Genetic variants in components of the NALCN-UNC80-UNC79 ion channel complex cause a broad clinical phenotype (NALCN channelopathies).

NALCN is a conserved cation channel, which conducts a permanent sodium leak current and regulates resting membrane potential and neuronal excitability. It is part of a large ion channel complex, the "NALCN channelosome", consisting of multiple proteins including UNC80 and UNC79. The predominant neuronal expression pattern and its function suggest an important role in neuronal function and disease. So far, biallelic NALCN and UNC80 variants have been described in a small number of individuals leading to infantile hypotonia, psychomotor retardation, and characteristic facies 1 (IHPRF1, OMIM 615419) and 2 (IHPRF2, OMIM 616801), respectively. Heterozygous de novo NALCN missense variants in the S5/S6 pore-forming segments lead to congenital contractures of the limbs and face, hypotonia, and developmental delay (CLIFAHDD, OMIM 616266) with some clinical overlap. In this study, we present detailed clinical information of 16 novel individuals with biallelic NALCN variants, 1 individual with a heterozygous de novo NALCN missense variant and an interesting clinical phenotype without contractures, and 12 individuals with biallelic UNC80 variants. We report for the first time a missense NALCN variant located in the predicted S6 pore-forming unit inherited in an autosomal-recessive manner leading to mild IHPRF1. We show evidence of clinical variability, especially among IHPRF1-affected individuals, and discuss differences between the IHPRF1- and IHPRF2 phenotypes. In summary, we provide a comprehensive overview of IHPRF1 and IHPRF2 phenotypes based on the largest cohort of individuals reported so far and provide additional insights into the clinical phenotypes of these neurodevelopmental diseases to help improve counseling of affected families.

Mutation of TBCE causes hypoparathyroidism-retardation-dysmorphism and autosomal recessive Kenny-Caffey syndrome.

The syndrome of congenital hypoparathyroidism, mental retardation, facial dysmorphism and extreme growth failure (HRD or Sanjad-Sakati syndrome; OMIM 241410) is an autosomal recessive disorder reported almost exclusively in Middle Eastern populations. A similar syndrome with the additional features of osteosclerosis and recurrent bacterial infections has been classified as autosomal recessive Kenny-Caffey syndrome (AR-KCS; OMIM 244460). Both traits have previously been mapped to chromosome 1q43-44 (refs 5,6) and, despite the observed clinical variability, share an ancestral haplotype, suggesting a common founder mutation. We describe refinement of the critical region to an interval of roughly 230 kb and identification of deletion and truncation mutations of TBCE in affected individuals. The gene TBCE encodes one of several chaperone proteins required for the proper folding of alpha-tubulin subunits and the formation of alpha-beta-tubulin heterodimers. Analysis of diseased fibroblasts and lymphoblastoid cells showed lower microtubule density at the microtubule-organizing center (MTOC) and perturbed microtubule polarity in diseased cells. Immunofluorescence and ultrastructural studies showed disturbances in subcellular organelles that require microtubules for membrane trafficking, such as the Golgi and late endosomal compartments. These findings demonstrate that HRD and AR-KCS are chaperone diseases caused by a genetic defect in the tubulin assembly pathway, and establish a potential connection between tubulin physiology and the development of the parathyroid.

Practical guidelines addressing ethical issues pertaining to the curation of human locus-specific variation databases (LSDBs).

More than 1,000 Web-based locus-specific variation databases (LSDBs) are listed on the Website of the Human Genetic Variation Society (HGVS). These individual efforts, which often relate phenotype to genotype, are a valuable source of information for clinicians, patients, and their families, as well as for basic research. The initiators of the Human Variome Project recently recognized that having access to some of the immense resources of unpublished information already present in diagnostic laboratories would provide critical data to help manage genetic disorders. However, there are significant ethical issues involved in sharing these data worldwide. An international working group presents second-generation guidelines addressing ethical issues relating to the curation of human LSDBs that provide information via a Web-based interface. It is intended that these should help current and future curators and may also inform the future decisions of ethics committees and legislators. These guidelines have been reviewed by the Ethics Committee of the Human Genome Organization (HUGO).

