GENETIC DISEASES

 Pathogenic disease

TYPES OF DISEASES

 Deficiency disease

Hereditary diseases

 Physiological disease

Polygenic disorders

Monogenic disorders

Chromosomal aberrations

WHAT IS A DISEASE?

A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with 

specific symptoms and signs.

WHAT IS A GENETIC DISEASE?

• It is a disorder caused by genetic factors and especially abnormalities in the human genetic material (genome). There are four main types of genetic disorders. Of course, some of these changes in genome can cause interesting advantages in specific environments (Darwinian Fitness). But there is no doubt that all these abnormalities (disorders) bring destructive results to a living being in the present environment.

• There are three types (human) of genetic diseases are:

CLASSIFICATION

TYPES OF GENETIC DISEASES:• 1. Disorders with multifactorial inheritance (polygenic)

• 2. Monogenic (mendelian) disorders• 3. Chromosomal aberrations

1) MULTIFACTORIAL / POLYGONIC GENETIC DISEASES:

• The second type of human genetic diseases is caused by mutations in more than one genes.

•  The environment combines with these mutations in order these diseases to appear.

•  We can easily conclude that polygenic disorders are more complicated than the previous type (single gene diseases). These abnormalities are also difficult to analyze, because there are many factors that researchers should take into consideration in order to reach to some useful conclusions.

•  Many well known chronic diseases are Multifactorial Genetic Diseases. Everybody knows Alzheimer, diabetes, obesity and arthritis. Besides many cancer types are caused by multi mutations.

OBESITY• Obesity is a medical condition in which excess body fat has accumulated to the 

extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems. Body mass index (BMI), a measurement which compares weight and height, defines people as overweight (pre-obese) if their BMI is between 25 and 30 kg/m2, and obese when it is greater than 30 kg/m2.

• Obesity increases the likelihood of various diseases, particularly heart disease, type 2 diabetes, obstructive sleep apnea, certain types of cancer, and osteoarthritis .

• Obesity is most commonly caused by a combination of excessive food energy intake, lack of physical activity, and genetic susceptibility, although a few cases are caused primarily by genes, endocrine disorders, medications or psychiatric illness. Evidence to support the view that some obese people eat little yet gain weight due to a slow metabolism is limited; on average obese people have a greater energy expenditure than their thin counterparts due to the energy required to maintain an increased body mass

CANCER  CELL BRAINDIABETES

OBESITYARTHRITIS

2) SINGLE-GENE/MONOGENIC GENETIC DISEASES:

     In this category the starting point is a mutation/change in one gene. 

• How a change in the sequence of a single gene can cause severe disorders? 

• Genes code for proteins which are some of the most important tools for the living beings, and also take place in the structures of the cells. The results of a mutation that happens in a part of gene that codes for a functional part of a protein are unwelcome. The protein is no more functional and as a result, many severe consequences take place. 

• Almost 6000 single gene disorders are known and it is estimated that 1 of 200 newborns face a single gene genetic disorder. Some of these are sickle cell anemia, cystic fibrosis, Aicardi Syndrome, Huntington’s disease.

SICKLE  CELL  DISEASE

Sickle-cell disease (SCD), recessive genetic blood disorder with over dominance, characterized by red blood cells that assume an 

abnormal, rigid, sickle shape. Sickling decreases the cells' flexibility and results in a risk of various complications. The 

sickling occurs because of a mutation in the hemoglobin gene.Sickle-cell disease may lead to various acute and chronic 

complications, several of which have a high mortality rate. Sickle cell disease is prevalent in many parts of India, where the prevalence has ranged from 9.4 to 22.2% in endemic areas. 

Blood transfusions are often used in the management of sickle cell disease in acute cases and to prevent complications by 

decreasing the  number of red blood cells (RBC) that can sickle by adding normal red blood cells.

