Noonan syndrome is a genetic condition that manifests broad spectrum of congenital abnormalities which include characteristic facial features, chest deformity, short stature, congenital heart disease, kidney malformation, increased bleeding tendency etc. In short in this genetic disease there is abnormal development of various parts of body.
The disorder is caused by defect in the genes of parents. This defect is passed on to the child. Sometimes mutation can occur suddenly without any family history. Diagnosis is made from clinical features. But sometimes in mild form this can be missed. Hence besides clinical features, doctors also rely on molecular genetic tests to diagnose noonan syndrome.
There is no specific treatment evolved for this condition. Management is focused on alleviating the symptoms and attending the rising complications.
What Is The Cause Of Noonan Syndrome?
Noonan syndrome is caused by defect or mutation in genes. The defect can be in several genes. The mutation in genes causes the protein that is involved in development of organs and tissues to be overactive. The continuous over activity of protein makes normal cellular growth and division difficult. The incidence of noonan syndrome is estimated to be 1 in 2500 live births. However, in milder cases it may be more common.
The defective gene can be passed on from one parent. At least 50 percent of people suffering from noonan syndrome may have inherited the faulty gene from their parent. The parent may be suffering from the symptoms or may be just a carrier without any obvious symptoms. In some cases mutation of gene may occur spontaneously without any history of the disease is family. One of the most likely risks for development of noonan syndrome is a parent suffering from noona syndrome.
Signs And Symptoms Of Noonan Syndrome
There are great variety of signs and symptoms in individuals suffering from noonan syndrome. This is because of multiple genes that may be faulty. The characteristic feature represents the specific gene mutation. Diagnosis of the syndrome depends on identification and classical clinical features, mostly the facial features.
- Droopy eyelids
- Ear rotated backwards
- Crooked teeth
- Forehead is broad
- Short neck
- Wide base nose with marked depression on top.
- Deep grove between mouth and nose.
- Excess flap of skin on neck.
- Late onset of puberty.
- Absence of growth spurt during puberty.
- Abnormal thickening of heart muscles.
- Structural defect in heart which is apparent on radiological studies.
- Undescended testis in males leading to infertility.
- Small sized penis
- Hearing problem
- Eating difficulty
- Easy bleeding and bruising
Diagnosis And Treatment Of Noonan Syndrome
Peculiar facial features help in diagnosis of noonan syndrome. Aside of this, genetic testing, radiological examination, electrocardiogram, 2-d echocardiogram, hearing test will help to evaluate and diagnose the condition.
There is no cure for noonan syndrome since it is a genetic disorder. Treatment is hence aimed at relieving symptoms and reducing possibility of complications. For example children with short stature may be given growth hormones so to increase their height. Surgery and/ or medication may be necessary to manage heart defects. For learning difficulty various therapies may be necessary which may include physiotherapy, speech therapy, and occupational therapy.
Since there is more chance of bleeding, patient may need some medicines to that may help in blood clotting. Patient must avoid blood thinners. The child may require corrective surgery for undescended testes. Patient also needs regular examination or ear and eyes and correct if there is any abnormality noted, with right hearing aid and eye glasses.