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Background Biotin–thiamine‐responsive basal ganglia disease (BTBGD) is an autosomal recessive neurometabolic disorder mostly presented in children. The disorder is described as having subacute encephalopathy with confusion, dystonia, and dysarthria triggered by febrile illness that leads to neuroregression and death if untreated. Using biotin and thiamine at an early stage of the disease can lead to significant improvement. Methods BTBGD is a treatable disease if diagnosed at an early age and has been frequently reported in Saudi population. Keeping this in mind, the current study screened 3000 Saudi newborns for the SLC19A3 gene mutations using target sequencing, aiming to determine the carrier frequency in Saudi Population and whether BTBGD is a good candidate to be included in the newborn‐screened disorders. Results Using targeted gene sequencing, DNA from 3000 newborns Saudi was screened for the SLC19A3 gene mutations using standard methods. Screening of the SLC19A3 gene revealed a previously reported heterozygous missense mutation (c.1264A>G (p.Thr422Ala) in six unrelated newborns. No probands having homozygous pathogenic mutations were found in the studied cohort. The variant has been frequently reported previously in homozygous state in Saudi population, making it a hot spot mutation. The current study showed that the carrier frequency of SLC19A3 gene mutation is 1 of 500 in Saudi newborns. Conclusion For the first time in the literature, we determined the carrier frequency of SLC19A3 gene mutation in Saudi population. The estimated prevalence is too rare in Saudi population (at least one in million); therefore, the data are not in favor of including such very rare disorders in newborn screening program at population level. However, a larger cohort is needed for a more accurate estimate.

Abstract Context Congenital hypothyroidism (CH) is the most common neonatal endocrine disorder, affecting one in 3000 to 4000 newborns. Since the introduction of a newborn screening program in 1988, more than 300 cases have been identified. The underlying genetic defects have not been systematically studied. Objective To identify the mutation spectrum of CH-causing genes. Methods Fifty-five patients from 47 families were studied by next-generation exome sequencing. Results Mutations were identified in 52.7% of patients (29 of 55) in the following 11 genes: TG, TPO, DUOX2, SLC26A4, SLC26A7, TSHB, TSHR, NKX2-1, PAX8, CDCA8, and HOXB3. Among 30 patients with thyroid dyshormonogenesis, biallelic TG mutations were found in 12 patients (40%), followed by biallelic mutations in TPO (6.7%), SLC26A7 (6.7%), and DUOX2 (3.3%). Monoallelic SLC26A4 mutations were found in two patients, one of them coexisting with two tandem biallelic deletions in SLC26A7. In 25 patients with thyroid dysgenesis, biallelic mutations in TSHR were found in six patients (24%). Biallelic mutations in TSHB, PAX 8, NKX2-1, or HOXB3 were found once in four different patients. A monoallelic CDCA8 mutation was found in one patient. Most mutations were novel, including three TG, two TSHR, and one each in DUOX2, TPO, SLC26A7, TSHB, NKX2-1, PAX8, CDCA8, and HOXB3. SLC26A7 and HOXB3 were novel genes associated with thyroid dyshormonogenesis and dysgenesis, respectively. Conclusions TG and TSHR mutations are the most common genetic defects in Saudi patients with CH. The prevalence of other disease-causing mutations is low, reflecting the consanguineous nature of the population. SLC26A7 mutations appear to be associated with thyroid dyshormonogenesis. The mutation spectrum was analyzed by NGS in 55 Saudi patients with CH. The most common mutations were TG and TSHR. SLC26A7 appears to be associated with thyroid hormone synthesis.

