A hereditary disease is a disease that is passed from one generation to the next through genes. Genes are part of DNA. That is why it can also be called a genetic disease. We know well the hereditary risk in diabetes, coronary heart diseases, breast cancer, ovarian cancer and colon cancer very clearly. The corresponding genes can be identified and estimated to calculate the increased risk. At the same time we should not forget that lifestyle, overweight or obesity, alcohol and tobacco use and no or little physical activity play a vital role in many diseases. Along with these the environmental and occupational exposure to toxins, poisons and chemicals increase also the total risk of many diseases.

Thousands of genetic disorders are already known and it is sure the research will find more in the future too. Few important hereditary diseases are given below and they include:

• Achromatopsia - the inability to perceive color and to achieve satisfactory visual acuity at high light levels
• Adrenal Hypoplasia Congenita - reduced function of adrenal gland; mainly males are affected
• Adrenoleukodystrophy or Siemerling-Creutzfeldt Disease or Schilder's disease - progressive brain damage
• Aicardi Syndrome - partial or complete absence of a key structure in brain, the corpus callosum
• Albinism/Hypopigmentation - little or no melanin pigment in eyes, skin and hair
• Alexander Disease - neurodegenerative disease which destroys myelin
• Alpers' Disease or progressive neuronal degeneration of childhood with liver disease (PNDC) or Alpers-Huttenlocher syndrome - progressive neurological degenerative disease that severely affects the brain and liver
• Alpha-1 Antitrypsin Deficiency - decreased A1AT activity in blood & lungs; most common among whites
• Alzheimer's disease – a degenerative brain disease that causes problems with memory, thinking and behavior
• Amblyopia or lazy eye (poor or indistinct vision or out of proportion to associated structural abnormalities in an eye that is otherwise physically normal)
• Angelman Syndrome - primarily affects the nervous system; this condition include developmental delay, intellectual disability, severe speech impairment, and problems with movement and balance. Most affected children also have recurrent epilepsy seizures and a small head size
• Anencephaly - a condition present at birth that affects the formation of the brain and the skull bones that surround the head
• Aniridia - underdevelopment or absence of the eye's iris
• Anophthalmia - congenital absence of the globe and eye tissue from the orbit in one or both eyes
• Ataxia Telangiectasia - affects the nervous system, immune system, and other body systems; characterized by progressive difficulty with coordinating movements beginning in early childhood, usually before age 5
• Autism - usually first diagnosed in early childhood; brain development disorder with symptoms that involve communication, social interactions and repetitive behaviors
• Bardet-Biedl Syndrome - affects the brain and can cause multiple physical problems including a deterioration of the intellect and neurological functions. It sometimes affects eyesight, a degeneration of light-sensitive cells in the periphery of the retina and causes night blindness, tunnel vision, decreased visual acuity, and extreme sensitivity of the eyes to light. Other symptoms of Bardet-Biedl syndrome may include extra toes and/or fingers, mental retardation, kidney disease and obesity
• Barth Syndrome - a serious X-linked genetic disorder, primarily affecting males. It is caused by a mutation in the tafazzin gene resulting in an inborn error of lipid metabolism
• Batten Disease - a fatal, inherited disorder of the nervous system that begins in childhood
• Best's Disease - a genetic disease that causes blindness by destroying the macula in the center of the retina
• Bipolar Disorder or manic depression - psychiatric mood disorders defined by the presence of one or more episodes of abnormally elevated energy levels, cognition, and mood with or without one or more depressive episodes. The elevated moods are clinically referred to as mania or, if milder, hypomania
• Bloom Syndrome - characterized by a high frequency of breaks and rearrangements chromosomes. People with Bloom syndrome are much smaller than average, and often have a high-pitched voice and characteristic facial features including a long, narrow face; small lower jaw; and prominent nose and ears. They tend to develop pigmentation changes and dilated blood vessels in the skin, particularly in response to sun exposure
• Branchio-Oto-Renal Syndrome - an autosomal dominant condition characterized by ear abnormalities, hearing loss, cysts in the neck, and kidney problems
• Canavan Syndrome - an inherited disorder that causes progressive damage to nerve cells in the brain
• Charcot-Marie-Tooth Disease or hereditary motor and sensory neuropathy - affects the nerves in your arms and legs; loss of muscle tissue and touch sensation
• Cleft Lip/Cleft Palate - birth defects in which the tissues of the mouth or lip don't form properly during fetal development
• Coffin Lowry Syndrome - head/facial and skeletal abnormalities, mental retardation and delayed development
• Coloboma - a hole in one of the structures of the eye, such as the iris, retina, choroid or optic disc
• Color Blindness - major types are red-green color vision defects, blue-yellow color vision defects and a complete absence of color vision.
