Genetics

diseases

colon cancerDefinition: colon cancer forms when uncontrolled

cell growth starts with cells in the large intestine.It is inherited within family members.

Symptoms: diarrhea, Weakness or fatigue, Unexplained weight loss , Rectal bleeding or blood in the stool and Pain, cramps, or gas in the abdomen.

Diagnosis: physical exam and conducts a colonoscopy or a barium enema x-ray (lower G series).

Treatment: surgery, chemotherapy, and radiation therapy.The prevention: eat healthy and doing exercising.

HypothyroidismDefinition: Hypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone.

Causes: The thyroid makes hormones that control the way every cell in the body uses energy. This process is called metabolism.

Hypothyroidism is more common in women and people over age 50.

Symptoms: Weakness, Heavier and irregular menstrual periods, Decreased taste and smell, Thickening of the skin and Slow speech.

Diagnosis: a physical exam, Blood tests.Treatment: - replacing the thyroid hormone that you are lacking, -

Levothyroxine medicine.

Turner syndromeDefinition :chromosomal condition that affects

development in females.Symptoms: The most common feature of Turner

syndrome is short stature, which becomes evident by about age 5.

Most cases of Turner syndrome are not inherited.How common it: This condition occurs in about 1 in

2,500 newborn girls worldwide.Genetic changes: Turner syndrome is related to the

X chromosome, which is one of the two sex chromosomes.

Diagnosis: diagnosed by amniocentesis or chorionic villous sampling

Treatment: Growth hormone therapy, Sex hormone replacement therapy, Consultations, and Diet.

Down syndromeDefinition: Down syndrome is a chromosome

associated with intellectual disability, Symptoms: facial appearance, and weak muscle tone

(hypotonia) in infancy.Most cases of Down syndrome are not inherited.How common it: Down syndrome occurs in about 1 in

830 newborns. Genetic changes: Most cases of Down syndrome result

from trisomy 21, which means each cell in the body has three copies of chromosome 21 instead of the usual two copies.

Diagnosis: Initially the diagnosis is based on physical characteristics that are commonly seen in babies with Down syndrome.

pachyonychia congenitaDefinition: Pachyonychia congenita is a condition that

primarily affects the nails and skin. Symptoms: Thick nails , blisters and calluses on the palms

of the hands, a white growth on the tongue, and a variety of cysts.

Most cases of Turner syndrome are not inherited.

How common it: There are probably several thousand people worldwide with this disorder.

Genetic changes: it is occur when a mutation occur on keratin gene which located on chromosome 12 and another on chromosome 17.

Diagnosis: PC is often misdiagnosedTreatment: There is no cure for PC, and drug therapies are

limited.

Smith-Magenis syndromeDefinition: Smith-Magenis syndrome is a developmental

disorder that affects many parts of the body. Symptoms: mild to moderate intellectual disability,

delayed speech and language skills, distinctive facial features, sleep disturbances, and behavioral problems.

Smith-Magenis syndrome is typically not inherited.How common it: Smith-Magenis syndrome affects at least

1 in 25,000 individuals worldwide. genetic changes: Given that SLOS is an autosomal

recessive disorder, mutations in DHCR7 on both copies of chromosome 11 are necessary to have the disorder.

Diagnosis: SLOS is diagnosed upon finding an elevated 7DHC:total sterol ratio in fetal tissues, or increased levels of 7DHC in amniotic fluid.

Treatment: surgery.

Sickle cell diseaseDefinition: Sickle cell disease is a group of disorders that

affects hemoglobin. People with this disorder have atypical hemoglobin molecules called hemoglobin S, which can distort red blood cells into a sickle, or crescent, shape.

This condition is inherited in an autosomal recessive pattern.How common is it: Sickle cell disease affects millions of

people worldwide. symptoms: symptoms of sickle cell disease usually begin in early

childhood, low number of red blood cells (anemia), repeated infections, and periodic episodes of pain.

Causes: When red blood cells sickle, they break down prematurely, which can lead to anemia.

Diagnosis: by blood test (HbSS).Treatment: Children born with sickle-cell disease will undergo

close observation by the pediatrician and will require management

by a hematologist to assure they remain healthy.

Severe combined immunodeficiencyDefinition:SCID is a group of inherited disorders that cause

severe abnormalities of the immune system. These disorders lead to reduced or malfunctioning T- and B-lymphocytes, the specialized white blood cells made in the bone marrow and the thymus gland to fight infection.

How common is it :It is affect at least 1 in 100,000 births.Symptoms: Infants with SCID often suffer from recurrent,

severe respiratory infections. Genetic changes: Most cases of SCID are due to An autosomal

recessive mutations in the gene encoding the common gamma chain ( c), γa protein that is shared by the receptors for interleukins IL-2, IL-4, IL-7, IL-9, IL-15 and IL-21.

