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Genetic disorders are health conditions caused by changes (also called mutations or variants) in your genes. Genes are parts of DNA found in your cells that carry instructions for how your body grows, develops, and functions. Many genes tell your body how to make proteins, which are needed for your body to work properly.

A genetic disorder happens when a gene variant changes how a protein is made. The variant may cause the protein to work poorly or not be made at all. If genes don't make the right proteins, or don't make them correctly, it can lead to a genetic disorder.

Not all gene changes cause disease. Often, these changes have no effect. But sometimes, even a small change in DNA can affect how proteins are made.

Gene variants can be grouped into two main types:

• Inherited variants (also called germline variants) are passed down from your parents. They come from egg or sperm cells.
• Non-inherited (also called somatic variants) are not passed down from your parents. They happen during your lifetime. They may be caused by things like harmful chemicals or ultraviolet (UV) rays from the sun.

Genetic disorders may be caused by:

• Single gene disorders are caused by changes in one gene. Examples can include sickle cell anemia, where a change in a single gene can cause the condition, and Charcot-Marie-Tooth disease, where a variant in one of many different genes can cause the condition.
• Chromosomal disorders are caused by missing, extra, or altered chromosomes. Chromosomes are structures that carry genes. These disorders involve changes in the number of chromosomes people have or changes in the structure of one or more chromosomes. An example is Down syndrome, which is caused by an extra copy of chromosome 21.
• Complex (multifactorial) disorders are caused by changes in many genes. Each change alone may not cause the disease, but together they increase the risk. Lifestyle and environmental factors, such as exercise, diet, or exposure to pollutants, also play a role. Colon cancer is an example.

Some genetic conditions are passed down through families (inherited) in one of several patterns, depending on the specific gene involved.

Patterns of inheritance can include:

• Dominant means you only need one changed gene to cause the condition.
• Recessive means you need two changed copies of the gene (one from each parent) for the condition to occur.
• X-linked conditions involve genes located on the X chromosome. These conditions often affect males more frequently.
• Mitochondrial conditions are passed down by the mother.

Your health care provider may check for a genetic condition based on:

• A physical examination.
• Your personal medical history.
• Your family health history.
• Laboratory tests, including genetic testing.

NIH: National Library of Medicine

Congenital heart defects (CHDs) are problems with the structure of the heart. "Congenital" means that that the problems are present at birth. These defects happen when a fetus's heart doesn't develop normally during pregnancy. Congenital heart defects are the most common type of birth defect.

Congenital heart defects can change the way the heart pumps blood. They may make blood flow too slowly, go the wrong way, or block it completely.

There are many types of congenital heart defects. They can happen in one or more parts of the heart. The most common types are:

• Septal defects ("hole in the heart") - openings in the wall between the left and right sides of the heart
• Heart valve defects - problems with the valves that control the flow of blood through the heart
• Defects in the large blood vessels that carry blood in and out of the heart

Congenital heart defects can range from very mild problems that never need treatment to life-threatening problems at birth. The most serious congenital heart defects are called critical congenital heart disease. Babies with these defects usually need surgery in the first year of life. But the symptoms of milder heart defects may not show up until childhood or adulthood.

Researchers often don't know what causes congenital heart defects. They do know that changes in a baby's genes sometimes cause a heart defect. The changed genes may come from the parents, or the changes may happen during pregnancy.

Several things may increase the chance that your baby has a congenital heart defect, such as:

• Your health before and during pregnancy, including:
  • Having diabetes before pregnancy or developing it in the first 3 months of pregnancy (diabetes that develops later in pregnancy isn't a major risk for heart defects). Carefully controlling your blood glucose, also called blood sugar, before and during pregnancy can lower your baby's risk of congenital heart defects.
  • Having phenylketonuria (PKU), a rare inherited disorder that affects how the body uses a protein in foods. If you have PKU, eating a low-protein diet before getting pregnant can lower your baby's risk of having a congenital heart defect.
  • Having rubella (German measles) during pregnancy.
• Your contact with certain substances during pregnancy, including:
  • Smoking or secondhand smoke (breathing smoke from another smoker).
  • Certain medicines, such as angiotensin-converting (ACE) inhibitors for high blood pressure and retinoic acids for acne. If you're pregnant or plan to get pregnant, talk with your health care provider about all the medicines you take.
• Your family history and genetics. In most cases, congenital heart defects don't run in families. But your chance of having a baby with a congenital heart defect does go up if you or the other parent has a congenital heart defect, or if you already have a child with a congenital heart defect.