• Congenital Heart Defects - a defect in the structure of the heart and great vessels which is present at birth
• Congenital Hip Dysplasia - an abnormal formation of the hip joint in which the ball at the top of the thighbone is not stable in the socket, dislocated
• Connective Tissue Disorders – a disorder that change the look and growth of skin, bones, joints, heart, blood vessels, lungs, eyes, and ears. Can change how these tissues work
• Cooley's Anemia/ Thalassemia - caused by mutations in the beta chain of the hemoglobin molecule
• Corneal Dystrophy - one or more parts of the cornea lose their normal clarity due to a buildup of cloudy material
• Cornelia de Lange Syndrome - can lead to severe developmental anomalies. It affects both the physical and mental development of a child
• Cystic Fibrosis or mucoviscidosis - a common disease which affects the entire body, causing progressive disability and often early death
• Cystinosis - a metabolic disease in which the amino acid cystine gets into the cells, but has no transporter to bring it out and the cell crystallizes causing early cell death
• Developmental Disabilities - birth defects that cause lifelong problems
• Diabetes - metabolic diseases in with high blood sugar
• Down Syndrome - a chromosomal disorder caused by the presence of all or part of an extra 21st chromosome; impairment of cognitive ability, physical growth and facial appearance
• Duane Syndrome - a rare, congenital eye movement disorder most commonly characterized by the inability of the eye to move outwards
• Ehlers-Danlos Syndrome - inherited disorders that weaken connective tissues
• Epidermolysis Bullosa - an inherited connective tissue disease causing blisters in the skin and mucosal membranes
• Familial Dysautonomia - affects the development and survival of certain nerve cells
• Familial Mediterranean Fever - recurrent attacks of fever, inflammation of the abdominal lining, the lining surrounding the lungs, painful, swollen joints and a characteristic ankle rash
• Fanconi Anemia - aninherited blood disorder that leads to bone marrow failure and can affect many of the body's organs, tissues, and systems
• Fibrodysplasia Ossificans Progressiva - disorder in which muscle tissue and connective tissue such as tendons and ligaments are gradually replaced by bone, forming bone outside the skeleton
• Fragile X Syndrome – an inherited mental impairment; can range from learning disabilities to more severe cognitive or intellectual disabilities. It is the most common known cause of autism or "autistic-like" behaviors
• G6PD (Glucose-6-Phosphate Dehydrogenase) Deficiency Anemia - the most common human enzyme defect
• Galactosemia - a metabolic disorder that affects the ability to metabolize the sugar galactose
• Gaucher Disease - a genetic disease in which a lipids (fats) accumulates in cells and certain organs; deficiency of the enzyme glucocerebrosidase
• Gilbert's Syndrome - a common, mild liver disorder in which the liver doesn't properly process bilirubin. Bilirubin is the breakdown product of red blood cells
• Glaucoma - leads to blindness by damaging the optic nerve
• Hemochromatosis - excessive absorption of dietary iron with deposits of iron in the body
• Hemoglobin C Disease - an autosomal recessive disorder that causes mild hemolytic anemia
• Hemophilia/Bleeding Disorders - inefficient control over blood clotting or coagulation
• Hirschsprung's Disease - a disease of the large intestine that causes severe constipation or intestinal obstruction
• Homocystinuria - disorder of the metabolism of the amino acid methionine
• Huntington's Disease - a disorder passed down through families in which certain nerve cells in the brain waste away, or degenerate
• Hurler Syndrome - disorder of metabolism; deficiency of alpha-L iduronidase
• Klinefelter Syndrome - a term used to describe males who have an extra X chromosome in most of their cells, XXY instead of XY
• Krabbe Disease - fatal degenerative disorder of nervous system
• Leber Congenital Amaurosis - a degenerative disease that results in a severe loss of vision
• Leukodystrophies - are rare diseases that affect the cells of the brain, specifically the myelin sheath that surrounds and protects nerve cells
• Long Q-T Syndrome - a heart rhythm disorder that can cause fast, chaotic heartbeats
• Marfan Syndrome - disorder of the connective tissue
• Marshall-Smith Syndrome - disorder characterized by advanced bone age at birth, broad forehead, prominent eyes, and small chin
• McCune-Albright Syndrome - affects the bones and color (pigmentation) of the skin
• Menkes Disease - is an inborn error of metabolism that markedly decreases the cells' ability to absorb copper
• Metabolic Disorders - metabolic disorder occurs when abnormal chemical reactions in the body disrupt metabolism
• Mitochondrial Disease - group of neuromuscular diseases caused by damage to the mitochondria-small, energy-producing structures that serve as the cells' power house
• Mucolipidoses - a group of inherited metabolic diseases that affect the body’s ability to carry out the normal turnover of various materials within cells
