NOONAN SYNDROME

Noonan Syndrome is a condition affecting both children and adults, which

can cause heart defects and alter physical development. Its exact cause

remains unknown.

It is believed that 1 in 2,000 children worldwide are born with this

condition.

Many individuals do not receive adequate counselling because the wide

variety of features make it difficult to recognise.

PHYSICAL CHARACTERISTICS

Not all Noonan Syndrome children will have all of these features but will

present with some of them. They tend to become less obvious with maturity.

Facial

   Eyes  Hypertolorism-widely spaced eyes

         Ptosis-drooping eyelids

         Prominent down slanting eyes

         Many of these children have visual problems, most commonly squints

         and myopia.

   Nose  Flat broad nose bridge, especially when young.

         This can contribute to poor nose breathing.

   Mouth Pronounced top lip below a deep midline groove.

         High arched palate

         Malocclusion due to small jaw.

         Many children have delayed teething and an increased occurrence of

         dental cavities.

   Ears  Low set and tipped back

         Thick outer rim

         Turned up ear lobe

         There is a high incidence of glue ear leading to mild hearing loss.

         Sporadic occurrence of sensory neural deafness.

   Hair  Very low hairline

         Wooley hair

   Neck  Short neck

         Excess skin at back of neck - infancy

         Broad or webbed neck - childhood and adulthood.

Muscular Skeletal System

   Chest Elevated or depressed sternum

         Widely spaced nipples

         Square chest

         Sloping shoulders

   Spine Scoliosis in a minority of cases

   Elbows Cubitis valgus - increase in carrying angle of elbows

         Poor muscle tone and hyperextension of some joints are common

         features.

CARDIAC

A high proportion of Noonan Syndrome patients have an abnormal echogram.

The most common abnormalities are:

Pulmonary Valve Stenosis

A narrowing and sometimes a malformation of the valve that takes the blood

from the heart to the lungs for oxygenation. This can usually be corrected

by open heart surgery or cardiac catheterisation, the former appearing to

be the more successful in these children.

Hypertrophic Cardiomyopathy

Thickening of the heart muscles with possible disorganisation of the muscle

cells. In some cases, there appears to be a spontaneous improvement in this

condition. Drug therapy has also shown some success.

Atrial Septal Defect

A hole between the two upper chambers of the heart.

Ventricle Septal Defect

A hole between the two lower chambers of the heart.

Both these defects are usually surgically correctable.

GENITO URINARY SYSTEM

Undescended Testes

A high proportion of boys need surgical intervention for this condition.

HEMATOLOGY

Abnormal Clotting Factors

Deficiencies are common in factors VIII, IX and XII but various

deficiencies have been found.

Tendency to Bruise Easily

It is essential that these children are tested prior to surgery.

GROWTH AND PHYSICAL DEVELOPMENT

Feeding Difficulties

Poor sucking

Frequent forceful vomiting

Failure to thrive

This can lead to some of these children needing to be tube fed

Inability to tolerate solids

There appears to be a delay in co-ordination of palate and muscles of

swallowing. By school age, most of these children will have improved.

Shortness of Stature

A large proportion are at the lower end of the growth scale.

Delayed bone maturity

Delayed Puberty

A 3-4 year delay is quite common in both males and females.

Most females have a normal cycle

A delayed growth spurt in late teens or early twenties may occur.

INTELLIGENCE AND BEHAVIOUR

90% of Noonan Syndrome children are in normal schools. Some have learning

disabilities in specific areas. There does not appear to be a pattern as to

which area will present as a problem. They may be of average intelligence

but compared with siblings are usually slower in grasping concepts.

Delayed Speech-Delayed Language

Speech therapy is often necessary for these children.

Social Development

Due to their delayed puberty and short stature, some children can have

emotional difficulties during adolescence.