{'fraction_non_alphanumeric': 0.038033395176252316, 'fraction_numerical': 0.027829313543599257, 'mean_word_length': 5.058988764044944, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
A faster strategy for prenatal diagnosis of fragile X syndrome

Fragile X syndrome (FXS; OMIM # 309 550), an Xlinked dominant disorder with reduced penetrance, is the most common form of inherited mental retardation, with a frequency of 1 in 4000 males and 1 in 8000 females (Hagerman and Hagerman, 2002). In affected boys, the phenotype of FXS includes delay in language acquisition and/or behavioural troubles. This disorder is caused by mutations in the FMR1 gene, most commonly involving an expansion of an unstable trinucleotide cytosine-guanine-guanine (CGG) repeat in its 5′ untranslated region. The CGG repeat is polymorphic in the unaffected population, with alleles from 6 to about 55 CGGs. Premutations (PM) are moderate expansions (from 55 to about 200 CGGs) that are unmethylated and are found in asymptomatic FXS carrier males and females. However, these alleles may be associated with two clinical disorders: a fragile Xassociated primary ovarian insufficiency (FXPOI) and a fragile X-associated tremor/ataxia disorder (FXTAS) (Sherman, 2000; Jacquemont et al., 2003). Full mutations (FM), which cause FXS patients to develop mental retardation (males or 50% females), have over 200 copies of repeats and are associated with hypermethylation of this region. Hypermethylation is clearly the main and critical process responsible for the FXS phenotype, abolishing the FMR1 expression in the human brain (Fu et al., 1991). Nevertheless, some rare cases of unmethylated CGG great expansions have been described in normal FXS patients (Tassone et al., 2000). One of the most common methods of FXS molecular diagnosis is Southern blot analysis (Rousseau et al., 1991) which allows measuring the amount of CGG expansions as well as the determination of the methylation status. This test requires large amounts of DNA and is labour-intensive and time-consuming. Furthermore, it doesn’t allow determination of methylation process in most DNAs extracted from chorionic villi samples (CVS) because of its low sensitivity and the timing of methylation is not (or not totally) present at the eighth to tenth week of pregnancy (Willemsen et al., 2002). As