ABSTRACT
BACKGROUND: Nephrotic syndrome (NS) is one of the most common kidney disorders seen by pediatric nephrologists and is defined by the presence of heavy proteinuria (>3.5 g/24 h), hypoalbuminemia (<3.5 g/dL), edema, and hyperlipidemia. Most children with NS are steroid-responsive and have a good prognosis following treatment with prednisolone. However, 10%-20% of them have steroid-resistant nephrotic syndrome (SRNS) and fail to respond to treatment. A significant proportion of these children progress to kidney failure. METHODS: This retrospective study aimed to determine the underlying genetic causes of SRNS among Omani children below 13 years old, over a 15-year period and included 77 children from 50 different families. We used targeted Sanger sequencing combined with next-generation sequencing approaches to perform molecular diagnostics. RESULTS: We found a high rate of underlying genetic causes of SRNS in 61 (79.2%) children with pathogenic variants in the associated genes. Most of these genetically solved SRNS patients were born to consanguineous parents and variants were in the homozygous state. Pathogenic variants in NPHS2 were the most common cause of SRNS in our study seen in 37 (48.05%) cases. Pathogenic variants in NPHS1 were also seen in 16 cases, especially in infants with congenital nephrotic syndrome (CNS). Other genetic causes identified included pathogenic variants in LAMB2, PLCE1, MYO1E, and NUP93. CONCLUSION: NPHS2 and NPHS1 genetic variants were the most common inherited causes of SRNS in Omani children. However, patients with variants in several other SRNS causative genes were also identified. We recommend screening for all genes responsible for SRNS in all children who present with this phenotype, which will assist in clinical management decisions and genetic counseling for the affected families.
Subject(s)
Nephrotic Syndrome , Infant , Child , Humans , Adolescent , Nephrotic Syndrome/drug therapy , Nephrotic Syndrome/genetics , Nephrotic Syndrome/diagnosis , Retrospective Studies , Genetic Predisposition to Disease , Membrane Proteins/genetics , DNA Mutational AnalysisABSTRACT
Objectives: To describe the demographic distribution of cystic fibrosis (CF) in Omani children, estimate the national prevalence, and provide updated mutational panels of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Methods: We conducted a retrospective cross-sectional study of all CF patients who had been diagnosed and followed-up at Sultan Qaboos University Hospital and Royal Hospital in Oman between 2006 and 2020. Data were collected from electronic hospital records and telephone interviews. Results: A total of 227 patients with CF were included in the study. Geographical clusters of the disease were identified in the governorates of Al-Batinah, A'Dhahirah, and A'Dakhiliyah. Parental consanguinity and family history of CF were present in 68.3% and 69.6% of the patients, respectively. The most common CFTR mutation was p.Ser549Arg (52.0%), followed by p.Phe508del (12.3%), and c.2988+1G>A (4.4%). Three novel CFTR mutations were identified, viz., Leu88TyrFs*, p.Asp192Val, and c.4242+1G>C. Conclusions: The estimated prevalence of CF in Oman is 10.3 per 100 000 individuals. Premarital genetic counseling and preimplantation genetic testing are recommended in CF-prevalent regions.