• The most common type is caused by a problem in a gene found on the X chromosome and affects only males. Females may be carriers of the condition

Diagnosis: genetic counseling and early blood testingTreatment: bone marrow transplantation.

PhenylketonuriaDefinition: it is an autosomal recessive disorder that increases the

levels of a substance called phenylalanine in the blood. Phenylalanine is a building block of proteins (an amino acid) that is obtained through the diet. It is found in all proteins and in some artificial sweeteners.

How common it : In the United States, PKU occurs in 1 in 10,000 to

15,000 newborns. Symptoms: Babies born with PKU usually have no symptoms at first. But

if the disease is left untreated, babies experience severe brain damage.Genetic changes: PKU is caused by a mutation in a gene on

chromosome 12. The gene codes for a protein called PAH an enzyme in the liver.

diagnosis: A small blood sample is taken from the baby's heel or arm and checked in a laboratory for high levels of phenylalanine.

Treatment: People who have PKU must eat a protein-free diet, because nearly all proteins contain phenylalanine. Infants are given a special formula without phenylalanine. Older children and adults have to avoid protein-rich foods such as meat, eggs, cheese, and nuts. They must also avoid artificial sweeteners with a spertame, which contains phenylalanine.

Neurofibromatosis type 1Definition: Neurofibromatosis type 1 is a condition

characterized by changes in skin coloring (pigmentation) and the growth of tumors along nerves in the skin, brain, and other parts of the body.

Symptoms: scoliosis (curvature of the spine), learning disabilities, vision disorders, and epilepsy.

Causes: NF-1 is caused by a mutation of a gene on the long arm of chromosome 17 which encodes a protein known as neurofibromin which plays a role in cell signaling.

Inheritance: NF-1 is inherited in an autosomal dominant fashion, although it can also arise due to spontaneous mutation.

Diagnosis: Prenatal testing, Post-natal testing, and Radiologic features.

Treatment: There is no cure or treatment for NF1, but surgery can remove tumors and correct malformed bones

maple syrup urine diseaseDefinition: MSUD is a potentially deadly disorder that affects

the way the body breaks down three amino acids, leucine, isoleucine, and valine.

Inheritance: MSUD is inherited in an autosomal recessive pattern..

Genetic changes: The most common defect is caused by a mutation in a gene on chromosome 19 that encodes the alpha subunit of the

BCKD complex (BCKDHA).Symptoms: A baby who has the disorder may appear

normal at birth. But within three to four days, the symptoms appear. These may include: loss of appetite, fussiness, and sweet-smelling urine.

Diagnosis: In some states, all babies are screened for MSUD within 24 hours after birth. A blood sample taken from the baby's heel is analyzed for high leucine levels.

Treatment: Treatment involved dietary restriction of the amino acids leucine, isoleucine, and valine.

How common it: MSUD is an extremely rare disorder; only 1 in 180,000 babies is born with MSUD.

Huntington's disease Definition: Huntington's disease is an inherited disease that

causes the progressive breakdown (degeneration) of nerve cells in the brain.

Inheritance: Huntington's disease is inherited in an autosomal dominant fashion.

Causes: he disease is caused by an autosomal dominant mutation in either of an individual's two copies of a gene called Huntingtin

Symptoms: chorea, or slowed saccadic eye movements, abnormal posturing

How common it: More than 15,000 Americans have HD. At least 150,000 others have a 50 percent risk of developing the disease

Diagnosis: Medical diagnosis, and Genetic counselingTreatment: There is no cure for HD, but there are treatments

available to reduce the severity of some of its symptoms. For many of these treatments, comprehensive clinical trials to confirm their effectiveness in treating symptoms of HD specifically are incomplete

Adenosine deaminase (ADA) Definition: Adenosine deaminase (ADA) deficiency is an inherited

disorder that damages the immune system and causes severe combined immunodeficiency (SCID).

Inheritance: ADA deficiency is an autosomal recessive disorder.Symptoms: pneumonia, chronic diarrhea, and widespread skin

rashes.Causes: Some mutations in the gene for adenosine deaminase

cause it not to be expressed.Diagnosis: Doctors can identify ADA deficiency during the

mother's pregnancy (1) by taking a tiny sample of tissue from the amniotic sac where the baby develops, or (2) by looking at enzyme levels in a fetal blood sample taken from the umbilical cord. After the child is born, doctors can test a sample of his or her blood to see if it contains ADA.

