How many people get fragile x

However, in the study by Nolin et al. The reason may be that maternal age has less impact on FMR1 allele stability than CGG repeats and AGG interruptions when considering the risk of expansion to full mutation.

Therefore, more evidence is needed to further demonstrate the effect of maternal age on the amplification risk of FMR1 alleles. The accurate calculated risk rate of expansion to full mutation CGG repeats will be an important information for the genetic counseling of families with individuals with FXS and premutation carriers who want to have children.

A calculation model that includes the length of the CGG repeat, the number of AGG interruptions, and maternal age is more precise for genetic counseling. Women who carry CGG repeats in premutation regions with no AGG interruptions have a risk of expansion to full mutation.

Thus, these women should receive prenatal genetic counseling. Although maternal alleles with one or two AGG interruptions have lower risks than those with no AGG interruptions, they still have a risk of amplification to full mutation according to the number of CGG repeats.

If a premutation carrier can be identified in time and the appropriate measures taken, FXS can be reduced or prevented in maternal transmission to some degree. Broad screening of women during early pregnancy or among those who wish to become pregnant is considered a good approach to identify carriers with significant risk of expansion to full mutation during maternal transmission. However, whether to accept the FXS prenatal screening should be a personal decision.

Therefore, improved public awareness of FXS during early prenatal genetic screening can greatly reduce births of FXS children. Obviously, Down syndrome is familiar to Chinese people. However, not everyone recognizes FXS. Although genetic counseling has become very advanced in Western countries, only a few hospitals and institutions can perform genetic testing for FXS in China. The main reason is that the number of CGG repeats cannot be evaluated accurately.

Recently, although, some commercial FXS testing trial kits have been introduced in China, the high price and technical constraints have hindered widespread use of the kits for genetic testing and prenatal diagnosis. Moreover, until now, the cost of genetic testing for FXS has not been covered by medical insurance in China as is screening for congenital hypothyroidism and phenylketonuria 9.

The cost of genetic testing for FXS is a significant family expense, especially in underdeveloped areas. Therefore, many of FXS are underdiagnosed or misdiagnosed in clinic. At present, there is relatively scarce evidence on FXS in China, which is partly due to lack of awareness of FXS among doctors, the public, and the government. A wide range of actively screening for FXS children is rare in China. Unless a highly clinical suspicion, pediatricians will think of this condition.

It may lead to more and more FXS offspring patients in China and will make management and treatment more difficult. In addition, treatments are not always administered in the Chinese FXS population.

Most importantly, FXS treatment is a long-term supportive treatment. Once diagnosed, further medical treatment will be a substantial financial burden for a family.

FXS management also brings great mental stress to the family and society. Therefore, it is critical to consider the basic national condition of China, which is still a developing country with lagging economic strength compared to developed Western countries.

Moreover, China has a very large population. The unique characteristics of China require us to provide appropriate methods for the diagnosis and treatment of FXS. First, we must improve FXS awareness among doctors, the public, and the government. Second, special guidelines should be created by Chinese language experts to guide doctors how best to describe aspects of FXS to patients. Moreover, in the current era of network information, we should make full use of network resources to introduce basic knowledge of FXS to the Chinese public The prevention and treatment of FXS will be the result of comprehensive efforts in various arenas, including government, medical personnel, and the public.

A specialized clinic and research center is an urgent necessity in order to provide the latest knowledge to Chinese medical professionals. More publicity and education are needed to provide information and help to individuals with FXS and their families. MN contributed to conception and design, drafted the manuscript, critically revised the manuscript, and made final approval of the version to be published; YH contributed to conception and design, critically revised manuscript, made final approval of the version to be published, and agreement to be accountable for all aspects of the work; AD contributed to conception and design, critically revised the manuscript, and made final approval of the version to be published; JD contributed to conception and design and made final approval of the version to be published; HJ, QL, and RH contributed to conception and design, critically revised manuscript, and made final approval of the version to be published; JQ contributed to conception and made final approval of the version to be published; JZ contributed to conception, critically revised manuscript, and made final approval of the version to be published.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. National Center for Biotechnology Information , U. Journal List Front Neurol v. Front Neurol. Published online Jun 6. Hagerman 2, 5. Angel Belle C. Randi J. Author information Article notes Copyright and License information Disclaimer. Specialty section: This article was submitted to Neuropediatrics, a section of the journal Frontiers in Neurology.

Received Jan 18; Accepted May The use, distribution or reproduction in other forums is permitted, provided the original author s or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

This article has been cited by other articles in PMC. Abstract Fragile X syndrome FXS is the most common inherited cause of intellectual disability and the leading monogenic cause of autism spectrum disorder. Keywords: fragile X syndrome, prevalence, treatment, prevention, China.

Targeted Treatment for FXS Fragile X mental retardation 1 protein, the translation product of FMR1 , is a translational regulation factor that can control most of the proteins important for synaptic maturation and plasticity.

