Pseudoisodicentric Xp chromosome [46,X,psu idic(X)(q21.1)] and its effect on growth and pubertal development.

BACKGROUND: Most isodicentric (Xp) and (Xq) chromosomes occur as a mosaic with a 45,X cell line. Patients with a nonmosaic 46,X,idic(Xq) are rare. CASES: The first girl was referred at 13 years with a short stature and pubertal delay (M1, P2, A1). Her height was 141.6 cm (-3.1 SDS). Ovarian failure was present. The second girl was referred because of her short stature at 12.5 years. Her height was 142.2 cm (-2.4 SDS). She had spontaneous puberty (M3, P1, A1). RESULTS: In both girls, conventional karyotyping of lymphocytes revealed an aberrant X chromosome consisting of twice the short arm and a small part of the long arm of the X chromosome [nonmosaic 46,X,psu idic(X)(q21.1)]. FISH analysis of the aberrant X chromosome showed the presence of two centromeres, two copies of the XIST gene and two copies of the SHOX gene. CONCLUSIONS: The presence of two XIST genes on the isodicentric X chromosome with Xq deletion indicates the inactivation of this chromosome. This inactivation also concerned the pseudoautosomal regions which caused haploinsufficiency of the SHOX genes. The girls were treated with growth hormones. The critical region (Xq23 to Xq28) for the ovarian function was deleted in both patients, but the gonadal function was variable. .

A variable degree of intrauterine and postnatal growth retardation in a family with a missense mutation in the insulin-like growth factor I receptor.

CONTEXT: The type 1 IGF-I receptor (IGF1R) mediates the biological functions of IGF-I. Binding of IGF-I to the IGF1R results in autophosphorylation of the intracellular beta-subunit and activation of intracellular signaling. OBJECTIVE: The objective of this study was to evaluate the functional characteristics of a novel IGF1R mutation and describe the phenotypic features of two patients with this mutation. DESIGN: The study was performed in a university hospital. PATIENTS: We describe a 35-yr-old female with mild intrauterine growth failure, progressive postnatal growth retardation, severe failure to thrive, and microcephaly. Her daughter was born with severe intrauterine growth retardation and also showed postnatal failure to thrive and microcephaly. RESULTS: We found a heterozygous G3148-->A nucleotide substitution in the IGF1R gene, changing a negatively charged glutamic acid at position 1050 into a positively charged lysine residue (E1050K). E1050 is a conserved residue in the intracellular kinase domain. Dermal fibroblasts of the mother showed normal binding of iodinated IGF-I, but autophosphorylation and activation of downstream signaling cascades upon challenging with IGF-I was markedly reduced. Consequently, the maximal [(3)H]thymidine incorporation upon challenge with a dose range of IGF-I was reduced compared with a panel of control cells (3.65 +/- 1.79-fold vs. 6.75 +/- 4.7-fold stimulation; P < 0.01). These data suggest that the mutation results in the inactivation of one copy of the IGF1R gene. CONCLUSIONS: These two patients support the key role for IGF-I in intrauterine and postnatal growth. The different phenotypes of these and earlier described patients may be associated with variability in IGF-I signaling. The degree of intrauterine growth retardation may be partially determined by the presence or absence of maternal IGF-I resistance.

Longitudinal analysis of growth and puberty in 21-hydroxylase deficiency patients.

AIMS: To evaluate growth from diagnosis until final height (FH) in 21-hydroxylase deficiency patients. METHODS: A retrospective longitudinal study was performed. Only patients treated with hydrocortisone and fludrocortisone (in case of salt wasting) were evaluated. This resulted in a sample of 34 (21 male, 13 female) salt wasting patients (SW) and 26 (13 male, 13 female) non-salt wasting patients (NSW). Auxological data were compared to recent Dutch reference values. RESULTS: In the first three months of life, the mean length SDS decreased to -1.50, probably because of the high average glucocorticoid dose (40 mg/m2/day). FH corrected for target height (FH(corr)TH) was -1.25 and -1.27 SDS in females and males, respectively. Patients treated with salt supplements during the first year, had a better FH(corr)TH (-0.83 SDS). In NSW patients, FH(corr)TH was -0.96 and -1.51 SDS in females and males, respectively. In SW and NSW, age at onset of puberty was within normal limits, but bone age was advanced. Mean pubertal height gain was reduced in males. Body mass index was only increased in NSW females. CONCLUSION: In SW, loss of final height potential might be a result of glucocorticoid excess in the first three months and sodium depletion during infancy. In NSW, loss of FH potential was caused by the delay in diagnosis. In SW and NSW, the advanced bone age at onset of puberty (undertreatment in prebertal years) resulted in loss of height gain during puberty. The effect of intensive sodium chloride support in early infancy should be examined prospectively. Neonatal screening is required if the height prognosis in NSW patients is to be improved.

Newborn screening for congenital adrenal hyperplasia in the Netherlands.

