Description

Noonan syndrome is a genetic condition that leaves of typical development in various parts of the body. It can affect a person in several ways, including unusual facial features, short stature, heart problems and other physical problems. It can also cause a child to develop more slowly than usual, for example, in walking, speaking, or learning new things.

A change of gene cause Noonan syndrome. A child inherits a copy of an affected gene from a parent. This is called dominant inheritance. The condition can also occur as a spontaneous change. This means that there is a family history involved.

Doctors manage the Noonan syndrome by controlling the symptoms and complications. You can use a growth hormone for the treatment of short height in some people with Noonan syndrome.

Symptoms

The symptoms of Noonan syndrome vary and range from mild to severe. These symptoms may be related to the specific gene that contains the change.

Facial features

How the face looks is a key feature that leads to a diagnosis of Noonan syndrome. The facial features may be more easily seen in infants and young children, but change with age. These distinctive characteristics, which become less clear in adults.

Noonan syndrome may include the following features:

  • The eyes are wide, tilted down and have a drooping of the eyelids. The eyes may be blue or pale green.
  • The ears are set low, and it seems that is tilted backward.
  • The nose is depressed at the top, with a wide base and rounded tips.
  • Mouth has a deep groove between the nose and the mouth and width of the peaks in the upper lip. The crease that extends from the edge of the nose to the corner of the mouth becomes deeply grooved with age. The teeth may be crooked. The interior of the roof of the mouth can be very arched. And the lower jaw may be small.
  • The facial features may appear rough, but appear sharper with age. The face may appear droopy, and not show expression.
  • The head can be large with a great front, and a low hairline at the back of the head.
  • The skin may appear thin and transparent with age.

Heart disease

Many people with Noonan syndrome are born with a heart problem that makes some of the main symptoms of the condition. This is called congenital heart disease. Also, some heart problems can occur later in life.

Some forms of congenital heart disease associated with the syndrome Noonan include:

  • Conditions of the valve. Pulmonary valve stenosis is a narrowing of the pulmonary valve. This valve is the flap of tissue that separates the right lower part of the chamber of the heart called the right ventricle — the artery that supplies blood to the lungs, called the pulmonary artery. Pulmonary valve stenosis is the most common heart problem that is seen with Noonan syndrome. It can occur with or without other heart problems.
  • Thickening of the heart muscle. Unusual growth or thickening of the heart muscle — also known as hypertrophic cardiomyopathy — it affects some people with Noonan syndrome.
  • Other heart problems. Problems with the structure of the heart, can lead to a hole in the wall that separates the heart's two lower chambers, known as ventricles. This is called a ventricular septal defect. Another defect is that sometimes you see is the narrowing of the artery that carries blood to the lungs to receive oxygen. This is called pulmonary artery stenosis. Or there may be narrowing of the main blood vessel known as the aorta, which carries blood from the heart to the rest of the body. This is called coarctation of the aorta.
  • The Irregular rhythm of the heart. This can occur with or without other problems in the structure of the heart. Most people with Noonan syndrome have a heart rhythm that is not normal.

Growth problems

Noonan syndrome can affect the typical growth. Many children with Noonan syndrome do not grow at a normal pace.

The problems may include:

  • Typical birth weight but slow growth over time.
  • Difficulties in the supply that can lead to poor nutrition and weight gain.
  • Levels of growth hormone, which may be too low.
  • Delay in the growth spurt that is usually seen during the teenage years because the bones do not reach the maximum strength or density until later.
  • Short in height as an adult, which is common, but some people with Noonan syndrome may not be a short one.

Problems with the muscles and bones

Some common problems may include:

  • A condition called pectus excavatum, where the sternum and the ribs sink too far into the chest. Also it is possible to have a pectus carinatum, where the sternum and the ribs grow outward, causing the breast to stick more than usual.
  • Nipples that are very far apart.
  • Short neck, often with more folds of skin, called the neck, webbed.
  • A column that has an unusual curve.

Learning disabilities

Noonan syndrome does not affect intelligence of the majority of the people who have the disease. But they may have:

  • An increased risk of learning disabilities and mild intellectual disability.
  • A wide range of mental, emotional and behavioral problems that are generally mild.
  • Vision or hearing problems can make it more difficult to learn.

