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1 PKU; Phenylketonuria Phenylketonuria (PKU) is a rare condition in which a baby is born without the ability to properly break down an amino acid called phenylalanine. Phenylketonuria (PKU) is inherited, which means it is passed down through families. Both parents must pass on the defective gene in order for a baby to have the condition. This is called an autosomal recessive trait. Phenylalanine plays a role in the body's production of melanin, the pigment responsible for skin and hair color. Therefore, infants with the condition often have lighter skin, hair, and eyes than brothers or sisters without the disease. Other symptoms may include: Delayed mental and social skills Head size significantly below normal Hyperactivity Jerking movements of the arms or legs Intellectual disability Seizures Skin rashes Tremors Unusual positioning of hands PKU can be easily detected with a simple blood test. All states in the US require a PKU screening test for all newborns as part of the newborn screening panel. The test is generally done by taking a few drops of blood from the baby before the baby leaves the hospital. PKU is a treatable disease. involves a diet that is extremely low in phenylalanine, particularly when the child is growing. The diet must be strictly followed. This requires close supervision by a registered dietitian or doctor, and cooperation of the parent and child. Those who continue the diet into adulthood have better physical and mental health. Diet for life has become the standard recommended by most experts. This is especially important before conception and throughout pregnancy. Phenylalanine occurs in significant amounts in milk, eggs, and other common foods. The artificial sweetener NutraSweet (aspartame) also contains phenylalanine. Any products containing aspartame should be avoided. The outcome is expected to be very good if the diet is closely followed, starting shortly after the child's birth. If treatment is delayed or the condition remains untreated, brain damage will occur. ADHD (attention-deficit hyperactivity disorder) appears to be the most common problem seen in those who do not stick to a very low-phenylalanine diet. If proteins containing phenylalanine are not avoided, PKU can lead to intellectual disability by the end of the first year of life.

2 Achondroplasia Achondroplasia is a disorder of bone growth that causes the most common type of dwarfism. Achondroplasia may be inherited as an autosomal dominant trait, which means that if a child gets the defective gene from one parent, the child will have the disorder. If one parent has achondroplasia, the infant has a 50% chance of inheriting the disorder. If both parents have the condition, the infant's chances of being affected increase to 75%. However, most cases appear as spontaneous mutations. This means that two parents without achondroplasia may give birth to a baby with the condition. The typical appearance of achondroplastic dwarfism can be seen at birth. may include: Abnormal hand appearance with persistent space between the long and ring fingers Bowed legs Decreased muscle tone Disproportionately large head-to-body size difference Prominent forehead (frontal bossing) Shortened arms and legs (especially the upper arm and thigh) Short stature (significantly below the average height for a person of the same age and sex) Spinal stenosis Spine curvatures called kyphosis and lordosis During pregnancy, a prenatal ultrasound may show excessive amniotic fluid surrounding the unborn infant. Examination of the infant after birth shows increased front-to-back head size. There may be signs of hydrocephalus ("water on the brain"). X-rays of the long bones can reveal achondroplasia in the newborn. There is no specific treatment for achondroplasia. Related abnormalities, including spinal stenosis and spinal cord compression, should be treated when they cause problems. People with achondroplasia seldom reach 5 feet in height. Intelligence is in the normal range. Infants who receive the abnormal gene from both parents do not often live beyond a few months. Complications Clubbed feet Fluid buildup in the brain (hydrocephalus)

3 Cystic fibrosis Cystic fibrosis is a disease passed down through families that causes thick, sticky mucus to build up in the lungs, digestive tract, and other areas of the body. It is one of the most common chronic lung diseases in children and young adults. It is a life-threatening disorder. Cystic fibrosis (CF) is caused by a defective gene that causes the body to produce abnormally thick and sticky fluid, called mucus. This mucus builds up in the breathing passages of the lungs and in the pancreas, the organ that helps to break down and absorb food. Millions of Americans carry the defective CF gene, but do not have any symptoms. That's because a person with CF must inherit two defective CF genes -- one from each parent. An estimated 1 in 29 Caucasian Americans have the CF gene. related to the lungs and sinuses may include: Coughing or increased mucus in the sinuses or lungs Fatigue Nasal congestion caused by nasal polyps Recurrent episodes of pneumonia. in someone with cystic fibrosis include: Fever Increased coughing Increased shortness of breath Loss of appetite More sputum Sinus pain or pressure caused by infection or polyps that may be noticed later in life: Infertility (in men) Repeated inflammation of the pancreas (pancreatitis) Respiratory symptoms A blood test is available to help detect CF. The test looks for variations in a gene known to cause the disease. Other tests use to diagnose CF include: An early diagnosis of CF and a comprehensive treatment plan can improve both survival and quality of life. Follow-up and monitoring are very important. If possible, patients should be cared for at cystic fibrosis specialty clinics, which can be found in many communities. When children reach adulthood, they should transfer to a cystic fibrosis specialty center for adults. Lung problems are also treated with aerobic exercise or other therapies to thin the mucous and make it easier to cough up out of the lungs. These include a Percussion Vest, manual chest percussion, A-capella, or TheraPEP device. Prevention There is no way to prevent cystic fibrosis. Screening those with a family history of the disease may detect the cystic fibrosis gene in 60-90% of carriers, depending on the test used.

