Fragile X syndrome is actually the most common inherited form of mental retardation currently known to mankind. Fragile X Syndrome is inherited in an X-linked dominate pattern. Referring to X-linked because, if the mutated gene that causes the disorder is located on the X chromosome. (Fragile X syndrome- Genetic Home Reference, 2012). Males will only pass the FXS gene to their daughters (females) and not to their sons (males). (Fragile X Syndrome Diseases and Conditions, 2012). While on the other hand, females will actually have a 50/50 chance to pass the FXS gene along to both their sons (males) and daughters (females). Fragile X Syndrome is known to occur in approximately 1 in 4000 males and in 1 and 8000 females. (Coffee B, et al, 2009). …show more content…
(Usdin & Kumari, 2015). The FMR1 also referred to as the “fragile x mental retardation” gene provides instructions for making a specific protein called FEMP. The same gene also causes fragile X syndrome when in the full mutation range (200 or greater CGG repeats). FEMP also referred to as the “Fragile X Mental Retardation Protein” which is a protein that helps regulates the production of other proteins. This protein, most commonly found in the brain, is essential for normal cognitive development and female reproductive function. (Berry-Kravis et al., 2007). Mutations of this gene can lead to fragile X syndrome, mental retardation, premature ovarian failure, autism, Parkinson's disease, developmental delays and other cognitive deficits. Normally the CGG amino acid Triplet repeats on average thirty to forty times within the DNA segment whereas, someone with Fragile X Syndrome would have the CGG Triplet repeats between 55 to 200 times sometimes even more. The abnormally expanded CGG segment turns off (silences) the FMR1 gene which prevents the gene from producing the production of the protein FEMP. (Liu, Y. By silencing or becoming methylated the gene there becomes inadequate amounts of FMR1. The mechanism of the abnormal Triplet is what fails at cellular level and disrupts …show more content…
Fragile X Syndrome causes a range of developmental problems including, learning disabilities and cognitive impairment. These problems include physical features from, large ears, long face, soft skin and large testicles (called “macroorchidism”) in post-pubertal males. Not every with the FM1 gene has symptoms of Fragile X Syndrome, because the body may still be able to make FMRP. A few things that affect how much FMRP that can makes includes, the size of the mutation, the number of cells that have can make include the size of mutation, the number of cells that have mutations and lastly whether or not someone is female. These factors determine how much FMRP protein is made and whether or not signs and symptoms of Fragile X Syndrome will be mild or
Autism Spectrum Disorder (ASD) has two main core criteria, according to the Diagnostic and Statistical Manual of Mental Disorders fifth edition (DSM-5). The first of the two criteria is ‘Persistent Deficits in Social Communication and Interaction across Multiple Contexts’ under which there are three categories. The first being deficits in social emotional reciprocity which may include atypical social approach and failure of the back and forth exchange of normal conversation. In addition, there may be a failure to respond or initiate social interaction as well as reduced emotions, interest or effect sharing. In the scenario ‘Ben loves Trains’ it is indicated that Ben is content to play alone for hours, he doesn’t interact with his sister in
ACH, is an interesting disease, one that after many years of research still remains a partial mystery. The fact that a single nucleotide on one chromosome can so greatly affect an individual is astounding, especially coupled with the fact that this mutation is so homogenious in genotype and phenotype. With more skeletal dysplasias being connected to FGFR3, research has increased to fully determine and define the pathways involved with this gene. Determining the reason for such a high mutation frequency and the link to paternal age are also being looked into. Once there is more understanding of how this mutation affects the body, treatments and possibly cures can be found for these individuals.
Genetic disorders can be caused by many of the 46 chromosomes in human cells. This specific disorder is linked to a mutation in the long arm of the X, or 23rd chromosome. The mutation is recessive, meaning a normal X chromosome can hide it. Females have two X chromosomes allowing them to hide the mutated recessive one, making them a carrier of the gene, while males only have one X chromosome, meaning that they are unable to hide the mutation and they become effected by the disease. Therefore if a male carries the gene, he is affected because he has no way of dominating the recessive gene, but if a female carries it, she is only a carrier and has a 50/50 chance of passing it on to her baby. This may seem like a high probability however, only one in every fifty thousand male births will have this immunodeficiency disease.
Marfan syndrome is a Single Gene Mutation and the gene that is mutated is FBN 1 (Fibrillin 1).The gene is located on chromosome 15 and the disorder’s mode of inheritance is autosomal dominant. This means that females and males are equally affected and that only one gene, “abnormal” gene is needed from either parent to be inherited in. Fibrillin 1 basically affects the elasticity of connective tissue. The gene makes many fibrillin proteins and these fibrillin proteins then join together to form a long, and string like object called microfibrils.
Spinal Muscular Atrophy affects about 8 out of every 100,000 live births and also causes death among more babies than any other genetic disease out there. About one in every forty people has this gene in them but may not have SMA so they are a genetic carrier. But in order for a child to have SMA, both parents have to carry the mutated gene and passed it to the child. Therefore this causes the child to have double copies of the abnormal gene. About 1 in 40 men and 1 in 80 women are carriers of the gene.
