BACKGROUND:Tobacco consumption is associated with considerable negative impact on health. Health professionals, including future doctors, should have a leading role in combating smoking in the community.OBJECTIVES:The aims of the study were to assess the prevalence of smoking among medical students of newly established medical colleges in Riyadh city, the capital of Saudi Arabia, as well as to assess students' attitude, practice and their knowledge on the risk factors of tobacco consumption.METHODS:A cross-sectional, questionnaire-based study of students from two medical colleges in Riyadh, Saudi Arabia was carried out. The questionnaire used was anonymous, self-administered and developed mainly from Global Adult Tobacco Survey (GATS).RESULTS:A total of 215 students participated in this study. Forty students (19%) indicated that they smoke tobacco at the time of the study. All of them were males, which raise the prevalence among male students to 24%. Tobacco smoking was practiced by males more than females (P value <0.0001) and by senior more than junior students (<0.0001). About 94% of the study sample indicated that smoking could cause serious illnesses. About 90% of the students indicated that they would advice their patients to quit smoking in the future and 88% thought that smoking should be banned in public areas. Forty-four students (20%) thought that smoking has some beneficial effects, mainly as a coping strategy for stress alleviation.CONCLUSION:Despite good knowledge about the hazards of tobacco consumption, about 25% of the medical students in this study continue to smoke. The main reported reasons should be addressed urgently by policy-makers. Special efforts should be taken to educate medical students on the effective strategies in managing stress during their study as they thought that tobacco smoking could be used as a coping strategy to face such a stress.

Mitochondrial DNA (mtDNA) depletion syndromes (MDS) are severe autosomal recessive disorders associated with decreased mtDNA copy number in clinically affected tissues. The hepatocerebral form (mtDNA depletion in liver and brain) has been associated with mutations in the POLG, PEO1 (Twinkle), DGUOK and MPV17 genes, the latter encoding a mitochondrial inner membrane protein of unknown function. The aims of this study were to clarify further the clinical, biochemical, cellular and molecular genetic features associated with MDS due to MPV17 gene mutations. We identified 12 pathogenic mutations in the MPV17 gene, of which 11 are novel, in 17 patients from 12 families. All patients manifested liver disease. Poor feeding, hypoglycaemia, raised serum lactate, hypotonia and faltering growth were common presenting features. mtDNA depletion in liver was demonstrated in all seven cases where liver tissue was available. Mosaic mtDNA depletion was found in primary fibroblasts by PicoGreen staining. These results confirm that MPV17 mutations are an important cause of hepatocerebral mtDNA depletion syndrome, and provide the first demonstration of mosaic mtDNA depletion in human MPV17 mutant fibroblast cultures. We found that a severe clinical phenotype was associated with profound tissue-specific mtDNA depletion in liver, and, in some cases, mosaic mtDNA depletion in fibroblasts.

Background Diagnosis of primary immunodeficiencies (PIDs) is complex and cumbersome yet important for the clinical management of the disease. Exome sequencing may provide a genetic diagnosis in a significant number of patients in a single genetic test. Methods In May 2013, we implemented exome sequencing in routine diagnostics for patients suffering from PIDs. This study reports the clinical utility and diagnostic yield for a heterogeneous group of 254 consecutively referred PID patients from 249 families. For the majority of patients, the clinical diagnosis was based on clinical criteria including rare and/or unusual severe bacterial, viral, or fungal infections, sometimes accompanied by autoimmune manifestations. Functional immune defects were interpreted in the context of aberrant immune cell populations, aberrant antibody levels, or combinations of these factors. Results For 62 patients (24%), exome sequencing identified pathogenic variants in well-established PID genes. An exome-wide analysis diagnosed 10 additional patients (4%), providing diagnoses for 72 patients (28%) from 68 families altogether. The genetic diagnosis directly indicated novel treatment options for 25 patients that received a diagnosis (34%). Conclusion Exome sequencing as a first-tier test for PIDs granted a diagnosis for 28% of patients. Importantly, molecularly defined diagnoses indicated altered therapeutic options in 34% of cases. In addition, exome sequencing harbors advantages over gene panels as a truly generic test for all genetic diseases, including in silico extension of existing gene lists and re-analysis of existing data. Electronic supplementary material The online version of this article (10.1186/s13073-019-0649-3) contains supplementary material, which is available to authorized users.

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Although the incidence of pediatric IBD in Saudi Arabian children is lower than suggested in the Western literature, there is a significantly increasing trend over time. However, decreased trend in the younger age group over time is identified. Prospective studies will be important to identify the risk factors for IBD in different age groups.