4 Down syndrome Trisomy 21 Down syndrome is a genetic condition in which a person has 47 chromosomes instead of the usual 46. In most cases, Down syndrome occurs when there is an extra copy of chromosome 21. This form of Down syndrome is called Trisomy 21. The extra chromosome causes problems with the way the body and brain develop. Down syndrome is one of the most common causes of human birth defects. Down syndrome symptoms vary from person to person and can range from mild to severe. However, children with Down syndrome have a widely recognized appearance. The head may be smaller than normal and abnormally shaped. For example, the head may be round with a flat area on the back. The inner corner of the eyes may be rounded instead of pointed. A doctor can often make an initial diagnosis of Down syndrome at birth based on how the baby looks. The doctor may hear a heart murmur when listening to the baby's chest with a stethoscope. A blood test can be done to check for the extra chromosome and confirm the diagnosis. There is no specific treatment for Down syndrome. Persons with Down syndrome are living longer than ever before. Although many children have physical and mental limitations, they can live independent and productive lives well into adulthood. About half of children with Down syndrome are born with heart problems, including atrial septal defect, ventricular septal defect, and endocardial cushion defects. Severe heart problems may lead to early death. Persons with Down syndrome have an increased risk for certain types of leukemia, which can also cause early death. The level of intellectual disability varies from patient to patient, but is usually moderate. Adults with Down syndrome have an increased risk for dementia. Complications Airway blockage during sleep Compression injury of the spinal cord Endocarditis Eye problems Frequent ear infections and increased risk of other infections Hearing loss Heart problems Gastrointestinal blockage Weakness of the back bones at the top of the neck

5 Marfan syndrome Marfan syndrome is a disorder of connective tissue, the tissue that strengthens the body's structures. Disorders of connective tissue affect the skeletal system, cardiovascular system, eyes, and skin. Marfan syndrome is caused by defects in a gene called fibrillin-1. Fibrillin-1 plays an important role as the building block for connective tissue in the body. The gene defect also causes too much growth of the long bones of the body. This causes the tall height and long arms and legs seen in people with this syndrome. How this overgrowth happens is not well understood. In most cases, Marfan syndrome is inherited in an autosomal dominant pattern. However, up to 30% of patients have no family history, which is called "sporadic." In sporadic cases, the syndrome is believed to be caused by a new gene change. People with Marfan syndrome are usually tall with long, thin arms and legs and spider-like fingers -- called arachnodactyly. When they stretch out their arms, the length of their arms is greater than their height. Other symptoms include: A chest that sinks in or sticks out -- funnel chest (pectus excavatum) or pigeon breast (pectus carinatum) Flat feet Highly arched palate and crowded teeth Hypotonia Joints that are too flexible (but the elbows may be less flexible) Learning disability Movement of the lens of the eye from its normal position (dislocation) Nearsightedness Small lower jaw (micrognathia) Spine that curves to one side (scoliosis) Thin, narrow face Vision problems should be treated when possible. Monitor for scoliosis, especially during the teenage years. Medicine to slow the heart rate may help prevent stress on the aorta. Avoid participating in contact sports to avoid injuring the aorta of the heart. Some people may need surgery to replace the aortic root and valve. People with Marfan syndrome who have heart valve conditions should take antibiotics before dental procedures to prevent endocarditis. Pregnant women with Marfan syndrome must be monitored very closely because of the increased stress on the heart and aorta. Heart-related complications may shorten the lifespan of people with this disease. However, many patients survive well into their 60s. Good care and surgery may extend the lifespan further.