Peripheral venous route for administration of ammonul infusion for treatment of acute hyperammonemia. An experience from a tertiary center in Saudi Arabia.

OBJECTIVES: To determine the local effects of peripheral Ammonul infusion on the skin and the subcutaneous tissues.  Methods: This retrospective study was conducted at Prince Sultan Military Medical City, Riyadh, Saudi Arabia. All children less than 16 years of age admitted between December 2015 and October 2018 with hyperammonemia and received Ammonul infusion for treatment were recruited. Results: Twenty-one patients received the Ammonul infusion. They were admitted 58 times with acute hyperammonemia during the study period, with an average of 2.8 admissions per patient. The mean age of the included patients was 49.5 months. The most frequent underlying diagnoses were propionic acidemia (n=9), urea cycle disorders (n=5), and intrinsic liver disease (n=3). All participants received Ammonul through peripheral lines except 3 who received it through central lines. No extravasation, burns, or other local side effects were observed in this cohort. CONCLUSION: This data indicate that the use of Ammonul through a peripheral venous route appears to be safe and not associated with infusion-related local adverse effects.

Fructose-1,6-bisphosphatase deficiency with confirmed molecular diagnosis. An important cause of hypoglycemia in children.

OBJECTIVES: To draw attention towards fructose-1,6-bisphosphatase (FBPase) deficiency as an important cause of hypoglycemia and lactic acidosis and to implement preventive strategies. Methods: This observational, cross-sectional study was conducted on 7 Saudi patients with genetically confirmed FBPase deficiency from 2008 to 2018 at Prince Sultan Military Medical City, Riyadh, Saudi Arabia. Results: Participants ranged in age from 1-10 years, and all presented with recurrent hypoglycemia. All but one had associated severe metabolic acidosis, and 3 patients (42.9%) presented with hypoglycemia and severe acidosis since birth. The mean duration from presentation to diagnosis was 39.4 months, as other diagnoses, like glycogen storage diseases and mitochondrial diseases needed to be ruled out. Development was normal apart from speech delay in one patient with a novel variant of the FBP1 gene. All patients have homozygous variants in the FBP1 gene.  Conclusion: Fructose-1,6-bisphosphatase is an important cause of hypoglycemia and acidosis; therefore, it is important to offer early molecular diagnostics in any child presenting with these symptoms. Molecular diagnostics should always be undertaken to confirm the diagnosis and for further preventive strategies.

Incidence of newborn screening disorders among 56632 infants in Central Saudi Arabia. A 6-year study.

OBJECTIVES: To determine the incidence of newborn screening (NBS) disorders and to study the key performance indicators of the program. METHODS: This retrospective single-center study enrolled all infants who underwent NBS from January 2012 to December 2017 at Prince Sultan Military Medical City, Riyadh, Saudi Arabia. We screened 17 NBS disorders. Blood samples were collected 24 hours after birth. If the initial result was positive, a second sample was collected. True positive cases were immediately referred for medical management. Data were extracted from laboratory computerized and non-computerized records using case report forms. RESULTS: During the study period, 56632 infants underwent NBS with a coverage rate of 100%. Thirty-eight cases were confirmed. The incidence of congenital hypothyroidism was 1:3775. The positive predictive value for the detection of congenital hypothyroidism was 11.8%. Propionic aciduria was the most common metabolic disorder, with an incidence of 1:14158. Very long-chain acyl CoA dehydrogenase deficiency and glutaric aciduria type 1 had an incidence of 1:18877 each. Phenylketonuria, biotinidase deficiency, maple syrup urine disease, and citrullinemia had an incidence of 1:28316 each. However, galactosemia and 3-methyl crotonyl carboxylase deficiency had the lowest incidence of 1:56632. CONCLUSION: The NBS coverage rate at our facility was 100%. Congenital hypothyroidism was the most frequently detected disorder with an incidence that matches worldwide figures. The incidence of other inherited disorders was consistent with regional figures.

Planning the human variome project: the Spain report.