Background Pathogenic variants in SPTBN4 have been linked to autosomal recessive “neurodevelopmental disorder with hypotonia, neuropathy, and deafness” (MIM# 617519) known as NEDHND. The disorder is highlighted with neuropathy, muscle weakness, and infrequent appearance of seizures in the affected individuals. This study aims to investigate the natural history of the disease, present genetic and clinical appearance of the syndrome in a highly consanguineous population, Saudi Arabia, and finally provide an overview of the reported cases, their clinical features, and disease-causing variants. Methods The study started with a search through neurology clinics and local databases and utilized genetic testing records after diagnosing a patient with NEDHND at our hospital (King Faisal Specialist Hospital and Research Centre, KFSHRC). Based on the search we have identified additional patients (in total, n  = 10) with the disease and performed genetic testing using whole exome sequencing and confirmatory Sanger sequencing. We performed RT-PCR on RNA extracted from lymphoblastoid cell line from a patient who found to have an aberrant splicing variant. Finally, we comprehensively reviewed current literature and available data related to the disease. Results We present natural history of SPTBN4-associated neurodevelopmental disorder with hypotonia, neuropathy, and deafness in addition to four Saudi families with ten affected individuals who share clinical features of NEDHND. We report three known mutations and one novel nonsense variant, highlight atypical clinical features related to cerebellar involvement, confirm the pathogenicity of a splicing variant by RT-PCR, and review the findings of previously reported patients. Conclusion Our study defines the clinical phenotype of a cohort of NEDHND in detail including the evolution of patients’ clinical features, compares them to previously reported cases, and utilizes the existing data on the disease to direct development of a better prevention plan by means of genetic and preimplantation counseling. Our study may help and enable future clinical trials focusing on NEDHND in our country.

A simple and efficient validated assay for quantifying 21‐deoxycortisol (21‐DOC), 17‐hydroxyprogesterone (17‐OHP), cortisol, and cortisone in human plasma has been developed using ultra‐high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC‐MS/MS). Analysis of plasma samples were performed on Atlantis dC18 (3  μ m) column using a mobile phase of 20.0 mM ammonium acetate and acetonitrile (50:50, v : v ) that was delivered at isocratic flow rate 0.3 mL/minute. After addition of d4‐cortisol as an internal standard (IS), plasma samples containing 21‐DOC, 17‐OHP, cortisol, and cortisone were extracted with mixture of dichloromethane and tert‐butylmethyl ether 1:2 ( v / v ). Analytes were detected and quantified in the positive ion mode of electrospray ionization using multiple reaction monitoring transition set at mass to charge (m/z): 347.17 ⟶ 311.12, 331.17 ⟶ 96.97, 363.11 ⟶ 121.00, 361.18 ⟶ 163.11, and 367.19 ⟶ 121.24 for 21‐DOC and 17‐OHP, cortisol, cortisone, and cortisol‐d4 (IS), respectively. The relationship between concentration and peak area response (analyte/IS) were linear over the range of 0.25–50, 0.5–100, 1–200, and 2–400 ng/mL for 21‐DOC, 17‐OHP, cortisone, and cortisol, respectively. The mean extraction recovery of the analytes was in the range of 83%–96%. The coefficient of variation within and between days was less than 13.6%, and the bias ranged from −9.2% to 12%. The measured level of cortisol, cortisone, and 17‐OHP was in the range of 21.9–110, 4.33–12.71, and 0.37–1.4 ng/mL, respectively. Furthermore, the measured value of cortisone–cortisol ratio was in the range of 0.08–0.21.

Medium-chain acyl-CoA dehydrogenase deficiency (MCADD), caused by mutated ACADM gene, is a potentially fatal fatty acid oxidation defect. Detection of MCADD is now part of tandem mass spectrometry (MS-MS)-based newborn screening programs worldwide. To date, more than 67 mutations have been reported to cause MCADD with a single allele, c.985A>G, being the most common in patients of northwestern European descent. In Saudi Arabia, the Newborn Screening Program, officially launched in 2005, screens for 16 disorders including MCADD. Over a period of 3 years, 237,812 newborns were screened; 13 were identified to have MCADD giving an incidence of 1:18,293. Since the introduction of MS-MS to our institution, however, a total of 30 patients were detected to have MCADD. These cases were either newborns, at high-risk family members, or clinically suspected. The C8-carnitine levels (median 3.31, range 0.81–16.33 µM) were clearly diagnostic in all analyzed samples. Sequencing ACADM in 20 DBS revealed two novel mutations: c.362C>T (p.T121I) and c.347G>A (p.C116Y) substitutions, neither of which were detected in 300 chromosomes from controls. Eighteen (90%) patients were homozygous for the T121I mutation and two (10%) were compound heterozygous (T121I/C116Y). Our molecular data lend further support to MS-MS biochemical screening for MCADD and provide evidence for the relatively high incidence of MCADD in the Arab population. The identification of a founder mutation for MCADD has important implications for the preventive screening programs not only in Saudi Arabia but potentially also in other countries in the region.