Eye conditions

The common symptoms of Noonan syndrome are the eyes and the eyelids are unusual, including:

  • Problems with the muscles of the eye, such as cross-eye, also known as strabismus.
  • Of refraction of the problems, which means that the cornea or the crystalline lens is in the form of an egg with two curves that do not match. This can cause blurry or distorted vision, or make it hard to see things up close or far away.
  • The rapid movement of the eyeballs, also known as nystagmus.
  • The waterfalls, which make the eye cloudy.

Hearing problems

Noonan syndrome can cause hearing problems due to nerves or by a bone of the inner ear structure that is not typical.

Bleeding problems

Noonan syndrome can cause problems with bleeding and bruising. That is because the blood of some people with Noonan syndrome does not clot properly and can have low levels of proteins that are necessary for the formation of blood clots. So you bleed more than usual.

Lymphatic conditions

Noonan syndrome can cause problems with the lymphatic system, which drains the excess fluid from the body and helps to fight the infection. These problems:

  • It can appear before or after the birth or onset in adolescence or in adulthood. Some children are born with swelling of the hands, the feet and the fabric of the neck.
  • You can focus on a particular area of the body or be generalized.
  • Most commonly cause excessive accumulation of fluid in the back of the hands or the top of the foot. This accumulation of fluid is called lymphedema.

Genital and kidney conditions

Many people with Noonan syndrome have problems with their genitals and kidneys:

  • The testicles. It is common that males with Noonan syndrome have undescended testes. These are the testicles that have not moved in the correct position in the bag of skin hanging below the penis called the scrotum.
  • Puberty. Puberty is delayed in males and females.
  • Of fertility. For most women, the Noonan syndrome does not affect your ability to get pregnant. But the fertility in men do not develop as expected, often due to the lack of descent of the testes.
  • Kidneys. Kidney problems in general are mild and are not common.

Skin conditions

People with Noonan syndrome may have skin conditions. Can have several problems that affect the color and texture of the skin. They may also have thick or sparse hair.

When to see a doctor

Sometimes the symptoms of Noonan syndrome can be difficult to see. If you suspect that you or your child may have this condition, talk to your primary care professional or your child's pediatrician. You may be referred to a genetic specialist or a specialist in disorders of the heart or another type of doctor, depending on the symptoms.

If your unborn child is at risk due to family history of Noonan syndrome, tests may be able to do before birth.

Causes

A change in one or more genes may cause Noonan syndrome. The changes in these genes produce proteins that are always active. Because these genes play a role in how tissues are formed in the body, this constant activation of the protein disrupts the normal process of cell growth and division.

The changes in the genes that cause Noonan syndrome can be:

  • Legacy. Children who have a parent with Noonan syndrome who carries the mutated gene have a 50% chance of developing the disease. This is called an autosomal dominant pattern of inheritance.
  • Random. Noonan syndrome can develop in a child because of a new mutation — that is, the child does not inherit the gene from one parent. This is known as a de novo genetic condition.

In some cases, the cause of Noonan syndrome, is not known.

Risk factors

A father of a family with Noonan syndrome has a 50% chance of passing the mutated gene to a child. The child who inherits the spot gene may or may not have more symptoms than parents that are affected.

Complications

The complications of Noonan syndrome can arise that may need attention, including:

  • Delays in the development. Children with Noonan syndrome may be slow to develop in comparison with other children of their age. For example, they may be behind in learning to talk or walk or learning things in school. A plan is necessary to provide for the children in the area of development and learning, and educational needs.
  • Bleeding and bruising. Sometimes the bleeding is common problem in people with Noonan syndrome is not until you have dental work or surgery.
  • The accumulation of fluid. Called lymphedema, this complication involves too much fluid that accumulates in the various areas of the body. Sometimes, the liquid can collect in the space around the lungs and the heart.
  • Urinary tract problems. A structure of the kidney that is not typical may increase the risk of urinary tract infections.
  • Fertility problems. Males may have a low sperm count and other fertility problems due to the lack of descent of the testes, or testicles that do not work correctly.
  • Increased risk of cancer. There may be an increased risk of developing certain types of cancer, such as leukemia or certain types of tumors.

Prevention

If you have a family history of Noonan syndrome, talk with your doctor or health care team about the benefits of genetic counseling before they have children. Genetic testing can detect the Noonan syndrome.