The remarkable progress in characterizing the human genome sequence, exemplified by the Human Genome Project and the HapMap Consortium, has led to the perception that knowledge and the tools (e.g., microarrays) are sufficient for many if not most biomedical research efforts. A large amount of data from diverse studies proves this perception inaccurate at best, and at worst, an impediment for further efforts to characterize the variation in the human genome. Because variation in genotype and environment are the fundamental basis to understand phenotypic variability and heritability at the population level, identifying the range of human genetic variation is crucial to the development of personalized nutrition and medicine. The Human Variome Project (HVP; http://www.humanvariomeproject.org/) was proposed initially to systematically collect mutations that cause human disease and create a cyber infrastructure to link locus specific databases (LSDB). We report here the discussions and recommendations from the 2008 HVP planning meeting held in San Feliu de Guixols, Spain, in May 2008.

Capturing all disease-causing mutations for clinical and research use: toward an effortless system for the Human Variome Project.

The collection of genetic variants that cause inherited disease (causative mutation) has occurred for decades albeit in an ad hoc way, for research and clinical purposes. More recently, the access to collections of mutations causing specific diseases has become essential for appropriate genetic health care. Because information has accumulated, it has become apparent that there are many gaps in our ability to correctly annotate all the changes that are being identified at ever increasing rates. The Human Variome Project (www.humanvariomeproject.org) was initiated to facilitate integrated and systematic collection and access to this data. This manuscript discusses how collection of such data may be facilitated through new software and strategies in the clinical genetics and diagnostic laboratory communities.

Al-Aqeel Sewairi syndrome, a new autosomal recessive disorder with multicentric osteolysis, nodulosis and arthropathy. The first genetic defect of matrix metalloproteinase 2 gene.

OBJECTIVE: We report a distinctive autosomal recessive multicentric osteolysis in Saudi Arabian families with distal arthropathy of the metacarpal, metatarsal and interphalangeal joints, with ultimate progression to the proximal joints with decreased range of movements and deformities with ankylosis and generalized osteopenia. In addition, they had large, painful to touch palmar and plantar pads. Hirsutism and mild dysmorphic facial features including proptosis, a narrow nasal bridge, bulbous nose and micrognathia. METHODS: Using a genome-wide search for microsatellite markers from 11 members of the family from the Armed Forces Hospital and King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia, localized the disease gene to chromosome 16q12-21. Haplotype analysis with additional markers narrowed the critical region to 1.2cM and identified the matrix metalloproteinase 2 (MMP-2), (gelatinase A, collagenase type IV, EC 3.4, 24,24) gene as a disease candidate at Mount Sinai School of Medicine, New York, United States of America in April 2000. RESULTS: Some affected individuals were homoallelic for a nonsense mutation (TCA>TAA) in codon 244 of exon 5, predicting the replacement of a tyrosine residue by a stop codon in the first fibronectin type II domain (Y244X). Other affected members had a missense mutation in exon 2 arginine 101-histidine (R101H) leading to no MMP-2 enzyme activity in serum or fibroblast or both of affected individuals. In other affected members, a non-pathogenic homoallelic GT transversion resulted in the substitution of an aspartate with a tyrosine residue in codon 210 of exon 4 (D210Y). The MMP-2-null mouse has no developmental defects, but are small, which may reflect genetic redundancy. CONCLUSION: The discovery that deficiency of this well-characterized gelatinase/collagenase results in an inherited form of an osteolytic and arthritic disorder provides an invaluable insights for the understanding of osteolysis and arthritis and is the first genetic evidence that MMP2 deficiency is important in growth and development.

Identification of a novel IVD mutation in a consanguineous family with isovaleric acidemia.

Isovaleric acidemia (IVA) is a rare autosomal recessive disorder caused by a deficiency of isovaleryl-CoA dehydrogenase encoded by IVD gene. In this case study we report the first Saudi IVA patients from a consanguineous family with a novel transversion (p.G362V) and briefly discuss likely phenotype-genotype correlation of the disease in the Saudi population. We explored the functional consequences of the mutation by using various bioinformatics prediction algorithms and discussed the likely mechanism of the disease caused by the mutation.

Human cloning, stem cell research. An Islamic perspective.

