Ronald Youlton

Prevalence of components of the metabolic syndrome according to birthweight among overweight and obese children and adolescents

Abstract Background/objectives: Extremes of birthweight (BW) have been associated with increased rates of metabolic risks. The objective was to study the prevalence of metabolic risks markers among obese and overweight (OW) subjects according to BW. Subjects/methods: A cross-sectional study was performed in a cohort of 1002 patients (2–18 years, 40.6% male) evaluated for OW or obese subjects in two private clinics. Anthropometrics, fasting lipids, glycemia, and insulin were obtained. Results: Of the subjects, 76.1% were born appropriate for gestational age (AGA), 10.9% small for gestational age (SGA), and 13% large for gestational age (LGA). Children born LGA presented a more severe degree of obesity compared with those born AGA and SGA (p<0.0001). No differences in glycemia, insulin, and lipid levels were detected among the groups. Abnormal glucose was found in 37 subjects: one with type 2 diabetes mellitus (from the previously glucose-intolerant subjects), 10 with glucose intolerance, and 27 with impaired fasting glucose. According to Boney criteria, 6.6% of the patients (6–18 years old) exhibited metabolic syndrome (MS) (69.4% AGA, 12.9% SGA, and 17.7% LGA). Conclusions: Being born LGA represents a higher risk of severe obesity. At this age, the most frequent component of MS was an abnormal lipid profile with low high-density lipoprotein and high triglycerides. Finally, the most frequent finding associated with abnormalities of glucose tolerance was a family history of diabetes. Thus, BW, lipid profile, and family history are mandatory when these patients are evaluated.

Ghrelin plasma levels in patients with idiopathic short stature.

Background: Novel molecular insights have suggested that ghrelin may be involved in the pathogenesis of some forms of short stature. Recently, growth hormone secretagogue receptor (GHSR) mutations that segregate with short stature have been reported. Aim: To study plasma ghrelin levels in prepubertal patients with idiopathic short stature (ISS). Methods: Fasting total plasma ghrelin levels (radioimmunoassay) in 41 prepubertal patients with ISS (18 females, age 7.9 ± 0.5 years) compared with 42 age- and sex-matched controls (27 females, age 8.0 ± 0.3 years) with normal height. In a subset of 28 patients, the ghrelin receptor was sequenced. Results: ISS patients exhibited a higher level of ghrelin (1,458 ± 137 vs. 935 ± 55 pg/ml, p < 0.01) and similar IGF-I levels (–0.66 ± 1.29 vs. –0.32 ± 0.78 SDS) compared to controls. Ten patients with ISS had ghrelin levels greater than +2 SDS compared to controls. These patients did not differ in height, BMI or IGF-I SDS compared to ISS patients with ghrelin levels within the normal range. Molecular analysis of GHSR did not show any mutations, but showed some polymorphisms. Conclusion: These results suggest that in ISS patients, short stature does not appear to be frequently caused by abnormalities in ghrelin signaling.

Síndrome de Turner: Crecimiento y descripción clínica en 83 niñas chilenas

Background: Short stature is the main feature of patients with Turners syndrome. There is limited information regarding the spontaneous growth of these patients in Chile. Aim: To develop a specific growth chart for Chilean patients with Turners syndrome. Material and methods: We retrospectively analyzed 668 height measurements from 85 Chilean girls, born after 1968, with 45XO karyotype (minimum 15%), and without an Y chromosome fragment. Patients with hormonal therapy, such as growth hormone or estrogen, except thyroid hormone replacement, were excluded. Results: The karyotypes were 60% 45XO, 25% 45XO, 46XX, and 15% other complex mosaics. The birth length was 46.8 ± 2.1 cm. The final height of our patients was 138,20 ± 7,0 cm. Conclusions: The final height achieved by our patients, is similar to Argentinian and Japanese patients, but is below the mean stature reported for Scandinavian and Northamerican patients who achieve a mean adult height of approximately 147 and 142 cm respectively. The birth length is also lower than that reported in those studies (Rev Med Chile 2002; 130: 977-84).

