Fragile X Syndrome – Definition and Explanations – Techno-Science.net

introduction

THE fragile X syndrome is a syndrome that is first cause from hereditary intellectual disability (second cause of mental retardation of genetic origin (genetics (from the Greek genno γεννώ = to give birth) is…) after trisomy (trisomy is a special case of aneuploidy, a chromosomal abnormality….) 21)

• |Around 6% of children with learning disabilities tested in institutions (learning is the acquisition of know-how, so the process…) are carriers of this syndrome. This pathology (pathology, an ancient Greek term literally means speech that…) does not lead to a malformation (A malformation is a congenital morphological change in a tissue or organ…) and children affected by this pathology normal have growth.
• This pathology, especially in boys, is mainly manifested by mental retardation and various behavioral disorders that can have an autistic character. Girls affected by this condition are affected differently, generally with moderate mental retardation.
• This pathology affects 12,000 people in France.

related diseases

• FRAX syndrome
• FRAX syndrome
• FRAXF syndrome
• Fragile X syndrome type 1
• Fragile X syndrome type 2′
• Fragile X syndrome type 3
• Intentional tremor (tremors are abnormal involuntary, rhythmic and oscillating movements, weak…) / fragile X-cerebellar ataxia

etiology

• Mutation of the FMR 1 (Fragility Mental Retardation 1) gene at the q27.3 locus of the X chromosome (The X chromosome is one of the two sex chromosomes found in humans and certain animals…).
• The mutation consists of an abnormal repeat of the sequence CGG (cytosine guanine guanine). In normal individuals, the CGG sequence is repeated less than 40 times.
• In people with fragile X syndrome, this sequence is repeated more than 200 times, we’re talking up to thousands of times complete mutationThis causes the gene responsible for the disease to malfunction.

epidemiology

• 2. Cause of mental retardation of genetic origin
• 1. Cause of intellectual disability of genetic origin in boys
• This disease affects one in 4,000 boys and one in 7,000 girls.
• Recent studies show that the prevalence of premutation in women is 1/260.

diagnosis

prenatal

Typical physical symptoms of fragile X syndrome: elongated face, prominent forehead, prognathic chin, large ears

• There are no ultrasound signs indicating the presence of a fetus with fragile X syndrome.
• In high-risk families, prenatal diagnosis is possible using the technique PCR (Polymerase chain reaction) or other methods such Southern blot performed by trophoblasticectomy or amniocentesis (amniocentesis is a medical procedure for diagnosis…).
• Certain techniques do not allow diagnosis of the premutation.
• Please note that the standard karyotype performed to diagnose trisomy 21 does not allow for the diagnosis of fragile X syndrome.

Preimplantation diagnosis is possible. It is the same concept as IVF with research (scientific research is primarily any action taken to…) in molecular biology (molecular biology (sometimes abbreviated as Biomol or BM) is a discipline …) of embryonic cells. Preimplantation diagnosis of Fragile X is done by searching for genetic markers.

The hospital (A hospital is a place destined to take care of people suffering from …) Antoine Béclère in collaboration with the Necker Hospital are the only ones on time (The hour is a unit of measurement of time The word also denotes the current magnitude…) in the practice of preimplantation diagnosis in the Paris region. It is necessary to wait on average a year and a half between submitting an application dossier and receiving a grant (the payload in English: the payload) (The average is a statistical measure that characterizes the elements of a series of…). what is effective…) effective.

postnatal

The search for fragile X syndrome should be carried out in all children with intellectual disabilities. The diagnosis is usually not made until the age of three.