Genetic Counseling to Prevent FXS Although CGG repeats are stable when they are in the normal range, they show genetic instability in the gray mutation or premutation regions. Author Contributions MN contributed to conception and design, drafted the manuscript, critically revised the manuscript, and made final approval of the version to be published; YH contributed to conception and design, critically revised manuscript, made final approval of the version to be published, and agreement to be accountable for all aspects of the work; AD contributed to conception and design, critically revised the manuscript, and made final approval of the version to be published; JD contributed to conception and design and made final approval of the version to be published; HJ, QL, and RH contributed to conception and design, critically revised manuscript, and made final approval of the version to be published; JQ contributed to conception and made final approval of the version to be published; JZ contributed to conception, critically revised manuscript, and made final approval of the version to be published.

Conflict of Interest Statement The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Footnotes Funding. References 1. Fragile X mental retardation protein and synaptic plasticity. Mol Brain 6 Fragile X spectrum disorders. Intractable Rare Dis Res 3 4 — Mavoglurant in adolescents with fragile X syndrome: analysis of clinical global impression-improvement source data from a double-blind therapeutic study followed by an open-label, long-term extension study.

J Neurodev Disord 8 Fragile X syndrome: psychiatric manifestations, assessment and emerging therapies. Curr Psychiatry Rev 9 1 —8. Hagerman R, Hagerman P. Seizures occur in about 15 percent of males and about 5 percent of females with fragile X syndrome. Most males and about half of females with fragile X syndrome have characteristic physical features that become more apparent with age. These features include a long and narrow face , large ears, a prominent jaw and forehead, unusually flexible fingers, flat feet , and in males, enlarged testicles macroorchidism after puberty.

Mutations in the FMR1 gene cause fragile X syndrome. This protein helps regulate the production of other proteins and plays a role in the development of synapses , which are specialized connections between nerve cells. Synapses are critical for relaying nerve impulses. Normally, this DNA segment is repeated from 5 to about 40 times.

In people with fragile X syndrome, however, the CGG segment is repeated more than times. Loss or a shortage deficiency of this protein disrupts nervous system functions and leads to the signs and symptoms of fragile X syndrome. Most people with this premutation are intellectually normal. In some cases, however, individuals with a premutation have lower than normal amounts of FMRP.

As a result, they may have mild versions of the physical features seen in fragile X syndrome such as prominent ears and may experience emotional problems such as anxiety or depression. Some children with an FMR1 premutation may have learning disabilities or autistic-like behavior.

Fragile X syndrome is inherited in an X-linked dominant pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes.

Although there is no typical presentation, some boys with Fragile X syndrome have a long narrow face, prominent forehead and large testicles. The most significant effects of Fragile X syndrome are:. The level of severity of these effects varies considerably and not every person with Fragile X syndrome will have every one of these characteristics.

This gene produces a protein that helps the brain to function normally. If this gene is changed or altered in any way, it cannot produce its normal protein, which can result in Fragile X syndrome.

Fragile X syndrome is inherited in a way that is known as 'X-linked', as the changed gene is on the X chromosome. This means that men with Fragile X syndrome are often more severely affected than women.

This is because men only have one X chromosome, whereas women have two X chromosomes, only one of which is changed. Although Fragile X syndrome is not that common, affecting around 1 in 3, boys and between 1 in 4, — 6, girls, the number of men and women who are carriers of the Fragile X gene is significantly higher. It is estimated that 1 in women and 1 in men are carriers of the gene. These people are known as 'Fragile X pre-mutation carriers'.

Pre-mutation carriers may not have any symptoms of Fragile X syndrome but they are at risk of passing on the changed FMR1 gene and having a child or grandchild with Fragile X syndrome. People who are Fragile X pre-mutation carriers may also be at risk of developing health problems later in life.

Around 20 per cent of female Fragile X pre-mutation carriers experience reduced fertility or early menopause. These conditions are called Fragile X-associated Disorders. Fragile X syndrome and Fragile X-associated disorders can only be diagnosed by DNA testing — usually by a blood test but sometimes via cheek swab or mouthwash.

If possible, testing should be done at a recognised genetics service. Intellectual disability is the hallmark of this condition and, in females, this may be the only sign of the problem. A specific genetic test polymerase chain reaction [PCR] can now be performed to diagnose fragile X syndrome. This test looks for an expanded mutation called a triplet repeat in the FMR1 gene. There is no specific treatment available for fragile X syndrome.

Supportive therapy for children who have fragile X syndrome includes:. Special education and anticipatory management including avoidance of excessive stimulation to decrease behavioral problems. Medication to manage behavioral issues, although no specific medication has been shown to be beneficial. Vision, hearing, connective tissue problems, and heart problems when present are treated in the usual manner. This condition is inherited in an X-linked dominant pattern.

A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes. The inheritance is dominant if one copy of the altered gene in each cell is sufficient to cause the condition. In most cases, males experience more severe symptoms of the disorder than females.

A striking characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. About Fragile X Syndrome.