Phenylketonuria (PKU) is an inborn error of amino acid metabolism caused by mutations in the phenylalanine hydroxylase (PAH) gene, characterized by intellectual deficit and neuropsychiatric complications in untreated patients with estimated frequency of about one in 10,000 to 15,000 live births. PAH deficiency can be detected by neonatal screening in nearly all cases with hyperphenylalaninemia on a heel prick blood spot. Molecular testing of the PAH gene can then be performed in affected family members. Herein, we report molecular study of 635 patients genetically diagnosed with PKU from all ethnicities in Iran. The disease-causing mutations were found in 611 (96.22%) of cases. To the best of our knowledge, this is the most comprehensive molecular genetics study of PKU in Iran, identifying 100 distinct mutations in the PAH gene, including 15 previously unreported mutations. Interestingly, we found unique cases of PKU with uniparental disomy, germline mosaicism, and coinheritance with another Mendelian single-gene disorder that provides new insights for improving the genetic counseling, prenatal diagnosis (PND), and/or pre-implantation genetic diagnosis (PGD) for the inborn error of metabolism group of disorders.

Isolated Methylmalonic acidemia/aciduria (MMA) is a group of inborn errors of metabolism disease which is caused by defect in methylmalonyl-CoA mutase (MCM) enzyme. The enzyme has a key function in the catabolism of branched chain amino acids (BCAA, isoleucine, and valine), methionine, and threonine. MCM is encoded by a single gene named "MUT". Other subtypes of MMA are caused by mutations in cblA (encoded by MMAA) and cblB (encoded by MMAB), which is involved in the synthesis of methylmalonyl-coenzyme A cofactor. Different types of mutations have been identified as the cause of MMA. However, the mutation spectrum of MMA in Iran has not been studied so far. Here, we aimed to investigate the MMA causative mutations in the Iranian population. Using STR (Short Tandem Repeat) markers, we performed autozygosity mapping to identify the potential pathogenic variants in 11 patients with clinical diagnosis of MMA. Nineteen STR markers which are linked to the MUT, MMAA and MMAB genes (the genes with known causative mutations in MMA) were selected for PCR-amplification using two recently designed multiplex PCR panels. Next, the families that were diagnosed with homozygous haplotypes for the candidate genes were directly sequenced. Five novel mutations (c.805delG, c.693delC, c.223A > T, c.668A > G and c.976A > G in MUT) were identified beside other 4 recurrent mutations (c.361insT in MUT, c.571C > T and c.197-1 G > T in MMAB and c.1075C > T in MMAA). In silico analyses were also performed to predict the pathogenicity of the identified variants. The mutation c.571C > T in MMAB was the most common mutation in our study.

BackgroundDysferlinopathies are a group of autosomal recessive limb‐girdle muscular dystrophies (LGMDs) caused by mutations in DYSF (#603,009). This gene encodes a transmembrane protein called dysferlin. Since there are few reports on Iranian dysferlinopathy patients, we tried to identify the DYSF mutations in affected individuals of Iran.MethodsEight unrelated Iranian families have been selected for this study. Sanger sequencing followed by haplotype analysis was performed to identify individual variations in DYSF sequence. Identified variants were analyzed, and their pathogenicity was interpreted according to the recommendations of the American College of Medical Genetics and Genomics.ResultsWe identified two new mutations in DYSF, the first one is a nonsense mutation c.2419C > T (p.Gln807*), which eliminates downstream part of the protein. Another novel mutation is c. (1,053 + 1_1,054‐1)_(1,397 + 1_1,398‐1)del, which causes deletion of the DNA segment from exon 12 to exon 15.ConclusionTwo of the other six families are from the same ethnicity and share the same mutation and haplotype patterns, suggesting a founder mutation. Genetic analysis of dysferlinopathy can prevent a wrong diagnosis of myositis for these patients.

Background Glanzmann thrombasthenia (GT) is a rare autosomal recessive abnormality of platelet aggregation with quantitative and/or qualitative abnormality of αIIbβ3 integrin. The αIIbβ3 is a platelet fibrinogen receptor, which is required for platelet aggregation, firm adhesion, and also spreading. The disease is more prevalent in the populations with a higher rate of consanguineous marriages as in some Middle Eastern populations including Iraq, Jordan, and Iran. Different types of mutations in ITGA2B and ITGB3 genes have been previously reported to cause the disease. Result In this study, 16 patients with the clinical diagnosis of GT were studied. Direct sequencing of the exons and exon-intron boundaries of the above genes revealed mutations in 14 patients (detection rate: 87.5%). Briefly, out of fifteen types of identified mutations, 14 were novel. Seven mutations in the ITGB3 gene included 4 missense [c.2T > C, c.155 G > T, c. 538 G > A, c.1990 G > T], one nonsense mutation [c.1303 G > T], a small deletion [c.1656_1658delCTC] and a deletion of one nucleotide [c.401delA]. Mutations in the ITGA2B were 8 different mutations consisting 2 missense [c.286 T > A, c.842 C > T], 2 deletions [c.1899 del T, c.189-319_236del], an insertion [c.1071_1072insG] and one splice site mutations [c.409–3 C > G], one synonymous mutation that might alter the normal splicing process [c.1392 A > G] and a nonsense mutation [c.1555 C > T]. The causative mutation in 2 patients remained unknown. Using long-range PCR and sequencing, we found a rather large deletion. The break point of this deletion covers 319 nt from the last part of the first intron and 48 nt from the beginning of the second exon of ITGA2B gene. The deletion was also detected in two unrelated patients with the same ethnicity. In addition, in silico analyses of novel mutations were performed. Conclusion There was no recurrent mutation in the studied population. This may be due to either small sample size or the heterogeneity of the studied population.

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