Fragile X Syndrome (FXS) is a genetic disease due to a CGG trinucleotide expansion, named full mutation (greater than 200 CGG repeats), in the fragile X mental retardation 1 gene locus Xq27.3; which leads to an hypermethylated region in the gene promoter therefore silencing it and lowering the expression levels of the fragile X mental retardation 1, a protein involved in synaptic plasticity and maturation. Individuals with FXS present with intellectual disability, autism, hyperactivity, long face, large or prominent ears and macroorchidism at puberty and thereafter. Most of the young children with FXS will present with language delay, sensory hyper arousal and anxiety. Girls are less affected than boys, only 25% have intellectual disability. Given the genomic features of the syndrome, there are patients with a number of triplet repeats between 55 and 200, known as premutation carriers. Most carriers have a normal IQ but some have developmental problems. The diagnosis of FXS has evolved from karyotype with special culture medium, to molecular techniques that are more sensitive and specific including PCR and Southern Blot. During the last decade, the advances in the knowledge of FXS, has led to the development of investigations on pharmaceutical management or targeted treatments for FXS. Minocycline and sertraline have shown efficacy in children.
Sirenomelia and cyclopia share etiologic and pathogenic characteristics. A cluster of these two patterns of malformation in the city of Cali, Colombia, is described. Four sirenomelia and four cyclopia cases were born within a 165 days period in one hospital in Cali. The lapse between conception dates of first and last cases was shorter for sirenomelia (53 days) than for cyclopia (231 days). Based on ECLAMC (Latin American Collaborative Study of Congenital Malformations) published data, the observed/expected ratio (5.7) for both defects is statistically significant (P < 0.001). Mother's residence during the first trimester of pregnancy is concentrated in a same city quarter for four of the eight cases, close to a know polluting active landfill, and the other four cases, along the Cauca river, downstream from this landfill. Birth prevalence rates for two sentinel anomalies, that is, anal and esophageal atresia for sirenomelia and oral clefts for DeMyer holoprosencephaly spectra, were not higher in Cali than in the rest of ECLAMC material. The Computer Assisted Telephone Interviewing was applied to mothers of the 8 patients, and 32 matched controls. Seven of 295 variables were associated with sirenomelia, 3 of them related to house tap water, one to exposure to street drugs, one to physical injury, and 2 secondary to abnormal pregnancy outcome. None was associated with cyclopia. Results from hair dosage of heavy metals in the 8 patient's mothers were inconsistent. The time-space cluster is nonrandom for sirenomelia, and possibly random for cyclopia. The polluting landfill remains as a possible etiological factor.
Fragile X syndrome (FXS) is caused by a full mutation on the FMR1 gene and a subsequent lack of FMRP, the protein product of FMR1. FMRP plays a key role in regulating the translation of many proteins involved in maintaining neuronal synaptic connections; its deficiency may result in a range of intellectual disabilities, social deficits, psychiatric problems, and dysmorphic physical features. A range of clinical involvement is also associated with the FMR1 premutation, including fragile X-associated tremor ataxia syndrome, fragile X-associated primary ovarian insufficiency, psychiatric problems, hypertension, migraines, and autoimmune problems. Over the past few years, there have been a number of advances in our knowledge of FXS and fragile X-associated disorders, and each of these advances offers significant clinical implications. Among these developments are a better understanding of the clinical impact of the phenomenon known as mosaicism, the revelation that various types of mutations can cause FXS, and improvements in treatment for FXS.
This study shows that in Ricaurte the carrier frequencies of FMR1 expanded alleles (premutations and FMs) are higher than those reported in the literature, suggesting that Ricaurte constitutes a genetic cluster of FXS.
Fragile X syndrome (FXS) is the most common cause of inherited intellectual disabilities and autism spectrum disorders, and it is an X‐linked disorder in which there is a deficiency of the fragile X mental retardation 1 protein. This protein is crucial in regulating translation of mRNAs related to dendritic maturation and cognitive development. The phenotype of FXS is characterized by neurobehavioral alterations, social deficits, communication difficulties, and findings which suggest an alteration of connective tissue, especially in the ligaments and muscles, cardiovascular system and genitourinary system. Connective tissue connects and supports all other tissues of the body and is composed of cells and extracellular matrix (ECM). Several proteins have been involved in the connective tissue abnormalities associated with the FXS, such as matrix metalloproteinase 9, which plays an important role in the homeostasis of the ECM, being a potential therapeutic target for certain tetracycline antibiotics that have shown beneficial effects in FXS. Here, we review connective tissue problems described in FXS.
BackgroundMaternal serum concentrations of folate, homocysteine, and vitamin B12 have been associated with pre-eclampsia. Nevertheless, reported studies involve limited number of cases to reliably assess the nature of these associations. Our aim was to examine the relation of these three biomarkers with pre-eclampsia risk in a large Colombian population.Materials and methodsDesign: A case-control study.Setting: Cases of pre-eclampsia and healthy pregnant controls were recruited at the time of delivery from eight different Colombian cities between 2000 and 2012.Population or Sample: 2978 cases and 4096 controls were studied. Maternal serum concentrations of folate, homocysteine, and vitamin B12 were determined in 1148 (43.6%) cases and 1300 (31.7%) controls. Also, self-reported folic acid supplementation was recorded for 2563 (84%) cases and 3155 (84%) controls.Analysis: Adjusted odds ratios (OR) for pre-eclampsia were estimated for one standard deviation (1SD) increase in log-transformed biomarkers. Furthermore, we conducted analyses to compare women that reported taking folic acid supplementation for different periods during pregnancy.Main Outcomes Measures: Odds ratio for pre-eclampsia.ResultsAfter adjusting for potential confounders in logistic regression models, the OR for pre-eclampsia was 0.80 (95% CI: 0.72, 0.90) for 1SD increase in log-folate, 1.16 (95%CI: 1.05, 1.27) for 1SD increase in log-homocysteine, and 1.10 (95%CI: 0.99, 1.22) for 1SD increase in log-vitamin B12. No interactions among the biomarkers were identified. Women who self-reported consumption of folic acid (1 mg/day) throughout their pregnancy had an adjusted OR for pre-eclampsia of 0.86 (95%CI: 0.67, 1.09) compared to women that reported no consumption of folic acid at any point during pregnancy.ConclusionsMaternal serum concentrations of folate were associated as a protective factor for pre-eclampsia while concentrations of homocysteine were associated as a risk factor. No association between maternal vitamin B12 concentrations and preeclampsia was found.
Fragile X Syndrome (FXS) is a neurodevelopmental disorder caused by a CGG expansion in the FMR1 gene located at Xq27.3. Patients with the premutation in FMR1 present specific clinical problems associated with the number of CGG repeats (55–200 CGG repeats). Premutation carriers have elevated FMR1 mRNA expression levels, which have been associated with neurotoxicity potentially causing neurodevelopmental problems or neurological problems associated with aging. However, cognitive impairments or neurological problems may also be related to increased vulnerability of premutation carriers to neurotoxicants, including phenobarbital. Here we present a study of three sisters with the premutation who were exposed differentially to phenobarbital therapy throughout their lives, allowing us to compare the neurological effects of this drug in these patients.
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