Congenital heart defects don't cause pain. The signs and symptoms are different, depending on the type and number of defects and how serious they are.

Common signs and symptoms of congenital heart defects include:

• Cyanosis - a bluish color to the skin, lips, and fingernails. It happens when there isn't enough oxygen in the blood.
• Fatigue - your baby may be unusually sleepy and may become very tired during feedings.
• Poor blood flow.
• Fast or difficult breathing.
• Heart murmur - an unusual sound between heartbeats.

Congenital heart defects don't always cause other problems. If they do, which problems you have would depend on the type and number of defects and how serious the defects are.

Children with congenital heart defects are more likely to:

• Be smaller than other children
• Have problems or delays in mental, and emotional growth, and behavior, such as:
  • Speech and language problems
  • Attention deficit hyperactivity disorder (ADHD)

People with congenital heart defects may develop other health conditions, including:

• Endocarditis - an infection of lining of the heart and valves
• Arrhythmia - a problem with the rate or rhythm of your heartbeat
• Heart failure - when your heart can't pump enough blood to the body
• Pulmonary hypertension - high blood pressure in your lungs
• Kidney and liver disease

• Before a baby is born, your provider may use ultrasound pictures of the fetus's heart to look for heart defects. This is called a fetal echocardiogram. It's done between weeks 18 and 22 of pregnancy.
• During the first few days after birth, all newborns are checked for congenital heart defects. A pulse oximeter is clipped to your baby's hands or feet to measure blood oxygen. If it shows low levels of blood oxygen, more tests will be needed to find out if your baby has a heart defect.
• To diagnose congenital heart defects in babies, children, and adults, a provider may use many tools, including:
  • A physical exam.
  • Certain heart tests to see how the heart is working.
  • Genetic testing to see if certain gene problems caused the defect.

Treatment depends on the type of congenital heart defect and how serious it is. Possible treatments include:

• Cardiac catheterization to repair simple defects, such as a small hole in the inside wall of the heart. A catheterization uses a thin tube guided through a vein and into the heart.
• Heart surgery may be needed to:
  • Repair defects in the heart and blood vessels.
  • Repair or replace a heart valve.
  • Place a device in the chest to help the heart pump blood.
  • Do a heart transplant
• Medicine is often used if your baby has a specific type of congenital heart defect called patent ductus arteriosus.

All children and adults who have congenital heart defects need regular follow-up care from a cardiologist (a doctor who specializes in heart diseases) throughout their life, even if their defect was repaired.

Some people may need several heart surgeries or catheterizations over the years. They may also need to take medicines to help their hearts work as well as possible.

NIH: National Heart, Lung, and Blood Institute

Craniofacial is a medical term that relates to the bones of the skull and face. Craniofacial abnormalities are birth defects of the face or head. Some, like cleft lip and palate, are among the most common of all birth defects. Others are very rare. Most of them affect how a person's face or head looks. These conditions may also affect other parts of the body.

Treatment depends on the type of problem. Plastic and reconstructive surgery may help the person's appearance.

Does your child seem much shorter - or much taller - than other kids his or her age? It could be normal. Some children may be small for their age but still be developing normally. Some children are short or tall because their parents are.

But some children have growth disorders. Growth disorders are problems that prevent children from developing normal height, weight, sexual maturity or other features.

Very slow or very fast growth can sometimes signal a gland problem or disease.

The pituitary gland makes growth hormone, which stimulates the growth of bone and other tissues. Children who have too little of it may be very short. Treatment with growth hormone can stimulate growth.

People can also have too much growth hormone. Usually the cause is a pituitary gland tumor, which is not cancer. Too much growth hormone can cause gigantism in children, where their bones and their body grow too much. In adults, it can cause acromegaly, which makes the hands, feet and face larger than normal. Possible treatments include surgery to remove the tumor, medicines, and radiation therapy.

Pigmentation means coloring. Skin pigmentation disorders affect the color of your skin. Your skin gets its color from a pigment called melanin. Special cells in the skin make melanin. When these cells become damaged or unhealthy, it affects melanin production. Some pigmentation disorders affect just patches of skin. Others affect your entire body.

If your body makes too much melanin, your skin gets darker. Pregnancy, Addison's disease, and sun exposure all can make your skin darker. If your body makes too little melanin, your skin gets lighter. Vitiligo is a condition that causes patches of light skin. Albinism is a genetic condition affecting a person's skin. A person with albinism may have no color, lighter than normal skin color, or patchy missing skin color. Infections, blisters and burns can also cause lighter skin.