Treatment: There are no real cures for ADA deficiency. but doctors have tried to restore ADA levels and improve immune system function with a variety of treatments: Bone marrow transplantation , Transfusions of red blood cells , and Gene therapy .

alpha-1 antitrypsin deficiencyDefinition: Alpha-1 antitrypsin deficiency is an inherited disorder

that may cause lung disease and liver disease. Symptoms: shortness of breath, wheezing, weight loss, and

recurring respiratory infections. How common it: This disorder affects about 1 in 1,500 to 3,500

individuals with European ancestry. It is uncommon in people of Asian descent

Genetic changes: Serpin peptidase inhibitor, clade A, member 1 (SERPINA1) is a gene that translates the protein Alpha 1-antitrypsin. SERPINA 1 has been localized to chromosome 14q32.

Diagnosis: Computed tomography of the lung showing emphysema and bullae in the lower lung lobes of a subject with type ZZ alpha-1-antitrypsin deficiency.

Treatment: lung-affected A1AD patients may receive intravenous infusions of alpha-1 antitrypsin, derived from donated human plasma

Called (augmentation therapy ), liver transplantation for liver-affected patients.

Williams syndromeDefinition: Williams syndrome is a rare genetic disorder that

affects a child's growth, physical appearance, and cognitive development.

Genetic changes: People who have Williams syndrome are missing genetic material from chromosome 7, including the gene elastin.

Symptoms: mental retardation, heart defects, unusual facial features , low birth weight, low muscle tone, and kidney abnormalities.

Inheritance: Williams syndrome is considered an autosomal dominant condition, most cases are not inherited.

How common is it: One out of every 10,000 babies is born with Williams syndrome.

Diagnosis: The diagnosis of it doing by using a special technique called FISH (fluorescent in situ hybridization).

Treatment: There is no cure for Williams syndrome. Patients must be continually monitored and treated for symptoms throughout their lives.

albinismCauses: Albinism is caused by a defect in one of several genes

that produce or distribute melanin (natural pigment). The defect may result in the absence of melanin production, or a reduced amount of melanin production. Albinism is inherited and requires the defective gene to be passed down by both parents.

How common it: one in every 17,000 people in the United States has some type of albinism.

Symptoms: an absence of color in the hair, skin, or eyes, lighter than normal coloring of the hair, skin, or eyes, and patches of skin that have an absence of color

Diagnosis: genetic testes and the main test for albinism is simply an eye examination.

Treatment: There is no cure for albinism. Treatments and aids can help the symptoms and reduce the risk of damage to the skin and eyes.

Cystic FibrosisDefinition : Cystic fibrosis is a genetic disorder that

affects the respiratory and digestive systems.Symptoms: coughing or wheezing, respiratory illnesses

(such as pneumonia or bronchitis), weight loss, salty-tasting skin, and greasy stools.

Genetic changes: it is caused by changes in a pair of genes. Everyone has two copies of the cystic fibrosis gene, but a person has cystic fibrosis only if both copies of the cystic fibrosis gene have a mutation.

Inheritance: Cystic fibrosis is a recessive disorder.Diagnosis: doctors use a sweat test to measure the

amount of salt (sodium chloride) in a person's sweat.Treatment: Chest physical therapy, Inhaled antibiotics ,

and Gene therapy How common it is: About 2,500 babies are born with

cystic fibrosis in the U.S. each year.

Tay –sachs diseasesDefinition: Tay-Sachs disease (Hexosaminidase A

deficiency) is a progressive fatal genetic condition that affects the nerve cells in the brain

Causes: All people have two copies of the Tay-Sachs gene (HEXA). Tay-Sachs occurs when neither of a person’s HEXA genes is working properly because of a mutation (harmful change).

Inheritance: is a rare autosomal recessive genetic disorder.Symptoms: muscle weakness, low muscle tone, an

increased startle response and sudden contractions of large muscles.

Diagnosis: A blood test .Treatment: there is no cure for Tay-Sachs disease itself.

Treatment targets controlling some of the symptoms – such as providing anticonvulsants to control seizures and proper nutrition and hydration and other comfort measures.

The HEXA gene is located on the long (q) arm of human chromosome 15, between positions 23 and 24.

Kartagener syndromeDefinition: Kartagener syndrome, a type of primary ciliary

dyskinesia, is an inherited disorder of special cells called cilia.Causes: In primary ciliary dyskinesia, the cilia are defective

and don't work properly. This means that mucus and bacteria in the lungs can't be expelled, and as a result, frequent lung infections (such as pneumonia) develop.

How common it: Kartagener syndrome is estimated to occur in 1 per 32,000 live births, and affects both males and females.

Inheritance: it is inherited in an autosomal dominant fashion.Symptoms: Chronic sinus infection, Frequent lung infections,

such as pneumonia and bronchitis, Bronchiectasis- lung damage from frequent infections, Frequent ear infections.

Diagnosis: Chest x-ray or computed tomography (CT) scanTreatment: Antibiotics can relieve sinusitis, and inhaled

medications and respiratory therapy can help if chronic lung disease develops.