CYSTIC FIBROSISSICKLE CELL ANEMIA

AICARDI SYNDROME

HUNTINGTON DISEASE

3) CHROMOSOMAL GENETIC DISEASES:

• Chromosomes are big DNA molecules composed from genes. The chromosomes are located in the cell nucleus.

•  Abnormalities in the structure, number (and not only) of the chromosomes can cause some of the most dangerous genetic disorders.

•  This type of disorders seem to be much easier to observe because they are, sometimes, detected by examination with microscope.

•  Down Syndrome is the most well known disease caused by chromosomal abnormalities. In this disorder there is a third copy of chromosome 21 (there are two copies of each chromosome in the cells of healthy humans). Chromosomal diseases can be also caused by segments and joins of parts of chromosomes.

DOWN SYNDROME• Down syndrome, or Down's syndrome is

a chromosomal condition caused by the presence of all or part of an extra Down syndrome is a chromosomal condition characterized by the presence of an extra copy of genetic material on the 21st chromosome, either in whole (trisomy 21) or part (such as due to translocations). The effects and extent of the extra copy vary greatly among people, depending on genetic history, and pure chance.

• Individuals with Down syndrome may have some or all of the following physical characteristics: microgenia (an abnormally small chin), an unusually round face, macroglossia (protruding or oversized tongue), an almond shape to the eyes caused by an epicanthic fold of the eyelid, upslanting palpebral fissures(the separation between the upper and lower eyelids), shorter limbs, a single transverse palmar crease (a single instead of a double crease across one or both palms), poor muscle tone, and a larger than normal space between the big and second toes. Health concerns for individuals with Down syndrome include a higher risk for congenital heart defects, gastroesophageal reflux disease, recurrent ear infections that may lead to hearing loss, obstructive sleep apnea, thyroid dysfunctions, and obesity.

•  21st chromosome

DOWN SYNDROME

DNA

CHROMOSOME

 chromosomal translocations and rearrangements

WILSON’S DISEASEWilson's disease is an recessive genetic disorder in which copper accumulates in tissues; this manifests as neurological or psychiatric symptoms and liver disease. It is treated with medication that 

reduces copper absorption or removes the excess copper from the body, but occasionally a liver transplant is required. Liver disease 

may present as tiredness, increased bleeding tendency or confusion. 

In general, a diet low in copper-containing foods is recommended, with the avoidance of mushrooms, nuts and chocolates. Various treatments are available for Wilson's disease. Some increase the removal of copper from the body, while others prevent the 

absorption of copper from the diet.

AUTOSOMAL RECESSIVE

• majority of mendelian disorders• only homozygotes are affected, heterozygotes (parents) are only carriers

• 25% of descendants are affected• if the mutant gene occurs with low frequency - high probability in consanguineous marriages

• onset of symptoms often in childhood• frequently enzymatic defect• testing of parents and amnial cells.

PREVENTION

• Many diseases and disorders can be prevented through a variety of means. These include sanitation, proper nutrition, adequate exercise, vaccinations.A prevention or preventive therapy is a way to avoid an injury, sickness, or disease in the first place. A treatment or cure is applied after a medical problem has already started. A treatment attempts to improve or remove a problem, but treatments may not produce permanent cures, especially in chronic diseases. 

TREATMENT

• Medical therapies or treatments are efforts to cure or improve a disease or other health problem. In the medical field, therapy is synonymous with the word "treatment". Among psychologists, the term may refer specifically to psychotherapy or "talk therapy". Common treatments include medications, surgery, medical devices, and self-care. Treatments may be provided by an organized health care system, or informally, by the patient or family members.

• Treatment for medical emergencies must be provided promptly, often through an emergency department or, in less critical situations, through an urgent care facility.

•  self-care and public health measures.

 

MADE BY:ESHLEEN WALIA (12)SIMRAN UPPAL(29)MANVI GUPTA(14)

SHRADDHA  S. MOHANTY(28)AKSHITA GARG(4)

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