MEN2B Case Study

5. Males transmit their Y chromosome to their sons. This means that sons will not inherit an X-linked recessive condition from their father.

Fragile X Syndrome is a genetic condition causing intellectual disability, behavioural and learning challenges and various physical characteristics, it occurs in both genders but effects males more. Also is the most common gene for Autism worldwide, every week in Australia one child is born who is fully affected and 20 children are born who are carriers. It is estimated that 5 per cent of people with a diagnosis of an Autism Spectrum disorder also have Fragile X.

The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

because girls have 2 X chromosomes they are less affected than boy that have 1 Y and 1 X

Fragile X syndrome is inherited in an X- linked dominant pattern. This is because the mutated gene that causes the disorder is located on the X

If the mutated gene attaches itself to one of the sex X chromosomes, then the condition will be considered as X-linked. If one of the altered gene copies is capable of causing the condition in each of the individual’s cells, then the Fragile X syndrome condition is referred to as dominant. However, it has been discovered that sons will never inherit the gene from fathers as the X chromosomes are the only genes responsible for the genetic condition. Sons can only inherit the genes from their mothers (McLennan, 2011). This fact is very unusual considering that males are more severely affected by the conditions than their female counterparts. It can be said that some females act as carriers of this gene which then establishes itself as dominant in males, whereas in females it might be recessive. With the prevalence of this condition, it ranks as the most common inherited genetic and intellectual

Autosomal dominant for classical type. But EDS can also be inherited in autosomal recessive or x-linked fashion-

Fragile X Syndrome is a genetic disorder caused by changes to the FMR1 gene. The FMR1 gene creates a protein that is necessary for normal brain development and it is located on the 23rd chromosome (which makes it X-linked dominant). It affects both females and males, but it is more likely to occur in males and typically presents more severely in males. It is estimated at 1 in 4000 boys are affected, while 1 in 8000 girls are affected. Most males and around half of females present with physical characteristics; long and narrow face, large ears, prominent jaw and forehead, flat feet, and low muscle tone, all of which become more apparent post-puberty. It causes a range of developmental disabilities, from learning disabilities to more serious

Fragile X Syndrome (FXS) also known as , the Martin-Bell, or the marker x syndrome. This genetic disorder is an autosomal dominant. It is a genetic condition that causes a range of developmental problems including learning disabilities and cognitive impairment. Majority of the time males are in more risk than females to getting this genetic disorder. For more proof of this fact statistics say that 1 in 4,000 males and 1 in 8,000 females tend get this disorder.This disorder is caused by the expansion of lengthening of FMR1 gene on the X chromosome. When it lengthens it turns off the production of a protein that is involved in brain development and other functions. This Fragile X gene can be passed down through generation.

As stated before , Fragile X Syndrome is Inherited in a dominant X-linked sequence. The disease is caused by the pattern

The mode of inheritance of sickle cell anaemia is autosomal recessive. This type of inheritance means that the child will not get the disease if both of the parents does not pass down the genes which are defect.

:Albinism is a autosomal recessive disease, which means that a person must have two copies of the defective gene to exhibit symptoms of the disease. The child therefore inherits one defective gene responsible for making melanin from each parents. Because the task of making melanin is complex, there are many different types of albinism, involving a number of different genes.A defect in one of several genes that produce or distribute melanin causes albinism. The defect may result in the absence of melanin production, or a reduced amount of melanin production. The defective gene passes down from both parents to the child and causes albinism.albinism:Until recently, prenatal diagnosis of OCA I was achieved by histologic and electron microscopic

Genetic disorders or heredity diseases are disorders that are caused by a missing gene, abnormal gene, or chromosomal characteristic (The Free Dictionary, 2007). There are to me found many genetic disorders. Klinefelter syndrome is an example of a genetic disorder. Klinefelter syndrome affects the male rather than female (“47, XXY”, 2016).

The gene carrying the defect that produces albinism is recessive, which means that both parents must carry this recessive gene in order to produce a child with the condition. When both parents carry the gene (and neither has albinism), there is a one in four chance with each pregnancy that their child will have albinism. The inheritance pattern of ocular albinism is alittle different. This condition is X-linked, meaning that the recessive gene for ocular albinism is located on the X chromosome. X-linked ocular albinism appears just about only in males who inherit the condition from their mothers.

Dominant and recessive inheritance are useful concepts when it comes to predicting the probability of an individual inheriting certain phenotypes, especially genetic disorders. But the terms can be confusing when it comes to understanding how a gene specifies a trait. This confusion comes about in part because people observed dominant and recessive inheritance patterns before anyone knew anything about DNA and genes, or how genes code for proteins that specify traits.