Wetenschappelijk vervolgonderzoek Turner Oxandrolon Studie.

Background:
Turner syndrome is the result of complete or partial absence of one X-chromosome. Besides short stature and gonadal dysgenesis, Turner syndrome is associated with a wide range of abnormalities affecting nearly every organ system. In 1991 the Dutch multicentre Turner Oxandrolone Study (TOS) started: a randomized double-blind placebo controlled study on the effect of the androgen oxandrolone (Ox) in combination with authentic biosynthetic human growth hormone and low-dose estrogens on growth and metabolic parameters in girls with Turner syndrome (CEOM-nr 9202-0029). In TOS, the girls were followed until a mean of 1.5 years after cessation of growth hormone and Ox/placebo. Preliminary analysis suggests that Ox enhances growth at cost of mild virilization and deceleration of breast development, especially in the high-dose group. The beneficial and possible adverse effects of Ox potentially carry on into adulthood, i.e. far beyond the scope of the original pediatric study. The present study represents a long term follow-up of TOS. The girls who participated in the original TOS have now reached an adult age.

Aim and hypothesis:
The aim of the study is to assess the long-term effects (at adult age) of the TOS study medication (growth hormone and estrogen with or without Ox), with specific attention to adult height and body proportions, body composition, virilization, metabolic cardiovascular risk profile, neuropsychological function and quality of life. Our hypothesis, is that permanent beneficial effects of auxiliary treatment with Ox outweigh short-lived adverse effects.

Study design:
This is an observational study and represents the long-term follow-up of a multicentre double-blind placebo controlled trial.

Study population:
The participants of the original TOS trial (N=133) will be recruited.

Main study parameters:
Height, body proportions, body composition, symptoms and signs of virilization, glucose tolerance, lipid profile, cardiac conduction abnormalities, liver and thyroid function, (neuro)psychological function and quality of life. The effects of Ox are analyzed to a background of genotypic variation of the sex chromosomes and the growth hormone receptor.

Methods, procedures, burden and risk:
Participating subjects are investigated during a single, whole-day visit to the RUNMC which comprises of standardized history taking and physical examination including standardized photographs, sampling of blood, urine, hair and buccal mucosa, (neuro)psychological investigations, voice frequency analysis and audiometry, bone mineral density and body composition measurement and electrocardiography. Laboratory evaluation includes assessment of lipid profile, androgen hormone status, kidney-, liver- and thyroid function, and genotyping (tissue-specific sex-chromosomal karyotyping, X-chromosomal imprinting and growth hormone receptor polymorphism). The risks associated with these investigations for the participants are minimal.

In 1991 the Dutch multicentre Turner Oxandrolone Study (TOS) started: a randomized double-blind placebo controlled study on the effect of the androgen oxandrolone (Ox) in combination with authentic biosynthetic human growth hormone and low-dose estrogens on growth and metabolic parameters in girls with Turner syndrome. The aim of this follow up study is to assess the long-term effects (at adult age) of the TOS study medication (growth hormone and estrogen with or without Ox), with specific attention to adult height and body proportions, body composition, virilization, metabolic cardiovascular risk profile, neuropsychological function and quality of life. Our hypothesis, is that permanent beneficial effects of auxiliary treatment with Ox outweigh short-lived adverse effects.

One day visit to assess longterm effect of Oxandrolone.

Participating subjects are investigated during a single, whole-day visit to the RUNMC which comprises of standardized history taking and physical examination including standardized photographs, sampling of blood, urine, hair and buccal mucosa, (neuro)psychological investigations, voice frequency analysis and audiometry, bone mineral density and body composition measurement and electrocardiography. Laboratory evaluation includes assessment of lipid profile, androgen hormone status, kidney-, liver- and thyroid function, and genotyping (tissue-specific sex-chromosomal karyotyping, X-chromosomal imprinting and growth hormone receptor polymorphism).