Biochemistry P6. Describe the suspected causes, diagnosis, effects (signs and symptoms) and usual treatments of either diabetes mellitus or under/overactive thyroid. Of any of the inborn errors of metabolism listed. For D2 provide the information above for both diabetes mellitus and under/overactive thyroid and all of the 4 inborn errors of metabolism listed. Provide details of the role of the relevant enzymes for all 4 of these errors.

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Our metabolism is in charge of the breakdown of foods which contain proteins, carbohydrates and fats in our bodies changing them into sugar and acid in order to create energy. Some people may experience problems which are known as metabolic disorders which disrupts this process and causing the body to lack or to produce too much of a particular substance.

Metabolic disorders can be developed when the liver or pancreases fails to function properly due to a disease. Examples of these disorders are diabetes, hypothyroidism and hyperthyroidism.

Diabetes is a lifelong condition which causes an individual’s blood glucose levels to become so high that they are unable to be controlled the homeostatic mechanisms within our body. There are two types of diabetes, ‘type 1 diabetes’ and ‘type 2 diabetes’. Type 1 diabetes is caused by the immune system destroying the cells in the pancreas that make insulin. This causes diabetes by leaving the body without enough insulin to function normally (autoimmune reaction). There is no specific cause of this but some triggers could be viral/bacterial infection, chemical toxins in food or an unidentified component causing the autoimmune reaction. Type 2 diabetes is caused by different factors such as family history, diet and obesity. Symptoms of both types of diabetes are the same however type 1 diabetes may take only weeks to develop whereas type 2 diabetes may take years to develop and diagnosis. The main symptoms are fatigue, blurred vision, cuts/wounds healing slow, weight loss, urinating more than usual etc. Type 1 diabetes and type 2 diabetes is diagnosed by a range of tests for instance, urine/blood tests, glycated haemoglobin (HbA1c) test. Type 1 diabetes can also be tested by antibody tests and type 2 diabetes can be tested by glucose tolerance test (GTT). There is no cure for diabetes but there is treatment and medication to maintain the health of those who suffer from the condition. Treatment for diabetes includes diet control, exercise, home blood glucose testing, and in some cases, oral medication and/or insulin. Approximately 40% of people with type 2 diabetes require insulin injections. Diabetes does not only cause impairment in the metabolism of sugars but is also associated with abnormal metabolism of fats and proteins. Therefore, all three key enzymes lipase, protease and amylase are vital in managing diabetes because they will help digest all three groups of nutrients: proteins, fats and sugars.
Hypothyroidism or also known as an underactive thyroid is where there isn’t enough of the hormones being produced. The main reason for an underactive thyroid is due to the immune system attacking the thyroid gland and damaging it or damage as a result of thyroids cancer or an overactive thyroid. Symptoms for an underactive thyroid may take time and the condition may not be diagnosed for many years. Some of these symptoms include fatigue, constipation, depression etc. In order to diagnose this condition, tests would be run for instance thyroid function tests. An underactive thyroid is usually treated by taking daily hormone replacement tablets called levothyroxine.
Hyperthyroidism or also known as an overactive thyroid is when there is too much of the hormones being produced in the body. There are several possible underlying causes, the most common being ‘Graves’ disease’, in which the body's immune system targets the thyroid gland and causes it to produce too much of the thyroid hormones. there are many symptoms resulting from this condition such as nervousness/anxiety, unexplained weight loss, swelling of thyroid gland (found in throat). In order to diagnose this condition, tests would be run for instance thyroid function tests. The treatment given for an overactive thyroid is called thionamides which stops the thyroid gland producing so much.

Metabolic disorders are caused by a genetic abnormality in which a specific enzyme is missing. This missing enzyme can result in serious harm and can also be harmless at the same time. This depends on the disorder however.
Galactosemia is an inherited disorder which causes babies within their first few weeks to lose their appetite. It’s possible they would suffer from vomiting, become jaundiced and have growth abnormalities. This is caused due to the high level if the monosaccharide galactose within the blood. The galactose 1-phosphate uridyl transferase is the enzyme in which are necessary for metabolising galactose and the lack of this caused the disorder to occur. The liver would also enlarge and within the urine, amino acids and proteins are now present. If a child with this condition doesn’t receive medical attention/treatment on time, this could lead to further develops such as within the cataracts galactose plays a role in the clear lens proteins. Other complications of this disease include brain damage, kidney damage and spleen damage. The diagnosis of Galactosemia is concluded when galactose and galactose 1-phosphate are identified within the urine. This is then further analysed and confirmed when the relevant enzyme is not present within the blood and the liver cells. It is vital that if there is a history of this condition within an individual’s family, that they and their family members be tested as soon as they are born. If a person does suffer from this condition, it’s important they don’t consume dairy products such as milk. This is due to galactose present within lactose which is found is dairy products. If a woman is pregnant and is aware that this condition runs in the family and as the baby could possibly have the condition, the pregnant woman cannot eat dairy products throughout the duration of her pregnancy.

