Objective: Inborn errors of metabolism (IEMs) are disorders with various manifestations that occur mainly in the pediatric population. In countries where consanguineous marriage is common, the association between consanguinity and IEMs is highly important. No studies have been conducted in Iran examining the impact of consanguinity on IEMs. Methods: In this retrospective study, the incidences of metabolic disorders were evaluated for the years 2006 through 2016 in the North East Iran Regional Diagnostic Laboratory (Pardis Clinical and Genetic Laboratory). A total of 13,327 infants with clinical symptoms were referred and investigated for IEMs. Newborn screening was performed on samples from all patients suspected of having IEMs. Results: Of 13,327 infants examined, 60 different IEMs were diagnosed in 1,118. The most frequent disorders among our patients were glucose-6-phosphate dehydrogenase deficiency (G6PDD) (14.04%), methylmalonic and propionic acidurias (MMA/PA) (9.12%), phenylketonuria (PKU) (8%), and isovaleric acidemia (IVA) (6.98%). A significant difference was found in the prevalence of amino acid disorders between the offspring of consanguineous and those of non-consanguineous parents. No statistically significant differences were found between the 2 groups for organic or fatty acids, carnitine or urine cycles, or lysosomal storage disorders. A total of 707 of the 1,118 infants with metabolic diseases (63.24%) were children of consanguineous parents. These findings show that consanguinity can be an important factor in the inheritance of recessive mutations in a homozygous state. Conclusion: This study found a greater frequency of metabolic diseases in offspring of consanguineous parents than in those of non-consanguineous parents in a population with a high rate of consanguinity.
Objectives: The aim of the present study was to develop a robust and easy to use high performance liquid chromatography (HPLC) to analyze 25(OH)D3 in human serum. Background: Vitamin D is a fat-soluble steroid hormone precursor that is mainly produced in the skin by exposure to sunlight. It is also supplied in the diet and plays a pivotal role in calcium homeostasis and skeletal metabolism throughout life. Methods: To assess its analytical performance, we used the RECIPE HPLC Complete Kit and an HPLC-UV instrument. Our HPLC results were compared with a validated electrochemiluminescence method. Results: The method was linear for the lower limit of quantification from 3 ng/l up to at least 200 ng/l for 25(OH) D3, with the following equation for the regression line: y = 0.172 X + 2.45 (R 2 = 0.989). Intra-assay precision was determined by extracting and quantifying 10 serum replicates from one patient. The mean was 37.875 ng/ml, the standard deviation was 0.22, and the coefficient of variation was 0.58%. Comparisons of results demonstrated good agreement between HPLC and ECL methods (R 2 = 0.883). Conclusion: The HPLC assay demonstrates excellent linearity, acceptable accuracy and precision, and good agreement with a validated ECL method. The simple sample preparation and ease of use make it practical for the routine clinical laboratory.
BackgroundAdenosylcobalamin (vitamin B12) is a coenzyme required for the activity of methylmalonyl-CoA mutase. Defects in this enzyme are a cause of methylmalonic acidemia (MMA). Methylmalonic acidemia, cblA type, is an inborn error of vitamin B12 metabolism that occurs due to mutations in the MMAA gene. MMAA encodes the enzyme which is involved in translocation of cobalamin into the mitochondria.MethodsOne family with two MMA-affected children, one unaffected child, and their parents were studied. The two affected children were diagnosed by urine organic acid analysis using gas chromatography-mass spectrometry. MMAA was analyzed by PCR and sequencing of its coding region.ResultsA homozygous deletion in exon 4 of MMAA, c.674delA, was found in both affected children. This deletion causes a nucleotide frame shift resulting in a change from asparagine to methionine at amino acid 225 (p.N225M) and a truncated protein which loses the ArgK conserved domain site. mRNA expression analysis of MMAA confirmed these results.ConclusionWe demonstrate that the deletion in exon 4 of the MMAA gene (c.674 delA) is a pathogenic allele via a nucleotide frame shift resulting in a stop codon and termination of protein synthesis 38 nucleotides (12 amino acids) downstream of the deletion.
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