karyotype

A birth defect is a problem that happens while a baby is developing in the mother's body. Most birth defects happen during the first 3 months of pregnancy. One out of every 33 babies in the United States is born with a birth defect.

A birth defect may affect how the body looks, works, or both. Some birth defects like cleft lip or neural tube defects are structural problems that can be easy to see. Others, like heart disease, are found using special tests. Birth defects can range from mild to severe. How a birth defect affects a child's life depends mostly on which organ or body part is involved and how severe the defect is.

For some birth defects, researchers know the cause. But for many birth defects, the exact cause is unknown. Researchers think that most birth defects are caused by a complex mix of factors, which can include:

• Genetics. One or more genes might have a change or mutation that prevents them from working properly. For example, this happens in Fragile X syndrome. With some defects, a gene or part of the gene might be missing.
• Chromosomal problems. In some cases, a chromosome or part of a chromosome might be missing. This is what happens in Turner syndrome. In other cases, such as with Down syndrome, the child has an extra chromosome.
• Exposures to medicines, chemicals, or other toxic substances. For example, alcohol misuse can cause fetal alcohol spectrum disorders.
• Infections during pregnancy. For example, infection with Zika virus during pregnancy can cause a serious defect in the brain.
• Lack of certain nutrients. Not getting enough folic acid before and during pregnancy is a key factor in causing neural tube defects.

Certain factors may increase the chances of having a baby with a birth defect, such as:

• Smoking, drinking alcohol, or taking certain "street" drugs during pregnancy
• Having certain medical conditions, such as obesity or uncontrolled diabetes, before and during pregnancy
• Taking certain medicines
• Having someone in your family with a birth defect. To learn more about your risk of having a baby with a birth defect, you can talk with a genetic counselor,
• Being an older mother, typically over the age of 34 years

Health care providers can diagnose some birth defects during pregnancy, using prenatal testing. That's why it important to get regular prenatal care.

Other birth defects may not be found until after the baby is born. Providers may find them through newborn screening. Some defects, such as club foot, are obvious right away. Other times, the health care provider may not discover a defect until later in life, when the child has symptoms.

Children with birth defects often need special care and treatments. Because the symptoms and problems caused by birth defects vary, the treatments also vary. Possible treatments may include surgery, medicines, assistive devices, physical therapy, and speech therapy.

Often, children with birth defects need a variety of services and may need to see several specialists. The primary health care provider can coordinate the special care that the child needs.

Not all birth defects can be prevented. But there are things you can do before and during pregnancy to increase your chance of having a healthy baby:

• Start prenatal care as soon as you think you might be pregnant, and see your health care provider regularly during pregnancy
• Get 400 micrograms (mcg) of folic acid every day. If possible, you should start taking it at least one month before you get pregnant.
• Don't drink alcohol, smoke, or use "street" drugs
• Talk to your health care provider about any medicines you are taking or thinking about taking. This includes prescription and over-the-counter medicines, as well as dietary or herbal supplements.
• Learn how to prevent infections during pregnancy
• If you have any medical conditions, try to get them under control before you get pregnant

Centers for Disease Control and Prevention

Your blood is living tissue made up of liquid and solids. The liquid part, called plasma, is made of water, salts and protein. Over half of your blood is plasma. The solid part of your blood contains red blood cells, white blood cells and platelets.

Blood disorders affect one or more parts of the blood and prevent your blood from doing its job. They can be acute or chronic. Many blood disorders are inherited. Other causes include other diseases, side effects of medicines, and a lack of certain nutrients in your diet.

Types of blood disorders include:

• Platelet disorders, excessive clotting, and bleeding problems, which affect how your blood clots
• Anemia, which happens when your blood does not carry enough oxygen to the rest of your body
• Cancers of the blood, such as leukemia and myeloma
• Eosinophilic disorders, which are problems with one type of white blood cell.

Cancer begins in your cells, which are the building blocks of your body. Normally, your body forms new cells as you need them, replacing old cells that die. Sometimes this process goes wrong. New cells grow even when you don't need them, and old cells don't die when they should. These extra cells can form a mass called a tumor. Tumors can be benign or malignant. Benign tumors aren't cancer while malignant ones are. Cells from malignant tumors can invade nearby tissues. They can also break away and spread to other parts of the body.

