genetic disorder

• A genetic disorder 


  is a disease that is caused by a change, or mutation, in an individual’s DNA.
• Mutation


  is a change in the DNA sequence of an organism due to either errors that occur during DNA replication or environmental factors.
• Diabetes, cancer, Down syndrome, Turner syndrome, hemophilia, cystic fibrosis, and albinism are some of the commonly known genetic disorders
• Some genetic disorders are carried by a dominant allele, whereas others are carried by a recessive allele.
• Single gene disorders are caused by defects in one particular gene due to changes or mutations that occur in the DNA.
• single gene disorders are also known as

  monogenetic disorders
• The pattern of inheritance of disorder

  depends on whether they are controlled by genes on autosomes or by genes on sex chromosomes
• The three major patterns of Mendelian inheritance for genetic disorders and diseases are

  autosomal dominant, autosomal recessive, and X-linked
• Autosomal-dominant disorders ->expressed in the heterozygous condition. ->controlled by genes on one of human autosomes (22 pairs of non sex chromosomes) that do not differ between males and females.->autosomal dominant disorders are inherited in the same way regardless of the sex of the parent or offspring.
• Huntington's disease

  is a well-known example of an autosomal dominant single gene disease. Individuals with a single defective gene will have Huntington’s disease later in life by a progressive neurodegenerative disorder
• Autosomal-recessive disorders -> expressed in homozygous conditions. ->An autosomal recessive disorder will most commonly occur when both parents carry the trait and the offspring receives the defected gene from each parent.

  ->Although both parents are the carriers off the trait, they are unaffected
• ->Cystic fibrosis and Albinism are autosomal recessive disorders controlled by a single autosomal gene with two alleles. A child with cystic fibrosis or albinism has inherited a defective gene from each parent.
• sex-linked inheritances are controlled by genes on the sex chromosomes
• hemophilia, the blood-clotting disorder, is an example of a recessive X-linked disorder that is 


  characterized by the blood’s inability to clot normally.
• Chromosome disorders 


  are disorders resulting from changes in the number or structure of chromosomes.
• chromosomes are the carriers of the genetic material
• chromosomes are the carriers of the genetic material
• abnormalities in the chromosome number or structure can result in disease
• Chromosomal abnormalities typically occur due to errors during cell division.
• Down syndrome or trisomy 21(2n+1), is an example of the most commonly known genetic disorder that occurs when a person has three copies of chromosome 21, which results from an extra chromosome 21 (trisomy 21: three copies of chromosome 21).
• aneuploidy: wrong number of chromosome
• Deletion:


  a part of a chromosome is missing
• Aneuploidy


  wrong number of chromosomes
• Inversion:


  occurs when there are two breaks on a chromosome
• Inversion: occurs when there are two breaks on a chromosome and the segment between the breakpoints flips around and reinserts back into the chromosome;
• Translocation:

  is a rearrangement of a chromosomal segment from one location to another
• Multifactorial disorders


  are complex disorders caused by changes in the combination of multiple genes, complex interaction with environmental and lifestyle factors
• Examples of multifactorial inheritance


  include diabetes and cancer.
• genetic testing


  is important to identify the type of the disorder.
• Genetic counseling 


  is also important because diseases caused by genetic disorders are complicated and may have different psychological and social impacts
• Genetic testing examines the genetic material -> tells an individual about the likelihood and risk of passing genetic disorders on to children. ->It identifies the likelihood of parents who pass a genetic disease or

  or disorder to their childre -> examines if there are any change in our DNA that can inform us the well-being of our health of us and our family.
• Amniocentesis and chorionic villus sampling are examples of diagnostic tests to be taken during pregnancy
• Genetic counseling is the process of checking a family with regard to the medical history and medical records, ordering genetic tests, evaluating the results of these tests and recording, and helping parents understand and reach decisions about what to do next.
• It helps to make informed decisions about genetic testing. ->It gives information about how genetic disorders might affect one’s family in order to increase understanding of genetic disorder that are inherited in the family.'
• Genetic counselors can help people in identifying and interpreting the risks of an inherited disorder, explaining inheritance patterns and suggesting genetic testing
• Gene therapy is


  is the technique that introduces genes into the existing cells to modify a person’s genes to prevent or cure a wide range of diseases
• One of these treatment mechanisms is called gene therapy.
• Somatic gene therapy 


  refers to transferring a section of DNA to somatic cells and the effects will not be passed onto the patient’s children.
• Germ line gene therapy 


  refers to transferring a section of DNA to sex cells and the effects will be passed onto the patient’s children and subsequent generations.
• gene therapy can be done through different mechanisms, such as -> by replacing a disease-causing gene with a healthy copy of the gene -> inactivating a disease-causing gene that is not functioning properly and -> introducing a new or modified gene into the body to help treat the disease