If the Noonan syndrome is detected early, it is possible that appropriate and ongoing care can reduce complications such as heart disease.

Diagnosis

A doctor usually diagnoses of Noonan syndrome, after seeing some of the main signs. But this can be difficult because some of the features of the condition are not easily seen and are difficult to find. Sometimes, the Noonan syndrome is not until adulthood, after a person has a child that is most clearly affected by the disease. Genetic testing can confirm a diagnosis.

If there is evidence of problems with the heart, the cardiologist can find out the type and how severe it is.

Treatment

Although there is no cure for the Noonan syndrome, treatment can help lessen its effects. The earlier a diagnosis is made and treatment is started, the greater the benefits.

The treatment for Noonan syndrome depends on the symptoms and the complications and the degree of severity. Many of the diseases and physical problems are treated in the same way as you would for any other person. Given the many problems with this condition, a coordinated team approach is best.

The recommended approaches may include:

  • Treatment for the heart. Certain medications can treat certain types of heart problems. If there is a problem with the heart valves, surgery may be needed. The doctor may also recommend that the function of the heart is looked at from time to time.
  • The treatment of the low rate of growth. A healthcare professional should measure the height of three times a year up to 3 years of age, and then once a year until adulthood. This will ensure that your child is growing. To find out if there is a problem with the nutrition, blood tests may be ordered. If your child's growth hormone levels are not high enough, growth hormone therapy may be a treatment option.
  • The management of learning disabilities. For the early childhood developmental delays, ask your doctor or health care professional about the programs of child stimulation. Physical and speech therapies may be needed. In some cases, special education and teaching strategies tailored to the needs of your child may be appropriate.
  • The vision and hearing of the treatments. Eye exams are recommended at least every two years. Glasses can only treat the majority of eye problems. Surgery may be required for some conditions, such as cataracts. The hearing test is recommended annually for children.
  • Treatment for bleeding and bruising. If there is a history of easy bruising or bleeding problems, do not use aspirin and aspirin-containing products. In some cases, doctors may prescribe medications that help the blood to clot. Let health professionals know about the problems with bleeding and bruising prior to any procedure.
  • The treatment for fluid buildup. Accumulation of fluid in the body may or may not need treatment. Talk with your doctor or health care team about this. It is possible to suggest certain steps to take.
  • The treatment for genital problems. If one or both testicles have not entered into the appropriate position within the first few months of life, your child may need surgery.

Other evaluations and regular follow-up care may be needed. This depends on specific issues. Any person with Noonan syndrome should have follow-up care from time to time on a continuous basis.

Coping and support

There are support groups for people with Noonan syndrome and their families. Talk with your health care team about finding a support group in your area. Also, ask about the resources on the internet that you can rely on and direct you to local support groups and information about Noonan syndrome.

Preparing for your appointment

If you believe you or your child may have Noonan syndrome, the first step may be to see your primary care doctor or your child's pediatrician. But depending on the symptoms, a specialist may be recommended — for example, a doctor who specializes in heart problems, or genetics.

Here's some information to help you prepare for your appointment. If possible, bring a family member or a friend with you. A companion of confidence can help you remember the information, and provide emotional support.

What you can do

Before the appointment, make a list of:

  • The symptoms that worry you.
  • Any type of medicines, including vitamins, herbs, non-prescription drugs, or supplements, and dosage.
  • Questions to ask the doctor to make the most of your appointment.

Some questions could include:

  • The symptoms indicate that the Noonan syndrome?
  • What tests can confirm the diagnosis?
  • There are other possible causes?
  • What other problems can occur due to Noonan syndrome?
  • How these problems can be treated and managed?
  • There are options to the primary approach you're suggesting?
  • Do you recommended to consult a specialist?
  • Are there brochures or other printed material I can have? What sites do you recommend?

Do not hesitate to ask questions during your appointment.

What to expect from your doctor

Your doctor may ask you questions such as:

  • When did you first notice that something may be wrong?
  • What symptoms have you noticed?
  • Do you have any family history of Noonan syndrome?
  • Do you have any family members who have had heart disease since birth or bleeding problems?

Be prepared to answer questions, so you will have time to talk about what is most important to you.

Symptoms and treatment of Noonan syndrome