A combination of ascorbic acid and α-tocopherol to test the effectiveness and safety in the fragile X syndrome: study protocol for a phase II, randomized, placebo-controlled trial.

BACKGROUND: Fragile X syndrome (FXS) is an inherited neurodevelopmental condition characterised by behavioural, learning disabilities, physical and neurological symptoms. In addition, an important degree of comorbidity with autism is also present. Considered a rare disorder affecting both genders, it first becomes apparent during childhood with displays of language delay and behavioural symptoms.Main aim: To show whether the combination of 10 mg/kg/day of ascorbic acid (vitamin C) and 10 mg/kg/day of α-tocopherol (vitamin E) reduces FXS symptoms among male patients ages 6 to 18 years compared to placebo treatment, as measured on the standardized rating scales at baseline, and after 12 and 24 weeks of treatment.Secondary aims: To assess the safety of the treatment. To describe behavioural and cognitive changes revealed by the Developmental Behaviour Checklist Short Form (DBC-P24) and the Wechsler Intelligence Scale for Children-Revised. To describe metabolic changes revealed by blood analysis. To measure treatment impact at home and in an academic environment. METHODS/DESIGN: A phase II randomized, double-blind pilot clinical trial. SCOPE: male children and adolescents diagnosed with FXS, in accordance with a standardized molecular biology test, who met all the inclusion criteria and none of the exclusion criteria. INSTRUMENTATION: clinical data, blood analysis, Wechsler Intelligence Scale for Children-Revised, Conners parent and teacher rating scale scores and the DBC-P24 results will be obtained at the baseline (t0). Follow up examinations will take place at 12 weeks (t1) and 24 weeks (t2) of treatment. DISCUSSION: A limited number of clinical trials have been carried out on children with FXS, but more are necessary as current treatment possibilities are insufficient and often provoke side effects. In the present study, we sought to overcome possible methodological problems by conducting a phase II pilot study in order to calculate the relevant statistical parameters and determine the safety of the proposed treatment. The results will provide evidence to improve hyperactivity control and reduce behavioural and learning problems using ascorbic acid (vitamin C) and α-tocopherol (vitamin E). The study protocol was approved by the Regional Government Committee for Clinical Trials in Andalusia and the Spanish agency for drugs and health products. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01329770 (29 March 2011).

Molecular testing for fragile X: analysis of 5062 tests from 1105 fragile X families--performed in 12 clinical laboratories in Spain.

Fragile X syndrome is the most common inherited form of intellectual disability. Here we report on a study based on a collaborative registry, involving 12 Spanish centres, of molecular diagnostic tests in 1105 fragile X families comprising 5062 individuals, of whom, 1655 carried a full mutation or were mosaic, three cases had deletions, 1840 had a premutation, and 102 had intermediate alleles. Two patients with the full mutation also had Klinefelter syndrome. We have used this registry to assess the risk of expansion from parents to children. From mothers with premutation, the overall rate of allele expansion to full mutation is 52.5%, and we found that this rate is higher for male than female offspring (63.6% versus 45.6%; P < 0.001). Furthermore, in mothers with intermediate alleles (45-54 repeats), there were 10 cases of expansion to a premutation allele, and for the smallest premutation alleles (55-59 repeats), there was a 6.4% risk of expansion to a full mutation, with 56 repeats being the smallest allele that expanded to a full mutation allele in a single meiosis. Hence, in our series the risk for alleles of <59 repeats is somewhat higher than in other published series. These findings are important for genetic counselling.

Distribution of AGG interruption patterns within nine world populations.

The CGG trinucleotide repeat within the FMR1 gene is associated with multiple clinical disorders, including fragile X-associated tremor/ataxia syndrome, fragile X-associated primary ovarian insufficiency, and fragile X syndrome. Differences in the distribution and prevalence of CGG repeat length and of AGG interruption patterns have been reported among different populations and ethnicities. In this study we characterized the AGG interruption patterns within 3,065 normal CGG repeat alleles from nine world populations including Australia, Chile, United Arab Emirates, Guatemala, Indonesia, Italy, Mexico, Spain, and United States. Additionally, we compared these populations with those previously reported, and summarized the similarities and differences. We observed significant differences in AGG interruption patterns. Frequencies of longer alleles, longer uninterrupted CGG repeat segments and alleles with greater than 2 AGG interruptions varied between cohorts. The prevalence of fragile X syndrome and FMR1 associated disorders in various populations is thought to be affected by the total length of the CGG repeat and may also be influenced by the AGG distribution pattern. Thus, the results of this study may be important in considering the risk of fragile X-related conditions in various populations.

Intermediate FMR1 alleles and cognitive and/or behavioural phenotypes.

During the last few years, several studies have reported an excess of intermediate FMR1 alleles in patients with cognitive and/or behavioural phenotypes. Here, we report the frequency of intermediate alleles (IAs) in three pathologies, intellectual disabilities (IDs), attention-deficit/hyperactivity disorder and autism, from different Spanish regions. We found 142 IAs among 9015 patients with ID (1.6%), 4 among the 415 ADHD patients (0.96%) and 4 among the 300 autistic patients (1.3%), similar to the frequency reported in our control population. No evidence was found of an excess of IA at the FRAXA locus in any of the study populations, although geographical variability was detected. Moreover, the analysis of 100 transmissions of IAs showed that 95% of these alleles were stable. Only 3% expanded within the same range and 2% expanded to a full mutation in two generations. No evidence of an association between IAs and behavioural or cognitive phenotypes was found, suggesting that IAs are not clearly implicated in these pathologies.

