactivation study, global gene expression analysis on Epstein-Barr virus (EBV)-transformed lymphoblasts, and quantitative reverse-transcription polymerase chain reaction (qRT-PCR). RESULTS: We have identified a novel Xq12-q13.3 duplication in an extended family. Clinically normal mothers were completely skewed in favor of the normal chromosome X. Global transcriptional profiling of affected individuals and controls revealed significant alterations of genes and pathways in a pattern consistent with previous microarray studies of autism spectrum disorder patients. Moreover, expression analysis revealed copy number-dependent increased messenger RNA (mRNA) levels in affected patients compared to control individuals. A subset of differentially expressed genes was validated using qRT-PCR. INTERPRETATION: Xq12-q13.3 duplication is a novel global developmental delay and autism-predisposing chromosomal aberration; pathogenesis of which may be mediated by increased dosage of genes contained in the duplication, including NLGN3, OPHN1, AR, EFNB1, TAF1, GJB1, and MED12.

Chromosome 12q24.31-q24.33 deletion causes multiple dysmorphic features and developmental delay: First mosaic patient and overview of the phenotype related to 12q24qter defects.

BACKGROUND: Genomic imbalances of the 12q telomere are rare; only a few patients having 12q24.31-q24.33 deletions were reported. Interestingly none of these were mosaic. Although some attempts have been made to establish phenotype/genotype interaction for the deletions in this region, no clear relationship has been established to date. RESULTS: We have clinically screened more than 100 patients with dysmorphic features, mental retardation and normal karyotype using high density oligo array-CGH (aCGH) and identified a ~9.2 Mb hemizygous interstitial deletion at the 12q telomere (Chromosome 12: 46,XY,del(12)(q24.31q24.33) in a severely developmentally retarded patient having dysmorphic features such as low set ears, microcephaly, undescended testicles, bent elbow, kyphoscoliosis, and micropenis. Parents were found to be not carriers. MLPA experiments confirmed the aCGH result. Interphase FISH revealed mosaicism in cultured peripheral blood lymphocytes. CONCLUSIONS: Since conventional G-Banding technique missed the abnormality; this work re-confirms that any child with unexplained developmental delay and systemic involvement should be studied by aCGH techniques. The FISH technique, however, would still be useful to further delineate the research work and identify such rare mosaicism. Among the 52 deleted genes, P2RX2, ULK1, FZD10, RAN, NCOR2 STX2, TESC, FBXW8, and TBX3 are noteworthy since they may have a role in observed phenotype.

Dyggve-Melchior-Clausen syndrome: novel splice mutation with atlanto-axial subluxation.

Dyggve-Melchior-Clausen (DMC) syndrome is a rare autosomal recessive disorder characterized by the association of a progressive spondyloepimetaphyseal dysplasia and mental retardation ranging from mild to severe. The disorder results from mutations in the dymeclin (DYM) gene in the 18q12-12.1 chromosomal region. We report two siblings with classical clinical and radiological features of DMC and asymptomatic atlanto-axial dislocation. A novel homozygous splice-site mutation (IVS15+3G>T) was detected. Reverse transcriptase polymerase chain reaction (RT-PCR) confirmed that this mutation affects normal splicing. To the best of our knowledge, this is the first report of DMC from Saudi Arabia. The splice mutation noted in our patients was compared to the previously reported cases and supports the hypothesis that loss of DYM function is the likely mechanism of disease pathogenesis. In conclusion, distinction between this type of skeletal dysplasia and Morquio disease (MPS IV) is important for paediatricians and clinical geneticist in providing standard patient care and genetic counselling.

Mutations in C2orf37, encoding a nucleolar protein, cause hypogonadism, alopecia, diabetes mellitus, mental retardation, and extrapyramidal syndrome.

Hypogonadism, alopecia, diabetes mellitus, mental retardation, and extrapyramidal syndrome (also referenced as Woodhouse-Sakati syndrome) is a rare autosomal recessive multisystemic disorder. We have identified a founder mutation consisting of a single base-pair deletion in C2orf37 in eight families of Saudi origin. Three other loss-of-function mutations were subsequently discovered in patients of different ethnicities. The gene encodes a nucleolar protein of unknown function, and the cellular phenotype observed in patient lymphoblasts implicates a role for the nucleolus in the pathogenesis of this disease. Our findings expand the list of human disorders linked to the nucleolus and further highlight the developmental and/or maintenance functions of this organelle.

Genome-wide gene expression profiling and mutation analysis of Saudi patients with Canavan disease.