Cancer is not just one disease but many diseases. There are more than 100 different types of cancer. Most cancers are named for where they start. For example, lung cancer starts in the lung, and breast cancer starts in the breast. The spread of cancer from one part of the body to another is called metastasis. Symptoms and treatment depend on the cancer type and how advanced it is. Most treatment plans may include surgery, radiation and/or chemotherapy. Some may involve hormone therapy, immunotherapy or other types of biologic therapy, or stem cell transplantation.

NIH: National Cancer Institute

Down syndrome is a condition in which a person has an extra chromosome or an extra piece of a chromosome. This extra copy changes how a baby's body and brain develop. It can cause both mental and physical challenges during their lifetime. Even though people with Down syndrome might act and look similar, each person has different abilities.

Chromosomes are tiny "packages" in your cells that contain your genes. Genes carry information, called DNA, that controls what you look like and how your body works. People with Down syndrome have an extra copy of chromosome 21. In some cases, they may have an extra copy of part of the chromosome. Having an extra copy of a chromosome is called trisomy. So sometimes Down syndrome is also called trisomy 21.

Down syndrome is usually not inherited. It happens by chance, as an error when cells are dividing during early development of the fetus. It is not known for sure why Down syndrome occurs or how many different factors play a role.

One factor that increases the risk of having a baby with Down syndrome is the age of the mother. Women ages 35 and older are more likely to have a baby with Down syndrome.

The symptoms of Down syndrome are different in each person. And people with Down syndrome may have different problems at different times of their lives. They usually have mild to moderate intellectual disabilities. Their development is often delayed. For example, they may start talking later than other children.

Some of the common physical signs of Down syndrome include:

• A flat face
• Eyes that slant up
• A short neck
• Small hands and feet
• Poor muscle tone
• Loose joints

Many people with Down syndrome have the common physical signs and have healthy lives. But some people with Down syndrome might have one or more birth defects or other health problems. Some of the more common ones include:

• Hearing loss
• Sleep apnea (a disorder that causes you to repeatedly stop breathing during sleep)
• Ear infections
• Eye diseases
• Congenital heart defects (heart defects that are present at birth)
• Digestive problems
• Problems with the upper part of the spine
• Obesity

Health care providers can check for Down syndrome during pregnancy or after a child is born.

There are two basic types of tests that help find Down syndrome during pregnancy:

• Prenatal screening tests can show whether your unborn baby has a higher or lower chance of having Down syndrome. If a screening test shows that your baby could have Down syndrome, you'll need another test to find out for sure.
• Prenatal diagnostic tests can diagnose or rule out Down syndrome by checking the chromosomes in a sample of cells.

These tests have a small risk of causing a miscarriage, so they're often done after a screening test shows that an unborn baby could have Down syndrome.

After a baby is born, the provider may make an initial diagnosis of Down syndrome based on the physical signs of the syndrome. The provider can use a karyotype genetic test to confirm the diagnosis. The test can check for extra chromosomes in a sample of the baby's blood.

There is no single, standard treatment for Down syndrome. Treatments are based on each person's physical and intellectual needs, strengths, and limitations.

Services early in life focus on helping children with Down syndrome develop to their full potential. These services include speech, occupational, and physical therapies. They are typically offered through early intervention programs in each state. Children with Down syndrome may also need extra help or attention in school, although many children are included in regular classes.

Since people with Down syndrome can have birth defects and other health problems, they will need regular medical care. They may need to have certain extra health screenings to check for problems that happen more often in people with Down syndrome.

Centers for Disease Control and Prevention

Infertility means not being able to get pregnant after at least one year of trying (or 6 months if the woman is over age 35). If a woman keeps having miscarriages, it is also called infertility. Female infertility can result from age, physical problems, hormone problems, and lifestyle or environmental factors.

Most cases of infertility in women result from problems with producing eggs. In primary ovarian insufficiency, the ovaries stop functioning before natural menopause. In polycystic ovary syndrome (PCOS), the ovaries may not release an egg regularly or they may not release a healthy egg.

About a third of the time, infertility is because of a problem with the woman. One third of the time, it is a problem with the man. Sometimes no cause can be found.

