Noonan Syndrome

What is Noonan Syndrome ?

Noonan syndrome is a genetic mutation that hinders the normal growth of body parts,causesheart defects, restricts body growth, lowers intelligence, and results in unusual face formation and other physical disorders.During the conception of fetus, Noonan syndrome is caused due to the fetus acquiring a copy of mutated gene from a parent. Noonan syndrome can also occur by chance, even without any prior family history of the condition.

Medically,Noonan syndrome has no specific cure;except management of the symptoms by providing growth hormones for short stature and other required medications for related defects.

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 Noonan syndrome – Symptoms

Noonan syndrome affects a number of body systems. The associated symptoms are categorized as below:

  • Facial features: The clinical facial features of Noonan syndrome affected patients change as they grow older. Facial features of a patient at various stages are as follows:
    • Early infancy: An infant that is less than one month old may have slanting wide-set eyes, an upper lip with wide peaks and a deep groove, a short neck, low-set ears, and a low backside hairline.
    • Infancy: The affected infant may have a nose with a pressed top, a wider base and a rounded tip, as well as noticeable eyes with thick eyelids and a descending slant.
    • Childhood:The affected child lacks facial expression
    • Adolescence: Wide forehead, pointed chin, lengthy webbed neck,a sharper face, blunt eyes, and dominant neck muscles are evident.
    • Adulthood: Wrinkled and translucent skin, and visible lines running along both sides of the mouth can be observed
    • Heart disorder: About 80% of Noonan syndrome patients suffer from congenital heart disorders such as:
      • Valve disorders:  The most common heart disorder is narrowing of pulmonary valve which is the tissue of flap that separates the lower right ventricle of heart from the artery that supplies blood to the lungs.There can also beadditional related defects.
      • Structural defects: Patients may suffer from ventricular septal defect which indicates the presence of a hole in the wall that separates the lower chambers of the heart, and/or narrowing of the arteries that take blood to lungs for getting enriched with oxygen.
      • Thickening of heart muscles: About 20% of Noonan syndrome patients suffer from thickening of the cardiac muscles.
      • Growth disorder: It can result in:
        • Feeding problems
        • Poor weight upto 18 months
        • Delayed bone maturity
        • Short stature is common even though many have normal heights.
        • Vision problems include:
          • Abnormalities in eyes and eyelids
          • Varied shape and size of the eyes
          • Often, the iris iseither pale blue or green
          • Eye muscle problems such as crossed eyes with or without refractive problems such as myopia, hypermetropia, nystagmus.
          • Learning disabilities: Most children affected by Noonan syndrome have a normal lifestyle without any intellectual deficits.However, they are at a higher risk to learningproblems.
          • Musculoskeletal problems include:
            • Sunken or raised sternum are common
            • Wide –set nipples
            • Short webbed neck with extra folds is common
            • Bleeding: Most people with Noonan syndrome have excessive bleeding problem which come to light when injury or surgery takes place.
            • Skin problems: Abnormalities involving the texture and color of skin are prevalent.Individuals affected by Noonan syndrome also have coarse, curly, orscarce hair
            • Genital and kidney disorders: Male patients may develop genital and kidney conditions. Normally, kidney problems are mild and affect fewer individuals. Puberty for both genders may get delayed. However, girls will have normal fertility, but males may not experience normal fertility due to undescended testicles.
            • Lymphatic anomalies: It can affect a particular body part or the entire body. Lymphedema of the feet or hands is common

Causes 

Noonan syndrome is caused due to mutation of certain genes, seven in number as found out by scientists. It is inherited from parents who carry defective gene. It can also develop due to a new mutation that occurs in children who do not have a genetic predisposition. Children have 50% chance of developing the syndrome if any one of the parents possess the defective gene.

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The defects in the genes induce the active production of proteins which disrupt the normal cell growth process.

If Noonan syndrome occurseven after the seven genes are found to be normal, then it may indicate that an undiscovered genehas caused the syndrome.

Noonan Syndrome Treatment 

Social problems that occur due to varied deficits have to be addressed by making special arrangements for training and educating the child. The health problems are to be addressed by medical solutions as shown below:

  • Genital and urinary tract problems: Antibiotic drugs are given for urinary tract problems. For genital problems doctors advice surgery.
  • Treatment for bleeding: Avoid aspirin and aspirin content medicines. Sometimes, doctors may go for drugs that aid the clotting process
  • Lymphatic problems: It is a less common defect. If excess fluid collection takes place around the heart and lungs, then it is drained outby inserting a tube. Diet control is advised. In case of persistent swelling around the lungs and the heart, operationis recommended.
  • Heart ailments: Apart from medications, valve defects can be corrected via surgery.
  • Low growth rate: Adequate nutrition and growth hormone therapy are required if the growth hormone levels are insufficient.
  • Vision treatment: Vision test after every two years is recommended. Vision problems can be corrected via use of prescription glasses or surgery, if needed.

Noonan Syndrome Pictures

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