PURPOSE: Canavan disease, caused by a deficiency of aspartoacylase, is one of the most common cerebral degenerative diseases of infancy. The aims of this study were to identify the mutations associated with Canavan disease in Saudi Arabia and to identify differentially expressed genes likely to contribute to the development of this disease. METHODS: Polymerase chain reaction, long polymerase chain reaction, multiplex ligation-dependent probe amplification, sequencing, array comparative genomic hybridization (aCGH), and global gene expression profiling were used to determine putative mutations and likely gene signatures in cultured fibroblasts of patients from Saudi Arabia. RESULTS: One novel and one known large deletion and two previously known mutations (IVS4 + 1G>T and G27R) were identified. Compared with controls, 1440 genes were significantly modulated in Canavan patients (absolute fold change [FC] > or =4). Genome-wide gene expression profiling results indicated that some genes, involved in apoptosis, muscle contraction and development, mitochondrial oxidation, inflammation and glutamate, and aspartate metabolism, were significantly dysregulated. CONCLUSIONS: Our findings indicate that the presence of muscle weakness and hypotonia in patients may be associated with the dysregulated gene activities of cell motility, muscle contraction and development, actin binding, and cytoskeletal-related activities. Overall, these observations are in accordance with previous studies performed in a knockout mouse model.

Pheochromocytoma in children and adolescents: a clinical spectrum.

PURPOSE: The purpose of the study was to identify the spectrum of disease characteristics of pheochromocytoma in children. METHODS: Records of 21 consecutive children diagnosed with pheochromocytoma were reviewed. Patients' age, sex, presentation, associated conditions, diagnostic and imaging modalities used, preoperative preparation, operative details, outcome, and follow-up were recorded. RESULTS: The study included 21 children. Patients were diagnosed clinically and confirmed by biochemical tests. Tumors were localized by imaging studies and all were confirmed pathologically. Patients included 17 with adrenal and 4 with extra-adrenal tumors including 1 in the urinary bladder. Seventeen had sporadic and 4 had familial pheochromocytoma. Associated manifestations were the predominant features in 1 of the 4 patients with familial pheochromocytoma. The patient with bladder pheochromocytoma presented with gross hematuria. Hypertension and visual disturbances were prominent findings in the other patients with sporadic form. Two patients (1 sporadic and 1 familial) had malignant pheochromocytoma. One patient with benign pheochromocytoma had multiple recurrences in chromaffin-containing sites. All patients were treated surgically. Seventeen patients were treated preoperatively with alpha-adrenergic blockade. Two patients continued to have significant visual disturbances. One patient with malignant pheochromocytoma died of the disease, and 1 with recurrent pheochromocytoma had neurologic consequences. CONCLUSIONS: Pheochromocytoma in children has unique characteristics. To our knowledge, this series is one of the largest reports of adrenal pheochromocytoma in children. It also reflects the spectrum of pheochromocytoma in this age group.

Four siblings with distal renal tubular acidosis and nephrocalcinosis, neurobehavioral impairment, short stature, and distinctive facial appearance: a possible new autosomal recessive syndrome.

We report on four siblings (three males, one female) born to first cousin Arab parents with the constellation of distal renal tubular acidosis (RTA), small kidneys, nephrocalcinosis, neurobehavioral impairment, short stature, and distinctive facial features. They presented with early developmental delay with subsequent severe mental, behavioral and social impairment and autistic-like features. Their facial features are unique with prominent cheeks, well-defined philtrum, large bulbous nose, V-shaped upper lip border, full lower lip, open mouth with protruded tongue, and pits on the ear lobule. All had proteinuria, hypercalciuria, hypercalcemia, and normal anion-gap metabolic acidosis. Renal ultrasound examinations revealed small kidneys, with varying degrees of hyperechogenicity and nephrocalcinosis. Additional findings included dilated ventricles and cerebral demyelination on brain imaging studies. Other than distal RTA, common causes of nephrocalcinosis were excluded. The constellation of features in this family currently likely represents a possibly new autosomal recessive syndrome providing further evidence of heterogeneity of nephrocalcinosis syndromes.

Persistent hyperinsulinaemic hypoglycaemia of infancy in 43 children: long-term clinical and surgical follow-up.

OBJECTIVE: To describe the clinical, surgical, biochemical, radiological and electrophysiological features of 43 Saudi children with persistent hyperinsulinaemic hypoglycaemia of infancy (PHHI) who have been followed since 1983. METHODS: Data from 43 patients were retrospectively analysed. PHHI was diagnosed on the basis of high intravenous glucose requirement, high insulin to glucose ratio, negative urinary ketones and normal tandem mass spectrometry. The patients were assessed radiologically by brain magnetic resonance imaging and/or computed tomography and electrophysiologically by brain stem auditory evoked potential, visual evoked response and electroencephalogram. Patients who failed medical therapy received near total pancreatectomy. RESULTS: The patients were severely hypoglycaemic and intolerant to fast. Hypoglycaemic convulsion was the most commonly presenting complaint. Eighteen patients were developmentally delayed and 14 of them had brain atrophy. All patients, except nine, did not respond to medical treatment and underwent surgery. Four pancreatectomized patients developed diabetes and two had malabsorption. One baby had 180 cm resection of gangrenous bowel most likely secondary to octreotide. No common bile duct injury was encountered. One patient was treated medically during childhood and developed diabetes and gained weight during adolescence. CONCLUSION: PHHI is a relatively common and serious disease among Saudi children. Early intervention is necessary to avoid neurological damage in patients who are severely hypoglycaemic and unresponsive to medical therapy. Surgically and probably medically treated patients are at a high risk of developing diabetes, which could be the natural outcome of this disease. Care and spending time during surgery to visualize the common bile duct help in avoiding its injury.