The previous page describes the situation in the full Turner Syndrome karyotype, written XO. Sometimes, only a proportion of cells has this chromosome compliment, the remaining cells have the normal female XX chromosomes. This condition is referred to as Mosaic Turner Syndrome. Girls with mosaic forms of Turner Syndrome often have fewer if of the physical features and may be more likely to show signs of sexual development without treatment, although they are unlikely to develop fully and to menstruate. The extent of the short stature, however, is not related to the specific karyotype. If follows that any girl with short stature of unknown cause should have a chromosome analysis done.
Further contact : Dr. I.P.S. Kochar
NOONAM SYNDROME
Diagnosis : 70% by primary school age
Treatment : GH in trials
Noonan Syndrome is a common condition, estimated to occur in approximately 1/2000 of the population. The physical appearance has characteristic facial and body features, dysmorphic signs and short stature. In addition these individuals often have abnormalities of blood clotting and congenital heart defects. The latter usually involves abnormatlities of the right side of the heart or of the heart muscle. All children with Noonan Syndrome should see a cardiologist and have an ultrasound examination of the heart chambers and valves. They may also have abnormalities of blood clotting.
 In many ways Noonan Syndrome resembles Turner Syndrome, although it occurs in both boys and girls. It is thought that there is a chromosomal abnormality although this has not yet been identified. This specific gene for Noonan Syndrome has not been identified yet but it would be relevant to seek specialist genetic advice to both confirm the diagnosis and to determine the risk of recurrence in further offspring.
Children with Noonan Syndrome are short, although the range of heights does overlap into the normal range. They commonly have delayed puberty, which may require thereapeutic help. Special growth charts are available of growth in Noonam Syndrome and these may be helpful in giving an estimated final height for a child with Noonan Syndrome. Growth hormone treatment is under clinical study at the present time. Although it certainly improves short-term growth rate, it is not yet possible to say whether GH treatment will affect final height. However, initial evidence has suggested that this treatment is not associated with any deterioration in heart function, despite the commonly occurring heart defects.
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