Pure XX gonadal dysgenesis in identical twins

Pure gonadal dysgenesis has been described in several sibships. We report a pair of monozygous twins and their younger sister with secondary amenorrhea. They had no associated congenital anomalies. Plasma FSH levels were elevated and the ovarian biopsies showed absence of follicular structures. Their karyotypes were 46XX, further supporting the concept that this form of familial gonadal dysgenesis is an autosomal recessive defect.

Accuracy of the haemoglobin alkaline denaturation test for detecting maternal blood contamination of fetal blood samples for prenatal karyotyping

The haemoglobin alkaline denaturation test was routinely performed in 183 fetal blood samples obtained by cordocentesis for prenatal karyotyping by adding 0.1 ml of the blood into a glass test tube containing 5 ml of water and 0.3 ml of 10 per cent KOH as the alkali reagent. The mixture was agitated gently and read at 2 minutes, at which time it was interpreted as a pure fetal blood sample or contaminated with maternal blood according to the change in colour. In order to determine the accuracy of this test to detect maternal blood contamination, the results were compared with the number of fetal and maternal cells detected by standard cytogenetic techniques in those blood samples obtained from male fetuses (n=97). Among these samples, the haemoglobin alkaline denaturation test gave an adult haemoglobin reaction in two cases (2.1 per cent); both samples showed different degrees of maternal 46,XX cells in the metaphases examined (29 of 30 cells in one case and 2 of 31 cells in the other). Conversely, of the 95 samples which gave a fetal haemoglobin reaction, the cytogenetic analysis did not reveal any maternal cells in the metaphases analysed (median 30 cells, range 20–65). We concluded that the haemoglobin alkaline denaturation test is an accurate method for excluding clinically significant maternal blood contamination of fetal blood samples obtained for prenatal karyotyping. This simple, inexpensive technique provides immediate information and, therefore, can be safely incorporated as a bedside test for analysis during fetal blood sampling procedures. Copyright

Pubarquia precoz: Experience in 173 cases

Background: Precocious pubarche (PP), defined as the development of sexual pubic hair before 8 years of age in females and before 9 years in males, is usually a benign condition but it can also be the first sign of an underlying disease. Aim: To analyze the etiology and perform a short term follow up in a cohort ofpatients with PP. Material and methods: A group of 173patients (158 females) consulted for PP with a mean age of 7.4+0.1 years. These patients were followed between 15 to 60 months. Anthropometric measurements, bone age, serum levels of total testosterone, 17 OH progesterone (17 OHP) and dehydroepiandrosterone sulphate (DHEAS) were evaluated. Results: Mean birth weight and length was 3024.1+50.5 g and 48.5+0.3 cm, respectively. Ten percent of children were small for gestational age at birth. Bone age was accelerated by 1.1+0.01 years. One hundred and twelve patients were classified as having idiopathic PP (64.7%; 105 females), 29 as central precocious puberty (16.8%; only females), 16 as exaggerated adrenarche (EA 9.2%; 13 females) and 16 as non classical adrenal hyperplasia (9.2%; 11 females). Conclusions: PP represents a common and usually benign sign. However, 26% of cases had a pathologic underlying condition. Therefore, all children with PP should be evaluated by a pediatric endocrinologist. Low birth weight was not frequent in this cohort and these patients did not show EA .

Pure XX Gonadal Dysgenesis in Identical Twins

Pure gonadal dysgenesis has been described in several sibships. We report a pair of monozygous twins and their younger sister with secondary amenorrhea. They had no associated congenital anomalies. Plasma FSH levels were elevated and the ovarian biopsies showed absence of follicular structures. Their karyotypes were 46XX, further supporting the concept that his form of familial gonadal dysgenesis is an autosomal recessive defect.