Hoppa till huvudinnehåll

Noonans syndrom

Noonan syndrome is a condition that affects many areas of the body. It is characterised by mildly unusual facial features, short stature, heart defects, bleeding problems, skeletal malformations, and many other signs and symptoms.

Beskrivning

Noonan syndrome is a condition that affects many areas of the body. It is characterised by mildly unusual facial features, short stature, heart defects, bleeding problems, skeletal malformations, and many other signs and symptoms.

People with Noonan syndrome have distinctive facial features such as a deep groove in the area between the nose and mouth (philtrum), widely spaced eyes that are usually pale blue or blue-green in colour, and low-set ears that are rotated backward. Affected individuals may have a high arch in the roof of the mouth (high-arched palate), poor teeth alignment, and a small lower jaw (micrognathia). Many children with Noonan syndrome have a short neck, and both children and adults may have excess neck skin (also called webbing) and a low hairline at the back of the neck.

Between 50 and 70 percent of individuals with Noonan syndrome have short stature. At birth, they are usually a normal length and weight, but growth slows over time. Abnormal levels of growth hormone, a protein that is necessary for the normal growth of the body's bones and tissues, may contribute to the slow growth.

Individuals with Noonan syndrome often have either a sunken chest (pectus excavatum) or a protruding chest (pectus carinatum). Some affected people may also have an abnormal side-to-side curvature of the spine (scoliosis).

Most people with Noonan syndrome have some form of critical congenital heart disease. The most common heart defect in these individuals is a narrowing of the valve that controls blood flow from the heart to the lungs (pulmonary valve stenosis). Some have hypertrophic cardiomyopathy, which enlarges and weakens the heart muscle.

A variety of bleeding disorders have been associated with Noonan syndrome. Some affected individuals have excessive bruising, nosebleeds, or prolonged bleeding following injury or surgery. Rarely, women with Noonan syndrome who have a bleeding disorder have excessive bleeding during menstruation (menorrhagia) or childbirth.

Adolescent males with Noonan syndrome typically experience delayed puberty. They go through puberty starting at age 13 or 14 and have a reduced pubertal growth spurt that results in shortened stature. Most males with Noonan syndrome have undescended testes (cryptorchidism), which may contribute to infertility (inability to father a child) later in life. Females with Noonan syndrome can experience delayed puberty but most have normal puberty and fertility.

Noonan syndrome can cause a variety of other signs and symptoms. Most children diagnosed with Noonan syndrome have normal intelligence, but a few have special educational needs, and some have intellectual disability. Some affected individuals have vision or hearing problems. Affected infants may have feeding problems, which typically get better by age 1 or 2 years. Infants with Noonan syndrome may be born with puffy hands and feet caused by a buildup of fluid (lymphedema), which can go away on its own. Older individuals can also develop lymphedema, usually in the ankles and lower legs.

Some people with Noonan syndrome develop cancer, particularly those involving the blood-forming cells (leukemia). It has been estimated that children with Noonan syndrome have an eightfold increased risk of developing leukemia or other cancers over age-matched peers.

Noonan syndrome is one of a group of related conditions, collectively known as RASopathies. These conditions all have similar signs and symptoms and are caused by changes in the same cell signaling pathway. In addition to Noonan syndrome, the RASopathies include cardiofaciocutaneous syndrome, Costello syndrome, neurofibromatosis type 1, Legius syndrome, and Noonan syndrome with multiple lentigines.

Inheritance patterns

The source lists the following possible inheritance patterns: Autosomal dominant. More than one pattern can apply in different cases.

Other names

Familial Turner syndrome

Female pseudo-Turner syndrome

Male Turner syndrome

Noonan's syndrome

Noonan-Ehmke syndrome

NS

Pseudo-Ullrich-Turner syndrome

Turner phenotype with normal karyotype

Turner syndrome in female with X chromosome

Turner-like syndrome

Ullrich-Noonan syndrome

Related patient information and medicines

Begränsad tillväxt

Patient information leaflet

Begränsad tillväxt

Dwarfism is a medical or genetic condition which causes people to have restricted growth so that they are shorter than average. Specifically, people with dwarfism grow no higher than 4 ft 10 ins (147 cm). This is a rare genetic condition with many features i... It may also cause short stature. Noonan syndrome. A rare genetic condition causing many.

Gilberts syndrom

Patient information leaflet

Gilberts syndrom

Gilberts syndrom is due to an inherited defect in processing bilirubin in the liver. This is because bilirubin is an orangey-yellow colour. Although typically harmless, there has been some evidence found recently that Gilbert's syndrome may be associated with both good and bad health outcomes: There is some evidence for pr... However, Gilbert's.

Proctalgia fugax och anal smärta

Patient information leaflet

Proctalgia fugax och anal smärta

Proctalgia fugax is a fleeting pain in the anus. It lasts less than 20 minutes, with no symptoms whatsoever in between episodes. Levator ani syndrome is a pain which lasts for longer. Both are only diagnosed when no other cause is found. What is proctalgia fugax. Proctalgia fugax is one of a number of conditions which cause anal or rectal pain.

Nefrotiskt syndrom

Patient information leaflet

Nefrotiskt syndrom

Nefrotiskt syndrom is a condition where the 'filters' in the kidney become 'leaky' and large amounts of protein leak from the blood into the urine. The main symptom is fluid retention (oedema) which is mainly due to the low protein level in the blood. Various diseases can cause nephro... What is nephrotic syndrome. Nephrotic syndrome is not a.

Cervikal revben

Patient information leaflet

Cervikal revben

Om 1 in 100 people är born with an extra rib called a cervical rib. About 1 in 10 people who have a cervical rib develop thoracic outlet syndrome. This happens if the cervical rib squashes the nerves and blood vessels going into the arm. Treatment can include painkillers, physiotherapy and sometimes surgery to relieve the compression caused.

Oralt allergisyndrom

Patient information leaflet

Oralt allergisyndrom

Oral allergy syndrome causes symptoms around the mouth that är triggered by certain foods. It is associated with other conditions caused by plant allergies, such as hay fever and allergy to birch pollen. It's also called pollen-food syndrom... What is oral allergy syndrome. Oral allergy syndrome (OAS) is an allergic condition which causes itching.

Vidare läsning och referenser

Artikelhistorik

Informationen på denna sida är skriven och granskad av kvalificerade kliniker.
  • 18 aug 2020 | Senaste versionen
  • 1 May 2016 | Ursprungligen publicerad

Delta i konversationen

Dela dina tankar eller erfarenheter med andra i vår patientgemenskaper.

Ansvarsfriskrivning: The views expressed in the community do not represent medical advice. For any health concerns, consult your GP or healthcare provider.
influensaberättigandekontroll

Fråga, dela, anslut.

Bläddra i diskussioner, ställ frågor och dela erfarenheter inom hundratals hälsorelaterade ämnen.

Anmäl dig till Patientens nyhetsbrev

Din veckovisa dos av tydliga, pålitliga hälsoråd - skrivna för att hjälpa dig känna dig informerad, självsäker och i kontroll.

Vänligen ange en giltig e-postadress

Genom att prenumerera accepterar du våra Sekretesspolicy. Du kan avsluta prenumerationen när som helst. Vi säljer aldrig dina uppgifter.