The fetus in utero may show signs of slow growth and organs may not develop correctly. After birth there can be physical defects evidenced by a smooth skin surface between upper lip and nose, the nose may be upturned, wide set eyes and an extremely thin upper lip. The head may be small in circumference and brain size, deformities of the joints, vision and hearing problems, heart defects and problems with bones and kidneys. There may be problems with the central nervous system and brain, including poor memory and judgement, learning disorders, delayed development, poor coordination and/or balance and hyperactivity or jitteriness, and mood swings. Children born with FAS may have difficulty is school, have poor social skills, have trouble adapting to change, lack impulse control, unable to stay on task and find it hard to plan or work towards a goal. The severity and negative effects range from subtle to serious, they are always
Myotonic dystrophy, type 1, is a genetic disorder which is linked to chromosome number 19 in humans. The dystrophia myotonica protein kinase gene is located on the q arm of the chromosome at the locus of 13.32. It is an autosomal dominant disorder, which means that the individuals that are affected by this disorder and contain at least one dominant allele for the dystrophia myotonica protein kinase gene. The disorder is caused by a series of repeats of a trinucleotide region that is expanded beyond the normal levels (Musova et al., 2009). The trinucleotide region is a series of repeats of CTG in the untranslated region of the dystrophia myotonica protein kinase gene. The severity of the disorder is associated with the number of repeats the individual has within the gene. Normal individuals tend to have between 5 and 37 repeats while an individual with a very mild myotonic dystrophy may have 50 to 150 repeats, and if the disorder is discovered at the time of birth the individual will have over 2,000 repeats of the trinucleotide region (Musova et al., 2009). Myotonic dystrophy, type 1, affects multiple organ systems of the body and is relatively slow to progress. Myotonic dystrophy, type 1, is categorized by alterations of the beating pattern of the heart, faulty dystrophin proteins, clouding of the lens of the eye, decreased functionality of the gonads, balding, and myotonia (Musova et al., 2009). Myotonia is described as the slow relaxation of any muscle type, which will cause the individual to use extended effort to simply relax the muscles after they have been contracted. Muscular dystrophy causes an individual to experience muscular deg...
Rett syndrome is a neurological disorder that mainly affects females. According to “The Molecular Pathology of Rett syndrome: Synopsis and Update”, it states that the disorder starts to be recognizable when the child is between six to eighteen months of age. The affected child will loose their ability to speak and hand movements. Through research, MECP2 is in the X chromosome gene (2006). An estimate of females that suffer from Rett syndrome is 1 in 1,000 and in the United States, it is approximately 16,000 young and adult females that are affected (Rett Syndrome, 2008). In my paper, I will give a brief history of how Rett syndrome was first noticed, discuss the dysfunction in the brain, the development and behavior, and possible treatments.
One of the most characteristic features of Autism Spectrum Disorders (ASD) is its prominent higher prevalence among the male gender in comparison with the female gender. Although rates of ASD are consistent across cultures, these rates vary significantly by gender. It is the male gender that seems to be more affected by ASD with an average male-to-female ratio of 4.2:1, affecting 1 in 70 males and only 1 in 315 females (Fombonne, 2009). Although a well-known fact, the causes for such a great difference among sex ratios still remains unexplained, there are several hypotheses and studies trying to explain the reason for this inequality. In this paper I will outline some of the different attempts to explain the differences between the sex ratios. Among these attempts we can find diverse hypotheses that vary from the role of the sex hormones and genetic vulnerability to the biases of medical professionals during the diagnostic process (Goldman, 2013).
Studies have shown that Autism is more prevalent in boy than in girls, with a male to female ratio of 3:1 (Muhle et al., 2004). It is unclear why exactly autism tends to develop in males rather than females, but the fact that males are more statistically prone to develop Autism, suggests that the genes associated with the sex X chromosome may ...
Wattendorf, Daniel. "Diagnosis and Management of Fragile X Syndrome." Am Fam Physician (2005): 111-113. Web. 30 May 2010. .
Sex-linked disorders only affect males and are passed down through female carriers. A boy inherits the disorder when he receives an X chromosome with a mutated dystrophin gene (the genetic cause) from his mother. The dystrophin gene is the largest gene found in nature and was identified through a positional cloning approach. It's a highly complex gene, a large rod-like cytoskeletal protein which is found at the inner surface of muscle fibers. (www.ncbi.nlm.nih.gov)
He published a comprehensive medical description of the syndrome. It was not until 1959, that it became clear the syndrome was due to lack of sex chromosome material. Turner's Syndrome is a rare chromosomal disorder that affects one in approximately 2,500 females. Females normally have two X-chromosomes. However, in those with Turner's Syndrome, one X chromosome is absent or is damaged.