ABSTRACT
FMR1 premutation carriers (55-200 CGGs) are at risk of developing Fragile X-associated primary ovarian insufficiency as well as Fragile X-associated tremor/ataxia syndrome. FMR1 premutation alleles are also associated with a variety of disorders, including psychiatric, developmental, and neurological problems. However, there is a major concern regarding clinical implications of smaller CGG expansions known as intermediate alleles (IA) or gray zone alleles (45-54 CGG). Although several studies have hypothesized that IA may be involved in the etiology of FMR1 premutation associated phenotypes, this association still remains unclear. The aim of this study was to provide new data on the clinical implications of IA. We reviewed a total of 17 011 individuals: 1142 with primary ovarian insufficiency, 478 with movement disorders, 14 006 with neurodevelopmental disorders and 1385 controls. Similar IA frequencies were detected in all the cases and controls (cases 1.20% vs controls 1.39%, P = .427). When comparing the allelic frequencies of IA ≥ 50CGGs, a greater, albeit not statistically significant, number of alleles were detected in all the cohorts of patients. Therefore, IA below 50 CGGs should not be considered as risk factors for FMR1 premutation-associated phenotypes, at least in our population. However, the clinical implication of IA ≥ 50CGGs remains to be further elucidated.
Subject(s)
Alleles , Fragile X Mental Retardation Protein/genetics , Genetic Predisposition to Disease , Genetic Variation , White People/genetics , Adult , Female , Gene Frequency , Genetic Association Studies , Genotype , Humans , Male , Middle Aged , Population Surveillance , Spain , Young AdultABSTRACT
Genome complexity and diversity can be due to Alternative Splicing (AS), a process by which one gene can generate multiple mRNA isoforms and then several proteins. This is part of a normal process of variation on an individual, and when it is disrupted or modified, may trigger disease. To date, there are many pathologies described due to the effects of altered splicing isoforms, and effort is focused on the description of new ones. The design of drug target has to consider splicing, as in many occasions, a drug might have effect on different isoforms, instead of on the particular one implicated in the pathology. Interestingly, the strategies used to alter splicing can be used to modify a form towards the canonical one, or towards an aberrant one, when the latter one has a beneficial effect on the individual. Here we describe differential splicing, diseases produced by alterations on the mRNA isoforms, and drugs or methods used to restore these alterations.
