Single gene disorders Autosomal disorders Outline Introduction Types

Single gene disorders Autosomal disorders

Outline ØIntroduction ØTypes of Autosomal single gene disorders ØAutosomal Dominant disorders ØAutosomal recessive ØAutosomal Recessive disorders ØReferences

Outline ØIntroduction Types of Autosomal single gene disorders Autosomal Dominant disorders Autosomal recessive Autosomal Recessive disorders References

Introduction � A genetic disorder is an illness caused by abnormalities in the genome, especially a condition that is present from birth (congenital). � Most genetic disorders are quite rare and affect one person in every several thousands or millions. � Genetic disorders are heritable, and are passed down from the parents' genes. � Other defects may be caused by new mutations or changes to the DNA.

Introduction � In such cases, the defect will only be heritable if it occurs in the germ line. � The same disease, such as some forms of cancer, may be caused by an inherited genetic condition in some people, by new mutations in other people, and by nongenetic causes in still other people.

Introduction � Monogenic disease; Mendelian disorder. � The result of a single mutated gene Over 4000 human diseases are caused by single gene defects. � Single gene disorders can be passed on to subsequent generations in several ways. � Most follow pattern of Mendelian inheritance.

Outline Introduction ØTypes of Autosomal single gene disorders Autosomal Dominant disorders Autosomal recessive Autosomal Recessive disorders References

Types of Autosomal single gene disorders There are two main types of Autosomal single gene disorders: 1. 2. Autosomal dominant Autosomal recessive

Outline Introduction Types of Autosomal single gene disorders ØAutosomal Dominant disorders Autosomal recessive Autosomal Recessive disorders References

Autosomal Dominant � Only one mutated copy of the gene will be necessary for a person to be affected by an autosomal dominant disorder. � Each affected person usually has one affected parent. � The chance a child will inherit the mutated gene is 50%.

Autosomal dominant

Outline Introduction Types of Autosomal single gene disorders Autosomal Dominant ØAutosomal Dominant disorders Autosomal recessive Autosomal Recessive disorders References

Autosomal Dominant disorders There are may autosomal dominant traits and disorders , these disorders include : � Huntington's disease � Hypercholesterolemia � Achondroplasia

Huntington’s Disease � Huntington's disease (HD) is an inherited, degenerative brain disorder which results in an eventual loss of both mental and physical control. � The disease is also known as Huntington's chorea. � Chorea means "dance-like movements" and refers to the uncontrolled motions often associated with the disease.

Hypercholesterolemia �Definition : A genetic disorder of high cholesterol. �Symptoms �High cholesterol �Heart disease �Heart attacks �Fatty skin deposits �Cholesterol deposits in the eyelids �Chest pains or other signs of heart disease

Achondroplasia � Clinical definition: a congenital skeletal dysplasia that results in shortened extremities and macrocephaly and also known as dwarfism. � Etiology: autosomal dominant gain-of-function mutation in fibroblast growth factor receptor. � Symptoms: asymptomatic. � Physical exam : macrocephaly, frontal bossing , shortening of arms and legs.

Achondroplasia

outline Introduction Types of Autosomal single gene disorders Autosomal Dominant disorders ØAutosomal Recessive disorders References

Autosomal Recessive � Autosomal Recessive Two copies of the gene must be mutated for a person to be affected by an autosomal recessive disorder. � An affected person usually has unaffected parents who each carry a single copy of the mutated gene (and are referred to as carriers). � Two unaffected people who each carry one copy of the mutated gene have a 25% chance with each pregnancy of having a child affected by the disorder.

Autosomal Recessive

Outline Introduction Types of Autosomal single gene disorders Autosomal Dominant disorders Autosomal recessive ØAutosomal Recessive disorders References

Autosomal Recessive disorders There are may autosomal recessive traits and disorders , these disorders include : � cystic fibrosis � sickle cell disease � Tay Sachs disease � Spinal muscular atrophy

Cystic Fibrosis � Life threatening, causes thick mucus to build up in various areas of the body (lungs, digestive tract, etc). � protein product produce unusually thick, sticky mucus that: � clogs the lungs � obstructs the pancreas � stops natural enzymes from helping the body break down and absorb food.

Sickle Cell Anemia Disorder � where abnormal hemoglobin (a protein inside red blood cells) is produced and warps red blood cells Sickle cells deliver less oxygen to body’s tissues and can get stuck in small blood vessels � descent Hemoglobin carries oxygen to cells, life expectancy shorter, patients used to die of organ failure between 20 and 40, but now people tend to live into their 50 s in the US anyway.

Tay Sachs disease � Rare disease � Hereditary mutation � Hex-A protein deficiency � Needed to dissolve gangliosides. � Malfunction in brain cells and nervous system.

Spinal Muscular Atrophy �Lesion site = anterior horn cells and motor nuclei of the brainstem �Signs/Symptoms: Hypotonia Weakness Cranial nerve palsies

Outline Introduction Types of Autosomal single gene disorders Autosomal Dominant disorders Autosomal recessive Autosomal Recessive disorders ØReferences

References www. presentationszone. com www. prevention. com http: //step 1. medbullets. com/ https: //en. wikipedia. org http: //drugline. org/ http: //www. rdss. org. sg/ https: //lookfordiagnosis. com https: //www. dreamstime. com https: //healthtipsguru. wordpress. com http: //en. atlaseclamc. org/