6 Sickle cell anemia Anemia - sickle cell; Hemoglobin SS disease (Hb SS); Sickle cell disease Sickle cell anemia is a disease passed down through families in which red blood cells form an abnormal sickle or crescent shape. Red blood cells carry oxygen to the body and are normally shaped like a disc. Sickle cell is a codominant trait, so carriers of the recessive gene make both normal and sickled hemoglobin, but carriers do not have as many health issues. Sickle cell anemia is caused by an abnormal type of hemoglobin called hemoglobin S. Hemoglobin is a protein inside red blood cells that carries oxygen. Hemoglobin S changes the shape of red blood cells. The red blood cells become shaped like crescents or sickles. The fragile, sickle-shaped cells deliver less oxygen to the body's tissues. They can also get stuck more easily in small blood vessels, as well as break into pieces that can interrupt healthy blood flow. These problems decrease the amount of oxygen flowing to body tissues even more. Sickle cell anemia is inherited from both parents. If you inherit the sickle cell gene from only one parent, you will have sickle cell trait. People with sickle cell trait do not have the symptoms of sickle cell anemia. Sickle cell disease is much more common in people of African and Mediterranean descent. It is also seen in people from South and Central America, the Caribbean, and the Middle East. usually do not occur until after age 4 months. Almost all patients with sickle cell anemia have painful episodes (called crises), which can last from hours to days. These crises can cause pain in the bones of the back, the long bones, and the chest. Some patients have one episode every few years. Others have many episodes per year. The crises can be severe enough to require a hospital stay. The goal of treatment is to manage and control symptoms, and to limit the number of crises. Patients with sickle cell disease need ongoing treatment, even when they are not having a painful crisis. for a sickle cell crisis includes: Blood transfusions (may also be given regularly to prevent stroke) Pain medicines Plenty of fluids Bone marrow or stem cell transplants can cure sickle cell anemia. However, they are currently not an option for most patients. Sickle cell anemia patients are often unable to find well-matched stem cell donors. In the past, sickle cell patients often died between ages 20 and 40. Thanks to a better understanding and management of the disease, today patients can live into their 50s or beyond. Causes of death include organ failure and infection.

7 Tay-Sachs disease Tay-Sachs disease is a deadly disease of the nervous system passed down through families. Tay-Sachs disease is caused by a defective gene on chromosome 15. When both parents carry the defective Tay-Sachs gene, a child has a 25% chance of developing the disease. The child must receive two copies of the defective gene -- one from each parent -- in order to become sick. If only one parent passes the defective gene to the child, the child is called a carrier. He or she won't be sick, but will have the potential to pass the disease to his or her own children. Anyone can be a carrier of Tay-Sachs, but the disease is most common among the Ashkenazi Jewish population. About 1 in every 27 members of the Ashkenazi Jewish population carries the Tay-Sachs gene. Tay-Sachs has been classified into infantile, juvenile, and adult forms, depending on the symptoms and when they first appear. Most people with Tay-Sachs have the infantile form. In this form, the nerve damage usually begins while the baby is still in the womb. usually appear when the child is 3 to 6 months old. The disease tends to get worse very quickly, and the child usually dies by age 4 or 5. Late-onset Tay-Sachs disease, which affects adults, is very rare. Deafness Decreased eye contact, blindness Decreased muscle tone (loss of muscle strength) Delayed mental and social skills Dementia Increased startle reaction Irritability Listlessness Loss of motor skills Paralysis or loss of muscle function Seizures Slow growth If Tay-Sachs disease is suspected, the doctor will perform a physical examination and take a family history. Additional tests may include: Enzyme analysis of blood or body tissue for hexosaminidase levels Eye examination (reveals a cherry-red spot in the macula) There is no treatment for Tay-Sachs disease itself, only ways to make the patient more comfortable. Children with this disease have symptoms that get worse over time. They usually die by age 4 or 5. Prevention There is no known way to prevent this disorder. Genetic testing can detect if you are a carrier of the gene for this disorder.

