Genetic Diseases and Disorders

What Is a Gene? Most living organisms are made up of cells that contain a substance called deoxyribonucleic acid (DNA). DNA is wrapped together to form structures called chromosomes. Most cells in the human body have 23 pairs of chromosomes, making a total of 46. Genes are sections or segments of DNA that are carried on the chromosomes and determine specific human characteristics. cell [sel] – клетка deoxyribonucleic acid - дезоксирибонуклеиновая кислота, ДНК

What Are Genetic Disorders? Cells can sometimes contain changes or variants in the information in their genes. This is called gene mutation, and it often occurs when cells are aging or have been exposed to certain chemicals or radiation. Fortunately, cells usually recognize these mutations and repair them by themselves. Other times, however, they can cause illnesses. And if the gene mutation exists in egg or sperm cells, c hildren can inherit the mutated gene from their parents. inherit [ ɪ n'her ɪ t] - унаследовать, перенять

Researchers have identified more than 4,000 diseases that are caused by genetic variants. On average, people probably carry from 5 to 10 variant or disease genes in their cells. Problems arise when the disease gene is dominant or when the same recessive disease gene is present on both chromosomes in a pair. Problems can also occur when several variant genes interact with each other - or with the environment - to increase susceptibility to diseases. susceptibility [sə ˌ septə'b ɪ lət ɪ ] - восприимчивость

Diabetes

What is diabetes? Diabetes is classed as a metabolism disorder. Metabolism refers to the way our bodies use digested food for energy and growth. Most of what we eat is broken down into glucose. Glucose is a form of sugar in the blood - it is the principal source of fuel for our bodies. When our food is digested the glucose makes its way into our bloodstream. However, glucose cannot enter our cells without insulin being present - insulin makes it possible for our cells to take in the glucose. metabolism [mə'tæb(ə)l ɪ z(ə)m] - метаболизм, обмен веществ digest [da ɪ ' ʤ est] - переваривать (пищу) break down - распадаться (на части) fuel [fju ː əl ], ['fjuəl] - топливо, горючее bloodstream ['bl ʌ dstri ː m] – кровоток intestine [ ɪ n'test ɪ n] - кишечник, кишки

Insulin is a hormone that is produced by the pancreas. After eating, the pancreas automatically releases an adequate quantity of insulin to move the glucose present in our blood into the cells, and lowers the blood sugar level. pancreas ['pæŋkr ɪ əs] - поджелудочная железа release [r ɪ 'li ː s] - избавлять, освобождать A person with diabetes has a condition in which the quantity of glucose in the blood is too elevated. This is because the body does not produce enough insulin, produces no insulin, or has cells that do not respond properly to the insulin the pancreas produces. This results in too much glucose building up in the blood. This excess blood glucose eventually passes out of the body in urine. So, even though the blood has plenty of glucose, the cells are not getting it for their essential energy and growth requirements. urine ['juər ɪ n] моча

Types of diabetes There are three main types of diabetes: Type 1 - You produce no insulin at all. Type 2 - You don't produce enough insulin, or your insulin is not working properly. Gestational Diabetes - You develop diabetes just during your pregnancy. Diabetes Types 1 and 2 are chronic medical conditions - this means that they are persistent and perpetual. Gestational Diabetes usually resolves itself after the birth of the child.

Symptoms of Diabetes Frequent urination Disproportionate thirst (жажда) Intense hunger Weight gain Unusual weight loss Increased fatigue Irritability (раздражительность) Blurred (неясное,туманное) vision Cuts and bruises (синяк, кровоподтёк; ушиб) don't heal (заживать) properly or quickly More skin and/or yeast (грибковые) infections Itchy (зудящая) skin Gums (десны) are red and/or swollen (опухшие) Frequent gum disease/infection Sexual dysfunction among men Numbness (нечувствительность) or tingling (покалывание, пощипывание), especially in your feet and hands

Type 1 and Type 2 diabetes last a lifetime; there is no known cure. The patient receives regular insulin, which became medically available in The treatment for a patient with Type 1 is mainly injected insulin, plus some dietary and exercise adherence. adherence [əd'h ɪ ər(ə)n(t)s] - строгое соблюдение Patients with Type 2 diabetes are usually treated with tablets, exercise and a special diet, but sometimes insulin injections are also required. Treatment

Colour blindness

What is colour blindness? The words 'colour blindness' are misleading. People who cannot see all colours are not 'blind' - they can see things as clearly as people who are not 'colour blind'. Colour blindness means that a person cannot 'see' some colours, or sees them differently to other people. Very few people who are colour blind are 'blind' to all colours. The usual colours which they see differently are greens, yellows, oranges and reds.

Colour blindness arises from the structure of the eye. In the retina at the back of the eye (the part of the eye that picks up light coming in), there are two types of light- sensitive cells called 'rod cells' (палочки) and 'cone cells (колбочки), and these react differently to light. Rod cells are very sensitive to light, and they can react to even very faint (слабый) light, but they do not 'see' different colours. Rod cells allow us to see things around us at night, but only in shades of black, grey and white. Cone cells react to brighter light, and they help us to see the detail in objects. They also pick up colours. retina ['ret ɪ nə] сетчатка pupil ['pju ː p(ə)l] зрачок lens [lenz] линза iris ['a ɪ ər ɪ s] радужка choroid - сосудистая оболочка глаза sclera ['skl ɪ ərə] склера, белочная оболочка глаза

There are three types of cone cells; ones that pick up red light, others green and others blue. By combining the messages from each set of cone cells, we get the wide range of colours that we can normally see. Someone who is colour blind lacks (не хватать, недоставать) one or more of these types of cone cells.

Most of the people with colour blindness are male – about 1 boy in 12 will be colour blind, while only about 1 girl in 400 will be colour blind. The gene for colour vision is on the X chromosome. Females have two X chromosomes and will only be colour blind if both those chromosomes are affected. Males have only one X chromosome, so they only need that chromosome to be affected – that's why colour blindness is more common in males.

Hemophilia

What Is Hemophilia? Hemophilia is a genetic disorder in which a person's blood does not clot properly. A person who has hemophilia has a tendency to bleed excessively. clot [kl ɔ t] -свёртываться, запекаться (о крови)

Types of Hemophilia A person can have one of two types of hemophilia, A or B. It depends on which clotting factor they are low on. If someone produces 1% or less of the affected factor, the case of hemophilia is called severe. Someone who produces 2% to 5% has a moderate case, and someone who produces 6% to 50% of the affected factor level is considered to have a mild case of hemophilia.

Why Do Kids Get Hemophilia? Hemophilia almost always affects boys. Why? Because the disease is an X-linked genetic disorder, passed from mother to son. If the mother carries the gene for hemophilia on one of her X chromosomes, each of her sons will have a 50% chance of having hemophilia. A mother who is a carrier also has a 50% chance of giving the faulty X chromosome to her daughter. That does not give the daughter the hemophilia disease, but it does result in the daughter becoming a hemophilia carrier.

Even kids with severe hemophilia often live long and healthy lives. A cut, a scrape or minor wound is usually no big deal for a person with hemophilia, but internal bleeding can be serious. When bleeding occurs in the joints, muscles, or internal body organs, treatment is necessary. wound [wu ː nd] рана; ранение joint [ ʤɔɪ nt] сочленение, сустав