• Mucopolysaccharide Disorders - are a group of metabolic disorders caused by the absence or malfunctioning of lysosomal enzymes needed to break down molecules called glycosaminoglycans, the long chain carbohydrates
• Muscular Dystrophy - refers to hereditary muscle diseases that weaken the muscles that move the human body
• Neonatal Onset Multisystem Inflammatory Disease - a disorder that causes persistent inflammation and tissue damage primarily affecting the nervous system, skin, and joints
• Neurofibromatosis - growth of tumors in nerve tissues
• Niemann-Pick Disease - fatal inherited metabolic disorders
• Noonan Syndrome - a developmental disorder with unusual facial characteristics, short stature, heart defects, bleeding problems, and skeletal malformations, eye abnormalities occur and problems with language and speech
• Optic Atrophy - loss of some or most of the fibers of the optic nerve
• Osteogenesis Imperfecta - a genetic bone disorder
• Peutz-Jeghers Syndrome - development of growths called hamartomatous polyps in the gastrointestinal tract; particularly in the stomach
• Phenylketonuria (PKU) - deficiency in enzyme phenylalanine hydroxylase
• Polycystic Kidney Disease - multiple cysts in both kidneys
• Pseudoxanthoma Elasticum - deposits of calcium and other minerals in elastic fibers, which are a component of connective tissue. Connective tissue provides strength and flexibility to structures throughout the body
• Progeria - accelerated aging at an early age
• Ptosis - "drooping eyelid” is caused by weakness of the muscle responsible for raising the eyelid, damage to the nerves that control those muscles, or looseness of the skin of the upper eyelids
• Rentinitis Pigmentosa - a degenerative, inherited eye condition which affects the retina, resulting in progressive vision loss
• Scheie Syndrome - an inherited disease of metabolism in which the body cannot properly break down long chains of sugar molecules called glycosaminoglycans
• Schizophrenia - a chronic, severe, and disabling brain disorder
• Severe Combined Immunodeficiency - rare, sometimes fatal, congenital disorders characterized by little or no immune response
• Sickle Cell Anemia - abnormal, rigid, sickle shape of red blood cells
• Skeletal Dysplasias - a group of congenital abnormalities of the bone and cartilage that are characterized by short stature
• Smith-Magenis Syndrome - developmental disorder with a broad, square-shaped face with deep-set eyes, full cheeks, and a prominent lower jaw
• Spherocytosis - a genetic disorder of the red blood cell membrane clinically characterized by anemia, jaundice and enlargement of the spleen
• Spina Bifida - a developmental birth defect caused by the incomplete closure of the embryonic neural tube
• Spinocerebellar Ataxia - a degeneration of the spinal cord and the cerebellum, the small fissured mass at the base of the brain
• Stargardt Disease - inherited diseases causing light-sensitive cells in the inner back of the eye (retina) to deteriorate, particularly in the area of the macula where fine focusing occurs
• Stickler Syndrome - hereditary conditions characterized by a distinctive facial appearance, eye abnormalities, hearing loss and joint problems
• Tay-Sachs Disease - born without one of those important enzymes, Hexosaminidase A; then fatty proteins build up in the brain, they hurt the baby's sight, hearing, movement, and mental development
• Treacher Collins Syndrome - a condition that affects the development of bones and other tissues in the face
• Tuberous Sclerosis - two genetic disorders that affect the skin, brain/nervous system, kidneys, and heart, and cause tumors to grow
• Turner's Syndrome - a genetic disorder that affects a girl's development; only one X chromosome in each cell of a female
• Urea Cycle Disorder - a genetic disorder caused by a deficiency of one of the enzymes in the urea cycle which is responsible for removing ammonia from the blood stream
• Usher's Syndrome - an autosomal recessive condition that affects both hearing and vision
• Velocardiofacial Syndrome - characterized by cleft palate, heart abnormalities, learning disabilities, and over 180 other clinical findings
• von Hippel-Lindau Disease - an inherited disorder characterized by the formation of tumors and fluid-filled sacs (cysts) in many different parts of the body
• Werner Syndrome - a premature aging disease that begins in adolescence or early adulthood and results in the appearance of old age by 30-40 years of age
• Williams Syndrome - a rare neurodevelopmental disorder with "elfin" facial appearance, along with a low nasal bridge
• Xeroderma Pigmentosum - deficient ability to repair damage caused by ultraviolet (UV) light
• Triple X Syndrome - an extra X chromosome in each cell of a female with an increased risk of learning disabilities and delayed development of speech and language skills. Delayed development of motor skills (such as sitting and walking), weak muscle tone, and behavioral and emotional difficulties
• XYY Syndrome - an extra Y chromosome in each cell of a male with Learning disabilities, hyperactivity, attention deficit disorder, and minor behavioral disorders

The genes decide what we are…