We report the results of clinical exome sequencing (CES) on >2,200 previously unpublished Saudi families as a first-tier test. The predominance of autosomal-recessive causes allowed us to make several key observations. We highlight 155 genes that we propose to be recessive, disease-related candidates. We report additional mutational events in 64 previously reported candidates (40 recessive), and these events support their candidacy. We report recessive forms of genes that were previously associated only with dominant disorders and that have phenotypes ranging from consistent with to conspicuously distinct from the known dominant phenotypes. We also report homozygous loss-of-function events that can inform the genetics of complex diseases. We were also able to deduce the likely causal variant in most couples who presented after the loss of one or more children, but we lack samples from those children. Although a similar pattern of mostly recessive causes was observed in the prenatal setting, the higher proportion of loss-of-function events in these cases was notable. The allelic series presented by the wealth of recessive variants greatly expanded the phenotypic expression of the respective genes. We also make important observations about dominant disorders; these observations include the pattern of de novo variants, the identification of 74 candidate dominant, disease-related genes, and the potential confirmation of 21 previously reported candidates. Finally, we describe the influence of a predominantly autosomal-recessive landscape on the clinical utility of rapid sequencing (Flash Exome). Our cohort's genotypic and phenotypic data represent a unique resource that can contribute to improved variant interpretation through data sharing.

No abstract

Standardization of the diagnostic routine for children with congenital heart disease associated with pulmonary arterial hypertension (PAH-CHD) is crucial, in particular since inappropriate assignment to repair of the cardiac lesions (e.g., surgical repair in patients with elevated pulmonary vascular resistance) may be detrimental and associated with poor outcomes. Thus, members of the Congenital Heart Disease and Pediatric Task Forces of the Pulmonary Vascular Research Institute decided to conduct a survey aimed at collecting expert opinion from different institutions in several countries, covering many aspects of the management of PAH-CHD, from clinical recognition to noninvasive and invasive diagnostic procedures and immediate postoperative support. In privileged communities, the vast majority of children with congenital cardiac shunts are now treated early in life, on the basis of noninvasive diagnostic evaluation, and have an uneventful postoperative course, with no residual PAH. However, a small percentage of patients (older at presentation, with extracardiac syndromes or absence of clinical features of increased pulmonary blood flow, thus suggesting elevated pulmonary vascular resistance) remain at a higher risk of complications and unfavorable outcomes. These patients need a more sophisticated diagnostic approach, including invasive procedures. The authors emphasize that decision making regarding operability is based not only on cardiac catheterization data but also on the complete diagnostic picture, which includes the clinical history, physical examination, and all aspects of noninvasive evaluation.

No abstract

Novel Arab-specific mutations were identified in the CFTR gene underlying cystic fibrosis. As a result of this study, the CFTR mutation detection rate among Arabs with cystic fibrosis is now comparable to that of other populations.

Non-CF bronchiectasis is a common problem in Saudi Arabia. Early recognition and institution of treatment with proper vaccination of available anti-bacterial and anti-viral vaccines are encouraged to prevent progression of the disease.

Cardiac catheterization is important in the diagnosis and risk stratification of pulmonary hypertensive vascular disease (PHVD) in children. Acute vasoreactivity testing provides key information about management, prognosis, therapeutic strategies, and efficacy. Data obtained at cardiac catheterization continue to play an important role in determining the surgical options for children with congenital heart disease and clinical evidence of increased pulmonary vascular resistance. The Pediatric and Congenital Heart Disease Task Forces of the Pulmonary Vascular Research Institute met to develop a consensus statement regarding indications for, conduct of, acute vasoreactivity testing with, and pitfalls and risks of cardiac catheterization in children with PHVD. This document contains the essentials of those discussions to provide a rationale for the hemodynamic assessment by cardiac catheterization of children with PHVD.

A descriptive study was undertaken to characterize the cystic fibrosis transmembrane regulator gene mutations (CFTR) in the Saudi Arabian cystic fibrosis (CF) population in relation to clinical presentation and demographic and ethnic origin. During the period October 1992 to September 1997, 70 patients from 46 families were diagnosed as having CF, based on a typical clinical picture and sweat chloride levels > 60 mmol/l and were screened for CFTR mutations. Twelve mutations were identified in 34 families, which constitutes 70% of the CF alleles in the study group. Pancreatic insufficiency (PI) was found in the following mutations: 1548delG in exon 10 (15%) which occurred mainly in native Saudi patients in the central province; 3120 + 1G-->A in intron 16 (10%) and H139L in exon 4 (7%), found mainly in native Saudis from the eastern province; delta F508 mutation (13%) which occurred mainly in expatriates of Middle Eastern origin from different provinces; L117X in exon 19 (2%); G115X in exon 4 (2%); 711 + 1G-->A in intron 5 (2%); N 1303K in exon 21 (2%) and 425del42 in exon 4 (1%); I1234V in exon 19 (13%) with a predominance of nasal polyps and a variable degree of PI and lung disease; R553X in exon 11 (1%), with electrolyte imbalance; and S549R in 11 (2%) with pancreatic sufficiency and minimal pulmonary disease. The clinical picture did not differ significantly between patients of different ethnic origins with the same CFTR mutation.