Effect of puberty on the relationship between bone markers of turnover and bone mineral density in Turner's syndrome.

It has been suggested that the appropriate timing of puberty is necessary for normal bone mineral acquisition which may not be achieved amongst patients with Turner's syndrome (TS). The aim of this study was to assess bone mineral density (BMD) and bone turnover in 34 patients with TS (age range 2.2-39.0 years). The areal BMD (aBMD) was determined by dual-energy X-ray absorptiometry, and the volumetric BMD was calculated. Blood and second voided urine samples were taken the morning after an overnight fast for evaluation of the biochemical markers of bone turnover: bone-specific alkaline phosphatase (BAP) and N-telopeptides of type I collagen (NTX), respectively. Both were determined by enzyme-linked immunosorbent assay. The patients were divided into three groups: group 1 (n = 13; prepubertal; age range 2.2-19.0 years), group 2 (n = 10; teenagers; age range 12.4-19.0 years), and group 3 (n = 11; adults; chronological age >20 years). They were also grouped by breast development according to Tanner stage into B1 (n = 12), B2-3 (n = 9), and B4-5 (n = 13). The aBMD was significantly lower in group 1 and was higher at Tanner stages 4 and 5 as compared with patients at Tanner stage 1. The bone turnover markers were significantly higher in group 1 (NTX: p = 0.002; BAP: p = 0.0005) and declined, as puberty progressed. A negative correlation was observed between aBMD and biochemical bone markers at the lumbar spine (NTX: r = -0.54, p = 0.05; BAP: r = -0.44, p = 0.01) and in the whole body (NTX: r = -0.60, p = 0.0008; BAP: r = -0.19, p = 0.002). We conclude that the negative relationships between aBMD and biochemical markers suggest a high bone turnover, mainly in prepubertal patients and that the results observed in relation to aBMD and puberty are imputed to the delayed puberty which occurs amongst TS patients.

Association of Turner's syndrome and hypopituitarism: a patient report.

Turner's syndrome (TS) is associated with a wide spectrum of clinical features, such as short stature and gonadal dysgenesis. While it is a common chromosomal abnormality, the association of Turner's syndrome and hypopituitarism is an uncommon finding. We describe here a girl with concomitant pituitary insufficiency and gonadal dysgenesis. When she was 7 years old, her mother reported that she suffered from frontal headache, asthenia and delayed growth. Basal laboratory thyroid evaluation suggested hypothyroidism, with no evidence of autoimmune disease association. She began taking L-thyroxine. At age 11 years, short stature and complaints of frontal headache still persisted. She was still prepubertal and her bone age was delayed by 2.2 years. Her karyotype was compatible with 45,X/46,XX (100 cells analyzed by FISH) and a CT scan showed empty sella. At 12 years of age, an anterior pituitary stimulation test with insulin, gonadotropin-releasing hormone (GnRH) and thyrotropin-releasing hormone (TRH) showed gonadotropin, thyrotropin (TSH) and growth hormone (GH) deficiency. Replacement therapy with GH was begun and she grew 12 cm during the first year of treatment. This report illustrates that, despite the high incidence of sinusitis, short stature and primary hypothyroidism in TS, we should consider the presence of hypopituitarism when the patient presents low levels of TSH with negative thyroid antibodies and inappropriately low levels of gonadotropins for patients with gonadal dysgenesis.