Prevalence of DNA-Repair Gene mutations in Mexican men with prostate cancer.

INTRODUCTION AND OBJECTIVE: Mexico reported 26,742 new cases of prostate cancer in 2020. Different risk factors have been identified in the pathogenesis of prostate cancer. Among them, genetic factors and alterations or mutations in specific genes have been described in different ethnic groups worldwide. The aim of our study is to report the prevalence of germline DNA-repair gene mutations in Mexican patients with prostate cancer. MATERIAL AND METHOD: We performed germline genetic testing in 50 patients with localized prostate cancer and 50 patients with metastatic prostate cancer. Demographic, clinical, and histopathological data were collected. RESULTS: Thirty-seven germline mutations were identified in 32 patients. The most commonly affected genes were ATM in 6%, followed by FANCA (5%), and ATR (4%). BRCA2 mutations were identified in 3%. The frequency of mutations was higher in the metastatic group. DISCUSSION AND CONCLUSION: The results of our study show different mutations from those reported in different populations or regions. The use of PARP inhibitors is indicated in patients with germline mutations, specifically BRCA2, showing improvement in overall survival and progression free survival. To our knowledge, this is the first study reporting the prevalence of mutations in DNA-repair genes in Mexican patients with prostate cancer.

Non-functional alternative splicing caused by a Latino pathogenic variant in a case of PMM2-CDG.

We report on a Mexican mestizo with a multisystemic syndrome including neurological involvement and a type I serum transferrin isoelectric focusing (Tf IEF) pattern. Diagnosis of PMM2-CDG was obtained by clinical exome sequencing (CES) that revealed compound heterozygous variants in PMM2, the encoding gene for the phosphomannomutase 2 (PMM2). This enzyme catalyzes the conversion of mannose-6-P to mannose-1-P required for the synthesis of GDP-Man and Dol-P-Man, donor substrates for glycosylation reactions. The identified variants were c.422G>A (R141H) and c.178G>T, the former being the most frequent PMM2 pathogenic mutation and the latter a previously uncharacterized variant restricted to the Latino population with conflicting interpretations of pathogenicity and that we here report causes leaky non-functional alternative splicing (p.V60Cfs*3).

Identification through exome sequencing of the first PMM2-CDG individual of Mexican mestizo origin.

Congenital Disorders of Glycosylation (CDG) are scarcely reported from Latin America. We here report on a Mexican mestizo with a multi-systemic syndrome including neurological involvement and a type I transferrin (Tf) isoelectric focusing (IEF) pattern. Clinical exome sequencing (CES) showed known compound missense variants in PMM2 c.422G > A (p.R141H) and c.395 T > C (p.I132T), coding for the phosphomanomutase 2 (PMM2). PMM2 catalyzes the conversion of mannose-6-P to mannose-1-P required for the synthesis of GDP-Man and Dol-P-Man, donor substrates for glycosylation reactions. This is the third reported Mexican CDG patient and the first with PMM2-CDG. PMM2 has been recently identified as one of the top 10 genes carrying pathogenic variants in a Mexican population cohort.

[Rearrangement of the alpha RAR and pml genes in promyelocytic leukemia]. / Reordenamiento de los genes RAR alpha y pml en la leucemia promielocítica.

The purpose of this work was to assess the re-arrangement of RAR-alpha and pml genes in a group of patients with acute promyelocytic leukaemia (APL) in different stages of the disease. Twenty-two patients with APL were studied. Of them, 17 were at the onset and 5 had achieved already complete haematological remission (CR). Evolutive post-remission studies were performed in 8 cases. The cytogenetic analysis was carried out at diagnosis by means of the G-band technique in 14 patients. The molecular study of RAR-alpha and pml genes was made with the Southern method. The common anomaly, t(15;17) was present in 7 of the 9 cases with evaluable metaphases (78%), in one case a 17q+ was the only cytogenetic alteration and another patient had normal karyotype. The molecular study showed re-arrangement of one or both genes involved in the translocation in the 17 patients studied at the onset of the APL. Those patients studied only in CR showed a germinal configuration. Rearrangement bands reappeared in 3 of the 8 patients evaluated along their clinical course. These results are in concordance with previous studies, in which re-arrangement of RAR-alpha and pml genes had been found in APL, despite there are instances in which no cytogenetic anomalies are found; this confirms the interest of molecular studies in the diagnosis and follow-up of APL patients.