Expansion of an FMR1 grey-zone allele to a full mutation in two generations.

Fragile X Syndrome is caused by the expansion of an unstable CGG-repeat tract in the 5'-UTR of the FMR1 gene, which generally results in transcriptional silencing and consequent absence of the FMR1 protein. To date, the smallest premutation allele reported to expand to a full mutation allele in a single generation is 59 CGG repeats. Here, we report a single-generation expansion to a full mutation allele (male with approximately 538 CCG repeats) from a mother who is a carrier of a premutation allele of 56 CGG repeats. Furthermore, the maternal grandfather was a carrier of a gray (or intermediate)-zone allele (45 to 54 repeats) of 52 CGG repeats. Thus, in this family, a gray-zone allele expanded to the full mutation range in two generations. Interestingly, the two AGG interruptions present in the grandfather's allele were absent in the mother's premutation allele. These observations underscore the need to consider carriers of alleles of greater than 55 CGG repeats as being at risk for transmission of a full mutation allele in a single generation, and those with even smaller alleles in the gray zone as being at risk of having grandchildren with full mutation alleles.

Screening for expanded alleles of the FMR1 gene in blood spots from newborn males in a Spanish population.

Fragile X syndrome, which is caused by expanded CGG repeats of the FMR1 gene, is associated with a broad spectrum of clinical involvement and is the most common inherited form of intellectual disability. Early diagnosis and intervention are likely to lead to improved outcome for children with fragile X syndrome, but such strategies require better estimates of the frequencies of expanded alleles of the FMR1 gene. In this study, we report the results of a newborn screening study of 5267 male blood spots collected from the Northwest region of Spain as part of the national newborn screening program. The blood spots were screened using a rapid polymerase chain reaction-based method that is capable of identifying the presence of all expanded alleles for both males and females. The screened samples included 199 gray zone alleles, 21 premutation alleles, and two full mutation alleles (1 in 2633). The frequency of premutation alleles was three times higher (1 in 251) than the quoted value of 1 in 813 from a Canadian population and is fully consistent with the results of large-scale Israeli screening studies. Our results demonstrate that newborn screening for the presence of expanded FMR1 alleles is an effective means for defining the distribution of expanded FMR1 alleles in newborn populations; as such, this method is suitable for large-scale newborn screening.

Analysis of the molecular parameters that could predict the risk of manifesting premature ovarian failure in female premutation carriers of fragile X syndrome.

OBJECTIVE: To study three molecular parameters (number of CGG repeats, X-inactivation ratio, and expression of FMR1 mRNA) in premutation carriers of fragile X syndrome with and without premature ovarian failure (POF) to find differences between these two groups that could be useful in reproductive counseling. DESIGN: A retrospective clinical and molecular genetic study of 42 known premutation carriers of fragile X syndrome aged 40 years or older, 25 with POF and 17 without. A blood sample to obtain mRNA was taken from all of them. They all lived in five autonomous communities in northern Spain. RESULTS: Although the relationship among mRNA levels, X-inactivation ratio, and CGG repeats seems to be similar both in women with POF and in those without: in women with POF, the effect of the CGG repeats on the mRNA levels was statistically significant (P = 0.0437), but in women without POF, it was not (P = 0.0724). Moreover, we confirmed previous results on the nonlinear association between CGG repeat number and the manifestation of POF, showing that the likelihood of having POF was significantly higher with fewer than 100 CGG repeats compared with 100 or more CGG repeats (odds ratio = 13.09, P = 0.0240). CONCLUSIONS: Our present work suggests that mRNA and X-inactivation studies in blood are not relevant in predicting POF in female premutation carriers of fragile X syndrome. However, having a permutation of fewer than 100 repeats could represent a significant risk of POF.

ALOX5 promoter genotype and response to montelukast in moderate persistent asthma.

BACKGROUND: It was hypothesized that asthmatic patients with mutant alleles in the leukotriene pathway should not respond to leukotriene receptor antagonists and the concept of a tailored treatment is increasingly supported. METHODS: Sixty-one patients (mean age 24.9 years, range 14-52) with moderate persistent asthma were clinical and immunological assess prior and after a 6-month treatment with montelukast. Tandem repeat polymorphisms were genotyped in the promoter (-147 to -176) of 5-lipoxygenase gene (ALOX5). RESULTS: Thirty-two patients (52.5%) were homozygous for the five repeats allele; 17 (27.9%) were heterozygous (4/5 repeats) and 12 (19.7%) were homozygous for 4/4 repeats. After the montelukast treatment decrease number of asthma exacerbations, improvement of FEV(1) and decreased use of beta(2) agonists was observed in patients with 5/5 or 4/5 repeats. Conversely, the patients with 4/4 repeats genotype did not modify these data after treatment. CONCLUSIONS: It was confirmed that ALOX5 promoter polymorphisms have a clear influence in montelukast response in atopic moderate persistent asthma patients. The genetic study could identify those patients most likely to respond to montelukast.