The rapidly changing technologies that involve human subjects raise complex ethical, legal, social, and religious issues. Recent advances in the field of cloning and stem cell research have introduced new hopes for the treatment of serious diseases. But this promise has raised many complex questions. This field causes debate and challenge, not only among scientists but also among ethicists, religious scholars, governments, and politicians. There is no consensus on the morality of human cloning, even within specific religious traditions. In countries in which religion has a strong influence on political decision making, the moral status of the human embryo is at the center of the debate. Because of the inevitable consequences of reproductive cloning, it is prohibited in Islam. However, stem cell research for therapeutic purposes is permissible with full consideration, and all possible precautions in the pre-ensoulment stages of early fetus development, if the source is legitimate.

Preimplantation genetic diagnosis of Morquio disease.

OBJECTIVES: Morquio syndrome is an autosomal recessive disease and mutations in the N-acetylgalactosamine 6-sulfate sulfatase (GALNS) gene cause Morquio type A disease. Preimplantation genetic diagnosis (PGD), an early form of prenatal diagnosis for couples at risk of transmitting inherited diseases, was applied to prevent transmission of this disease. METHODS: A couple with three affected children, having homozygous W159C (p. Trp 159 Cys) mutation in GALNS gene, underwent in vitro fertilization (IVF) treatment and PGD. Mutation analyses from the embryos were performed following whole genome amplification of single blastomeres using multiple displacement amplification (MDA). RESULTS: Three embryos were diagnosed as normal and two were transferred on day 4. The cycle resulted in a pregnancy and a live birth of a carrier male infant. Genetic haplotyping analysis of the infant and the leftover MDA samples enabled us to determine which embryo was implanted. The discrepancy in results was explained by allele dropout (ADO) of the mutant allele from the MDA product. CONCLUSIONS: A feasible strategy for PGD of Morquio disease including whole genome amplification by MDA and the use of preimplantation genetic haplotyping is described. MDA product archiving will be useful for future investigations if needed.

Islamic ethical framework for research into and prevention of genetic diseases.

Medical genetics involves the application of genetic knowledge and technology to specific clinical and epidemiologic concerns. Using genetics to benefit society requires that empirically verified knowledge be used within an ethical framework that combines appeal to written precedent with sensitivity to the options of individuals and families dealing with choices and necessities within the laws, norms and traditions of their society. Islamic bioethics is derived from a combination of principles, duties and rights, and to a certain extent a call to virtue, ihsan. It emphasizes prevention, and it teaches that the patient must be treated with respect and compassion and that the physical, mental and spiritual dimensions of the illness experience must be taken into account. Strategic planning for the prevention and care of genetic disorders, and for genomic research, within the context of Islamic religion and culture is promising and may provide lessons to the developed world. Islamic bioethics provides fundamental principles for genetic counseling, particularly in regard to consanguinity, which was part of the Arabian culture long before Islam but which was discouraged by the second Islamic khalifa. These fundamental principles are important for implementing many preventive and genomic research programs and for maintaining flexibility to respond to new biomedical technologies.

Ethical guidelines in genetics and genomics. An Islamic perspective.

We are at a time of unprecedented increase in knowledge of rapidly changing technology. Such biotechnology especially when it involves human subjects raises complex ethical, legal, social and religious issues. A World Health Organization expert consultation concluded that "genetics advances will only be acceptable if their application is carried out ethically, with due regard to autonomy, justice, education and the beliefs and resources of each nation and community." Public health authorities are increasingly concerned by the high rate of births with genetic disorders especially in developing countries where Muslims are a majority. Therefore, it is imperative to scrutinize the available methods of prevention and management of genetic disorders. A minimum level of cultural awareness is a necessary prerequisite for the delivery of care that is culturally sensitive, especially in Islamic countries. Islam presents a complete moral, ethical, and medical framework, it is a religion which encompasses the secular with the spiritual, the mundane with the celestial and hence forms the basis of the ethical, moral and even juridical attitudes and laws towards any problem or situation. Islamic teachings carry a great deal of instructions for health promotion and disease prevention including hereditary and genetic disorders, therefore, we will discuss how these teachings play an important role in the diagnostic, management and preventive measures including: genomic research; population genetic screening pre-marital screening, pre-implantation genetic diagnosis; assisted reproduction technology; stem cell therapy; genetic counseling and others.