Background β2-adrenoceptor (β2AR) gene polymorphism glutamine 27 glutamic acid (Gln27Glu) and Arg16Gly were reported to have an association with obesity and obesity related disorders in some population. We evaluated Gln27Glu polymorphism in the β2AR gene in obese Saudi populations to investigate the association of β2AR gene with obesity and other related metabolic parameters. Design We studied possible association of Gln27Glu in β2AR gene with body mass index (BMI), anthropometric measurements and other metabolic parameters. The β2AR gene polymorphism (Gln27Glu) was identified by sequencing PCR products representing locus of interest. Based on BMI, the subjects were divided into three groups, normal weight, overweight and obese. The genotype and allele frequency were calculated separately for each group. Results The allelic frequency of Glu27 did not differ amongst the three groups, though the Glu27 homozygote (Glu/Glu) were more in obese subjects and had higher concentration of triglyceride, leptin and insulin compared to in the Gln27 heterozygotes and Gln/Gln homozygotes. Conclusions In this study we were able to provide evidence on the influence of Gln27Glu genetic variant of β2AR gene on lipid phenotypes, insulin and leptin levels in the Saudi populations.

Objective. To assess the attitude and knowledge of the Saudi mothers toward newborn screening (NBS) program. Methods. A total of 425 Saudi women (only mothers who have at least one pregnancy) participated in the study from different regions in Saudi Arabia and completed the structured questionnaire which sought their views on the NBS services. Results. A majority of the participating women (91.1%) supported the NBS program and felt it was very important and useful. However, knowledge of NBS was found to be very limited and only 34.6% knew that NBS was a test to detect genetic disorders. A lack of communication and counseling to NBS clients by health authorities offering screening is implied. Conclusion. In general, there is a positive attitude towards the NBS program among Saudi women. However, they have several concerns to improve the availability of medication and formulas, genetic counseling, medical interventions, communication, education materials, and awareness.

In this paper, we address the preventive health aspects of genetic problems in the Middle East and provide guidelines to prioritize preventive strategies. Applications of various novel genetic techniques such as comprehensive neonatal screening, high throughput heterozygote detection, preimplantation genetic diagnosis, Affymetrix systems, the NanoChip system and a new way of sensitive karyotyping for single-cell chromosome abnormalities are discussed. In conclusion, from the various genetic techniques available, each country should adopt strategies most suitable to its genetic needs and should prioritize the programs to be used in prevention.

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.

Rachel Freathy and colleagues report results of a large-scale genome-wide association study of birth weight. They identify four loci newly associated with this trait and find overlap between birth weight–associated loci and those influencing adult height and metabolism. Birth weight within the normal range is associated with a variety of adult-onset diseases, but the mechanisms behind these associations are poorly understood 1 . Previous genome-wide association studies of birth weight identified a variant in the ADCY5 gene associated both with birth weight and type 2 diabetes and a second variant, near CCNL1 , with no obvious link to adult traits 2 . In an expanded genome-wide association meta-analysis and follow-up study of birth weight (of up to 69,308 individuals of European descent from 43 studies), we have now extended the number of loci associated at genome-wide significance to 7, accounting for a similar proportion of variance as maternal smoking. Five of the loci are known to be associated with other phenotypes: ADCY5 and CDKAL1 with type 2 diabetes, ADRB1 with adult blood pressure and HMGA2 and LCORL with adult height. Our findings highlight genetic links between fetal growth and postnatal growth and metabolism.