If you think you might be infertile, see your doctor. There are tests that may tell if you have fertility problems. When it is possible to find the cause, treatments may include medicines, surgery, or assisted reproductive technologies. Happily, many couples treated for infertility are able to have babies.

Dept. of Health and Human Services Office on Women's Health

Genetic testing is a type of medical test that looks for changes in your DNA. DNA is short for deoxyribonucleic acid. It contains the genetic instructions in all living things. Genetic tests analyze your cells or tissue to look for any changes in:

• Genes, which are parts of DNA that carry the information needed to make a protein
• Chromosomes, which are thread-like structures in your cells. They contain DNA and proteins.
• Proteins, which do most of the work in your cells. Testing can look for changes in the amount and activity level of proteins. If it finds changes, it might be due to changes in your DNA.

Genetic testing may be done for many different reasons, including to:

• Find genetic diseases in unborn babies. This is one type of prenatal testing.
• Screen newborn babies for certain treatable conditions
• Lower the risk of genetic diseases in embryos that were created using assisted reproductive technology
• Find out if you carry a gene for a certain disease that could be passed on to your children. This is called carrier testing.
• See whether you are at increased risk of developing a specific disease. This may be done for a disease that runs in your family.
• Diagnose certain diseases
• Identify genetic changes that may be causing or contributing to a disease that you were already diagnosed with
• Figure out how severe a disease is
• Help guide your doctor in deciding the best medicine and dosage for you. This is called pharmacogenomic testing.

Genetic tests are often done on a blood or cheek swab sample. But they may also be done on samples of hair, saliva, skin, amniotic fluid (the fluid that surrounds a fetus during pregnancy), or other tissue. The sample is sent to a laboratory. There, a lab technician will use one of several different techniques to look for genetic changes.

The benefits of genetic testing include:

• Helping doctors make recommendations for treatment or monitoring
• Giving you more information for making decisions about your health and your family's health:
  • If you find out that you are at risk for a certain disease, you might take steps to lower that risk. For example, you may find out that you should be screened for a disease earlier and more often. Or you might decide to make healthy lifestyle changes.
  • If you find out that you are not at risk for a certain disease, then you can skip unnecessary checkups or screenings
  • A test could give you information that helps you make decisions about having children
• Identifying genetic disorders early in life so treatment can be started as soon as possible

The physical risks of the different types of genetic testing are small. But there can be emotional, social, or financial drawbacks:

• Depending on the results, you may feel angry, depressed, anxious, or guilty. This can be especially true if you are diagnosed with a disease that does not have effective treatments.
• You may be worried about genetic discrimination in employment or insurance
• Genetic testing may give you limited information about a genetic disease. For example, it cannot tell you whether you will have symptoms, how severe a disease might be, or whether a disease will get worse over time.
• Some genetic tests are expensive, and health insurance might only cover part of the cost. Or they may not cover it at all.

The decision about whether to have genetic testing is complex. In addition to discussing the test with your health care provider, you can meet with a genetic counselor. Genetic counselors have specialized degrees and experience in genetics and counseling. They can help you understand the tests and weigh the risks and benefits. If you do get a test, they can explain the results and make sure that you have the support that you need.

Klinefelter syndrome (KS) is a genetic condition that happens when a male is born with an extra copy of the X chromosome. KS can affect different stages of physical, language, and social development. It also usually causes infertility.

KS is not inherited. It's caused by a random error that happens when a sperm or egg is formed. This error causes a male to be born with an extra X chromosome.

Chromosomes are tiny "packages" in your cells that contain your genes. Genes carry information, called DNA, that controls what you look like and how your body works. Normally, you're born with a set of 46 chromosomes in each cell, two of which are the sex chromosomes. Females usually have two X chromosomes (XX), and males usually have one X and one Y (XY). In KS, the male usually has two X chromosomes and one Y (XXY).

In rare cases, a male could have XY in some cells and XXY in other cells. This is called mosaic Klinefelter syndrome. Males with mosaic Klinefelter syndrome may have fewer symptoms, depending on the number of XY cells they have in their bodies and where those cells are located.

Some males with KS may have no symptoms or very mild symptoms. So they might not know that they have KS, or they might not get diagnosed with it right away. In other cases, the symptoms can be more severe.