Phenylketonuria (PKU) is an amino metabolism disorder and is a rare genetic condition. The body is unable to break down a substance called phenylalanine. This results in building up in the blood and brain. High levels of phenylalanine can damage the brain and could lead to brain damage. The symptoms of this condition are learning disabilities, behaviour problems and epilepsy.  There are different methods of diagnosing this condition. One is done by the heel prick test which is carried out during the first few weeks of a baby’s life. This test checks for range of conditions. If the illness is confirmed by the heel prick test, another test would be carried out which would determine the high phenylalanine levels then the individual would be referred to health professionals to specialise in treating for the disease.  To treat this disease, most people will suffer severe learning difficulties and would need care for the rest of their lives. The main treatment is to eat a low-protein diet such as potatoes and avoid high protein foods such as dairy products, meat etc. As these individuals wouldn’t be getting the nutrients from these foods, they would have to take amino acid supplements to ensure normal growth. Phenylalanine is usually broken down by the body by an enzyme known as phenylalanine hydroxylase however people who suffer from PKU are not able to do so because of an alternation in their DNA. This then causes phenylalanine levels in the blood to rise.
Glycogen storage disorders are a group of inherited diseases that result from the lack of one of the enzymes that are involved when changing glucose to glycogen or the breakdown of glycogen to glucose. There is over 12 different types of these disorders due to the number of different enzymes involved within the production of glycogen. Each of these disorders has different malfunctions which are low muscle tone, hypoglycemia (low blood sugar), heat intolerance etc.  The condition is diagnosed through a range of tests and if this condition runs through an individual’s family, they would be tested after they are born.  There would be blood tests carried out to test sugar levels and liver/kidney function and there would be scans such as an abdominal ultrasound scans. The treatment for these disorders all depends on as different types requires different treatment. With the majority of them, the treatments goal is to stablise blood sugar/energy levels. Individuals with these disorders would be put on a high protein diet. People who suffer from these diseases would be prone to having a low immune system and therefore would regularly take antibiotic medication to protect themselves from infections. If there is an enzyme lack in the production of glycogen, this can decrease the amount of normal glycogen produce. Low levels of glucose in the body (hypoglycemia) and a buildup of glycogen within the muscles and liver can be a result of problems in regards to the enzymes involved with the breakdown of glycogen into glucose.
Fructose intolerance is a disorder which is the result of the lack of protein needed for the breakdown of fructose, fructose is a sugar which is produced normally within the body. This disease can be inherited. The cause as well as inherited It may be somewhat self-imposed by our modern sugar-heavy diets. Humans have not yet evolved systems to cope with such high sugar consumption that is present within our society such as within in soft drinks, confectionery, desserts etc.  The symptoms for this condition includes fatigue, malabsorption issues (anemia), gastro-intestinal distress (bloating) etc. The diagnosis for this condition is carried out by either a H2 breath test, however this method is seen nowadays as non-reliable so a new alternative method of testing for the condition is done by using stool analysis. A Fructose-free or low-sugar diet is the best treatment. This is easy if you know which foods contain fructose - but many processed foods include fructose so foods such as this should be avoided. The enzyme responsible for this produce is known as aldolase B which is produced in the liver. This condition occurs when this enzyme is missing. Aldolase B is responsible for the second step in the metabolism of fructose, which breaks down the molecule fructose-1-phosphate into glyceraldehyde and dihydroxyacetone phosphate. To a lesser degree, aldolase B is also involved in the breakdown of the simple sugar glucose.

Reference list

NHSChoices Home Page. 2016. NHSChoices Home Page. [ONLINE] Available at: http://www.nhs.uk/pages/home.aspx.

Patient. 2016. Glycogen Storage Disorders. Inborn errors of metabolism | Patient. [ONLINE] Available at: http://patient.info/health/glycogen-storage-disorders-leaflet.

WebMD. 2016. Diagnosis of Diabetes. [ONLINE] Available at: http://www.webmd.com/diabetes/guide/diagnosis-diabetes.

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