OBJECTIVE: To evaluate whether congenital adrenal hyperplasia (CAH) patients can be detected by newborn screening before the occurrence of life-threatening salt wasting and whether the prevalence, specificity, and sensitivity are adequate enough for a routine screening procedure. DESIGN: From 1998, a 2-year regional pilot screening for CAH was performed. In 1998, cutoff levels for 17OHP were primarily based on birth weight, and in 1999 on gestational age. In addition, nationwide, all newly diagnosed patients with CAH were reported to the Dutch Pediatric Surveillance Unit to compare screened CAH patients with CAH patients in the area without screening. RESULTS: In 2 years, 176 684 newborns were screened and 15 CAH patients (7 males/8 females) were detected. Therapy was started at the median age of 7 days. In the area without screening, 223 307 infants were born and 19 CAH patients (10 males/9 females) were reported to the Dutch Pediatric Surveillance Unit. Therapy was started at the median age of 14 days. The mean (standard deviation) serum sodium concentration was 134.5 (3.4) mmol/L in the area of screening versus 124.5 (10.8) mmol/L in the area without screening. The overall prevalence was 1:11 764. In 1998 and 1999, the specificity was 99.76% and 99.97%, respectively. The positive predictive value was 4.5% and 16%, respectively. To date, no false-negative cases have been detected. CONCLUSION: Severe salt wasting can be prevented by neonatal screening. The prevalence, specificity, and sensitivity allowed addition of screening for CAH to the routinely performed national neonatal screening program.

Effects of total-body irradiation on growth, thyroid and pituitary gland in rhesus monkeys.

PURPOSE: To investigate the effect of total-body irradiation (TBI) on growth, thyroid and pituitary gland in primates. METHODS AND MATERIALS: Thirty-seven rhesus monkeys (mean age 3.1+/-0.6 years) received either a low-dose (4-6 Gy) TBI (n = 26) or high-dose (7-12 Gy) TBI (n = 11) and were sacrificed together with 8 age-matched controls after a post-irradiation interval of 5.9+/-1.5 years. Anthropometric data were collected: thyroid and pituitary glands were examined; serum levels of thyroid stimulating hormone (TSH), free thyroxin (FT4), insulin-like growth factor-I (IGF-I) and its binding protein-3 (IGFBP-3) were measured. RESULTS: Decrease in final height due to irradiation could not be demonstrated. There was a dose-dependent decrease in body weight, ponderal index, skinfold thickness and thyroid weight. The latter was not accompanied by elevation of TSH or decrease in FT4. Structural changes in the thyroid gland were found in 50% of the irradiated animals. Levels of IGF-I and IGFBP-3 did not differ between the dose groups, but the high-dose group had a lower IGF-1/IGFBP-3 ratio. CONCLUSION: Total body irradiation had a negative effect on body fat. There was no evidence of (compensated) hypothyroidism, but dose-dependent decrease in thyroid weight and changes in follicular structure suggest some effect of TBI on the thyroid gland. The decreased IGF-I/IGFBP-3 ratio in the high-dose group can indicate that the somatotrophic axis was mildly affected by TBI. These results show that TBI can have an effect on the physical build and thyroid gland of primates even in the absence of cytostatic agents or immunosuppressive drugs.

Comparison of immunoaffinity columns with Florisil/C18 columns for the determination of aflatoxins in animal feed and maize.

A study of the performance of the EC method and an Immunoaffinity method for aflatoxins B1,B2,G1 and G2 in animal feed and maize was performed. The extraction and HPLC analysis of both procedures were comparable,hence a direct comparison of the performance of the alternative clean- up columns was made. Throughout the study the results were similar for both methods,however,the main advantage of the Immunoaffinity method was fewer manipulations were required. Therefore the method was easier to use,less solvent was required and greater sample throughput (approximately 2 fold) was obtained.

Evaluation of young women with congenital adrenal hyperplasia: a pilot study.

To evaluate the outcome of medical and surgical treatment of 10 young women with congenital adrenal hyperplasia (CAH), final height, weight, body proportions and body hair growth as well as aspect and functionality of the external genitalia were assessed. The final height was below-2 SD of the target height in 55%, though the body proportions were in the normal range. Only 3 patients were menstruating regularly. Scores for 'hormonal' body hair growth were in a higher range. Gynaecological examination revealed that in 5 out of 9 patients, the genitalia were functionally acceptable. This pilot study stresses that from birth into adulthood of female patients with CAH there is a need for a combined therapeutic approach by a paediatric endocrinologist, a surgeon and a psychologist. This will improve the physical and psychosocial well-being of these patients.

Formation of mutagenic N-nitroso compounds in vegetable extracts upon nitrite treatment: a comparison with the glucosinolate content.

More than 30 vegetables were screened for their potential to form biologically active N-nitroso compounds upon treatment with nitrite under acidic conditions. The total N-nitroso content was determined in the nitrite-treated and untreated extracts of the vegetables according to a modified method of Walters et al. (Analyst, Lond. 1978, 103, 1127). All treated extracts contained N-nitroso compounds at levels ranging from 23 to 789 nmol/25 mg dry matter. In the same samples the mutagenic activity was determined using the Salmonella typhimurium assay. About half of the vegetables were found to be mutagenic upon nitrite treatment. (Nitrite-treated extracts were considered to be mutagenic if the number of induced revertants was at least twice as high as that induced by the corresponding untreated extract). The content of different glucosinolates in the dry matter of the vegetables was also determined. Glucosinolates could be detected only in cruciferous vegetables, at levels ranging from 1.8 to 26.0 mumol/g dry matter. Although the nitrite-treated extracts of brassica species contained more N-nitroso compounds and induced more revertants than did other vegetables, there was no significant correlation between these parameters. However, the amounts of N-nitroso compounds formed upon nitrite treatment (expressed per fresh weight) did correlate significantly (P less than 0.01) with the amounts of glucosinolates (r = 0.95). When the glucosinolates were divided into aryl/alkyl- and indolyl-glucosinolates, the significant correlation was maintained for both subgroups (r = 0.93 and 0.95, respectively). From this it can be concluded that glucosinolates are probably involved in the formation of N-nitroso compounds in certain nitrite-treated vegetables.