Boys with KS may be taller than other boys their age, with more fat around the belly. After puberty, they may have:

• Smaller testes and penis
• Breast growth (called gynecomastia)
• Less facial and body hair
• Reduced muscle tone
• Narrower shoulders and wider hips
• Weaker bones
• Decreased sexual interest
• Lower energy

Many of these symptoms happen because of low testosterone in the body. Testosterone is the main male sex hormone.

Boys with KS may also have learning or language problems. These problems may affect them socially, so they may be shy and quiet and can have trouble fitting in.

Most males with KS are infertile because they make little or no sperm.

There is no cure for KS, but treatments are available. The sooner the treatment is started, the better. If treatment is started by early puberty, it will likely help in reducing the symptoms.

Treatments for KS may include:

• Testosterone replacement therapy
• Surgery to remove or reduce breasts
• Physical, speech, behavioral, and occupational therapy

In some cases, fertility treatments may help men with KS father children.

NIH: National Institute of Child Health and Human Development

Prenatal testing provides information about your baby's health before he or she is born. Some routine tests during pregnancy also check on your health. At your first prenatal visit, your health care provider will test for a number of things, including problems with your blood, signs of infections, and whether you are immune to rubella (German measles) and chickenpox.

Throughout your pregnancy, your health care provider may suggest a number of other tests, too. Some tests are suggested for all women, such as screenings for gestational diabetes, Down syndrome, and HIV. Other tests might be offered based on your:

• Age
• Personal or family medical history
• Ethnic background
• Results of routine tests

There are two types of tests:

• Screening tests are tests that are done to see if you or your baby might have certain problems. They evaluate risk, but do not diagnose problems. If your screening test result is abnormal, it does not mean that there is a problem. It means that more information is needed. Your health care provider can explain what the test results mean and possible next steps. You may need diagnostic testing.
• Diagnostic tests show whether or not you or your baby have a certain problem.

It is your choice whether or not to get the prenatal tests. You and your health care provider can discuss the risks and benefits of the tests, and what kind of information the tests can give you. Then you can decide which ones are right for you.

Dept. of Health and Human Services Office on Women's Health

If a woman loses a pregnancy after she's past her 20th week, it's called a stillbirth. Stillbirths are due to natural causes. They can happen before delivery or during delivery. Causes include:

• Problems with the placenta, the organ that transports oxygen and nutrients to the fetus
• Genetic problems with the fetus
• Fetal infections
• Other physical problems in the fetus

In at least half of all cases, it is not possible to tell why the baby died.

If stillbirth happens before delivery, your health care provider may induce labor or perform a Cesarean section to deliver the fetus. In some cases, you can wait until you go into labor yourself. This usually happens within two weeks of stillbirth.

Counseling may help you cope with your grief. Later, if you do decide to try again, work closely with your health care provider to lower the risks. Many women who have a stillbirth go on to have healthy babies.

NIH: National Institute of Child Health and Human Development

Turner syndrome is a genetic disorder that affects a girl's development and appearance. It can also cause health problems such as infertility and heart problems.

Turner syndrome can cause many different symptoms. The symptoms may be mild for some people. But for others, Turner syndrome can cause serious health problems.

Some of the symptoms of Turner syndrome affect a person's appearance. Most people with Turner syndrome are shorter than average. They may also have physical features such as:

• A neck that is short and has extra skin (a "webbed" neck)
• A low hairline in the back
• Low-set ears
• Swollen hands and feet

People with Turner syndrome may be born with heart and kidney defects. They usually don't have typical sexual development and are infertile. They are also at risk for other health problems such as high blood pressure, type 2 diabetes, osteoporosis, and thyroid problems.

Health care providers diagnose Turner syndrome based on symptoms and a genetic blood test called a karyotype test. Sometimes it is found in prenatal testing.

There is no cure for Turner syndrome, but there are treatments for some of the symptoms:

• If they are started in early childhood, hormone injections can often increase adult height by a few inches
• Estrogen replacement therapy (ERT) can help start sexual development. It also protects against bone loss
• Assisted reproduction technologies can help some women with Turner syndrome get pregnant

People who have Turner syndrome need regular health checks. It's also important for them to have a care team that includes specialists who can treat the health problems caused by Turner syndrome.

NIH: National Institute of Child Health and Human Development