Gene therapy approaches for GM1 gangliosidosis: Focus on animal and cellular studies.

One of the most important inherited metabolic disorders is GM1 gangliosidosis, which is a progressive neurological disorder. The main cause of this disease is a genetic defect in the enzyme ß-galactosidase due to a mutation in the glb1 gene. Lack of this enzyme in cells (especially neurons) leads to the accumulation of ganglioside substrate in nerve tissues, followed by three clinical forms of GM1 disease (neonatal, juvenile, and adult variants). Genetically, many mutations occur in the exons of the glb1 gene, such as exons 2, 6, 15, and 16, so the most common ones reported in scientific studies include missense/nonsense mutations. Therefore, many studies have examined the genotype-phenotype relationships of this disease and subsequently using gene therapy techniques have been able to reduce the complications of the disease and alleviate the signs and symptoms of the disease. In this regard, the present article reviews the general features of GM1 gangliosidosis and its mutations, as well as gene therapy studies and animal and human models of the disease.

The Impact of Methylenetetrahydrofolate Reductase (MTHFR) Sperm Methylation and Variants on Semen Parameters and the Chance of Recurrent Pregnancy Loss in the Couple.

BACKGROUND: Recurrent pregnancy loss (RPL) defined as three or more consecutive spontaneous miscarriages before the 20th week of gestation is caused by different factors including genetic and epigenetic background. However the involvement of paternal background on RPL is an interesting novel argument, which is not well studied. The main focus of the present study was to investigate for the association of paternal methylenetetrahydrofolate reductase (MTHFR) epigenotypes with sperm parameters and RPL. Moreover, the frequency of two of MTHFR Single Nucleotide Polymorphisms (SNPs) in males was assessed. METHODS: This is a case-control study. Methylation Specific PCR (MSP) was used to evaluate the methylation status of MTHFR promoter on sperm DNA of 25 male partners of RPL and 25 male partners of non-RPL couples. PCR-RFLP method was used to analyze 1,298 A>C (rs1801131) and 677 C>T (rs1801133) polymorphisms. RESULTS: No significant difference was observed in frequency of methylated MTHFR epigenotype between RPL and non-RPL males. Furthermore, methylated MTHFR epigenotype was more frequent (but not statistically significant) among men with abnormal sperm parameters compared to normal-sperm men. Among studied polymorphisms, only the mutated allele of C677T showed statistically higher prevalence among RPL males. CONCLUSIONS: Although our results do not establish any connection between MTHFR epigenotypes and RPL they do highlight the impact of C677T in the pathology.

Mutation Analysis in Classical Phenylketonuria Patients Followed by Detecting Haplotypes Linked to Some PAH Mutations.

BACKGROUND: Deficiency of phenylalanine hydroxylase (PAH) enzyme and elevation of phenylalanine in body fluids cause phenylketonuria (PKU). The gold standard for confirming PKU and PAH deficiency is detecting causal mutations by direct sequencing of the coding exons and splicing involved sequences of the PAH gene. Furthermore, haplotype analysis could be considered as an auxiliary approach for detecting PKU causative mutations before direct sequencing of the PAH gene by making comparisons between prior detected mutation linked-haplotypes and new PKU case haplotypes with undetermined mutations. METHODS: In this study, 13 unrelated classical PKU patients took part in the study detecting causative mutations. Mutations were identified by polymerase chain reaction (PCR) and direct sequencing in all patients. After that, haplotype analysis was performed by studying VNTR and PAHSTR markers (linked genetic markers of the PAH gene) through application of PCR and capillary electrophoresis (CE). RESULTS: Mutation analysis was performed successfully and the detected mutations were as follows: c.782G>A, c.754C>T, c.842C>G, c.113-115delTCT, c.688G>A, and c.696A>G. Additionally, PAHSTR/VNTR haplotypes were detected to discover haplotypes linked to each mutation. CONCLUSIONS: Mutation detection is the best approach for confirming PAH enzyme deficiency in PKU patients. Due to the relatively large size of the PAH gene and high cost of the direct sequencing in developing countries, haplotype analysis could be used before DNA sequencing and mutation detection for a faster and cheaper way via identifying probable mutated exons.