8 Huntington's disease Huntington chorea Huntington's disease is a disorder passed down through families in which nerve cells in certain parts of the brain waste away, or degenerate. Huntington's disease is an autosomal dominant disorder that is caused by a genetic defect on chromosome 4. The defect causes a part of DNA, called a CAG repeat, to occur many more times than it is supposed to. Normally, this section of DNA is repeated 10 to 28 times. But in persons with Huntington's disease, it is repeated 36 to 120 times. As the gene is passed down through families, the number of repeats tend to get larger. The larger the number of repeats, the greater your chance of developing symptoms at an earlier age. Therefore, as the disease is passed along in families, symptoms develop at younger and younger ages. If one of your parents has Huntington's disease, you have a 50% chance of getting the gene for the disease. If you get the gene from your parents, you will develop the disease at some point in your life, and can pass it onto your children. If you do not get the gene from your parents, you cannot pass the gene onto your children. Behavior changes may occur before movement problems, and can include: Behavioral disturbances Hallucinations Irritability Moodiness Restlessness or fidgeting Paranoia Psychosis Abnormal and unusual movements include: Facial movements, including grimaces Head turning to shift eye position Quick, sudden, sometimes wild jerking movements of the arms, legs, face, and other body parts Slow, uncontrolled movements Unsteady gait Dementia that slowly gets worse, including: Disorientation or confusion Loss of judgment Loss of memory Personality changes Speech changes There is no cure for Huntington's disease, and there is no known way to stop the disease from getting worse. The goal of treatment is to slow down the symptoms and help the person function for as long and as comfortably as possible.

9 Hemophilia Hemophilia refers to a group of bleeding disorders in which it takes a long time for the blood to clot. When you bleed, the body launches a series of reactions that help the blood clot. This is called the coagulation cascade. The process involves special proteins called coagulation factors. When one or more of these clotting factors are missing, there is usually a higher chance of bleeding. Hemophilia is caused by a lack of enough factor VIII or IX. In most cases, hemophilia is passed down through families (inherited). Because it is X-linked recessive, it most often affects males. The main symptom of hemophilia is bleeding. Mild cases may go unnoticed until later in life, when they occur during surgery or after trauma. In more severe cases, serious bleeding may occur without any cause. Internal bleeding may occur anywhere. Bleeding into joints is common. Most often, hemophilia is diagnosed after a person has an abnormal bleeding episode or when there is a known family history of the condition. Standard treatment involves replacing the missing clotting factor through a vein (intravenous infusions). Diagnosing a bleeding disorder is important so that the doctor can take extra care if you need surgery, and can test or warn other family members who might be affected. Many people with hemophilia are able to lead pretty normal lives. However, some patients have major bleeding events, most commonly bleeding into the joint spaces. A small percentage of people with hemophilia may die from severe bleeding.

10 Color blindness Color blindness is the inability to see certain colors in the usual way. Color blindness occurs when there is a problem with the color-sensing granules (pigments) in certain nerve cells of the eye. These cells are called cones. They are found in the retina, the light-sensitive layer of tissue that lines the back of the eye. If just one pigment is missing, you may have trouble telling the difference between red and green. This is the most common type of color blindness. If a different pigment is missing, you may have trouble seeing blue-yellow colors. People with blue-yellow color blindness usually have problems identifying reds and greens, too. The most severe form of color blindness is achromatopsia. A person with this rare condition cannot see any color, so they see everything in shades of gray. Achromatopsia is often associated with lazy eye, nystagmus (small, jerky eye movements), severe light sensitivity, and extremely poor vision. Most color blindness is due to a genetic problem (X-linked recessive). About 1 in 10 men have some form of color blindness. Very few women are color blind. The drug hydroxychloroquine (Plaquenil) can also cause color blindness. It is used to treat rheumatoid arthritis, among other conditions. vary from person to person, but may include: Trouble seeing colors and the brightness of colors in the usual way Inability to tell the difference between shades of the same or similar colors Often, the symptoms may be so mild that some people do not know they are color blind. A parent may notice signs of color blindness when a child is learning his or her colors. Rapid, side-to-side eye movements (nystagmus) and other symptoms may occur in severe cases. Your doctor or eye specialist can check your color vision in several ways. Testing for color blindness is commonly done during an eye exam. There is no known treatment. However, there are special contact lenses and glasses that may help people with color blindness tell the difference between similar colors. Color blindness is a lifelong condition. Most people are able to adjust to it without difficulty or disability. Complications People who are colorblind may not be able to get a job that requires the ability to see colors accurately. For example, electricians (color-coded wires), painters, fashion designers (fabrics), and cooks (using the color of meat to tell whether it's done) need to be able to see colors accurately.