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ABBREVIATION. SDS, standard deviation score. Turner syndrome is the result of total or partial monosomy of the X-chromosome (45,X; mosaic 45,X/46,XX; and other variants). (1,2) The condition is characterized primarily [...], Objective. To evaluate differences in phenotype and other clinical features between patients who have Turner syndrome diagnosed incidentally (on the basis of a prenatal karyotype performed for reasons unrelated to suspicion of Turner syndrome, eg, advanced maternal age) or traditionally (on the basis of either a prenatal karyotype performed for abnormal ultrasound findings or a postnatal karyotype performed for clinical findings suggesting Turner syndrome). Methods. Analysis was performed on baseline data from 88 girls, aged 9 months to 4 years, who were randomized into a multicenter growth hormone intervention trial. Baseline information included a detailed medical history (especially of cardiac and renal anomalies), examination for presence of phenotypic features characteristic of Turner syndrome, length or height (depending on age) expressed as a standard deviation score, and weight standard deviation score. Patients were classified to either the 'incidental' (N = 16) or the 'traditional' (N = 72) diagnosis group as described above. Results. The incidental group had significantly fewer total phenotypic features of Turner syndrome than the traditional group (3.6 ± 2.9 vs 6.7 ± 2.9). When sub-grouped by karyotype, the proportion of patients who manifested phenotypic features was greatest in patients with a 45,X nonmosaic karyotype, lowest in the patients with 45,X/46,XX mosaicism, and intermediate in those with 'other' karyotypes. Fewer congenital cardiac defects were observed in the incidental group (31%) compared with the traditional group (64%), but there was no difference between the groups in the prevalence of renal defects. Karyotype distribution differed significantly between the traditional and incidental groups: 74% versus 19% had the nonmosaic 45,X karyotype in the traditional group and 7% versus 56% had the mosaic 45,X/46,XX karyotype. Conclusions. Patients whose Turner syndrome was diagnosed incidentally had significantly fewer phenotypic features and cardiac defects, as well as a greater proportion of mosaic karyotypes, compared with patients whose Turner syndrome was diagnosed clinically. These results support the theory that significant ascertainment bias exists in our understanding Turner syndrome, with important implications for prenatal counseling. Pediatrics 2004;114:640-644; Turner syndrome, ascertainment bias, prenatal diagnosis, prenatal counseling, karyotype, phenotype, amniocentesis, cardiac anomalies.

Abstract: Turner syndrome is a chromosomal disorder due to an absent or abnormal X chromosome. The two most typical features are short stature and gonadal dysgenesis. There is a wide range of other phenotypic features, many of which are thought secondary to lymphedema during embryogenesis. Reviewed are common sequelae of lymphatic obstruction, as well as common tooth and skin findings. [Copyright &y& Elsevier]

The goals of this study were to test the hypothesis that girls with Turner syndrome (TS) experience growth failure early in life and to establish model-based normative growth charts for 0- to 8-year-old American girls with TS. Full-term girls with TS who had 5 or more measurements of height obtained during their first 10 years of life prior to initiation of growth hormone, estrogen and/or androgen therapy were eligible for this study. A nonlinear mixed-effects model comprising the first two components of the infancy-childhood-puberty (ICP) model of growth was fitted to the longitudinal height measurements and compared with those of healthy American girls. Height measurements (n = 1,146) from 112 girls with TS (45,X: 57.1%; 45,X/46,XX: 12.5%; 46,X, iso(X): 4.5%, and other: 25.9%) were analyzed. Mean height SDS fell from –0.68 at birth to –1.60 at 1 year, –1.80 at 2 years and –1.95 at 3 years. When compared to controls (676 girls, 4,537 measurements), girls with TS grew more slowly due to three principal factors: a slow growth rate of the infancy component, a slow growth rate at the onset of the childhood component, and delayed onset of the childhood component. Traditional concepts of growth failure in TS should be revised. Physicians should consider the diagnosis of TS in any girl with unexplained failure to thrive or short stature, even in the first 3 years of life.Copyright © 2002 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

A 2-week-old infant presented with bilateral rib fractures, hypercalcemia, and subperiosteal bone erosions. Parathyroid hormone levels were elevated and urine calcium low. Her parent's laboratory test results were normal. Gene sequencing revealed a new mutation of the calcium-sensing receptor gene, causing severe neonatal hyperparathyroidism, a variant of hypocalciuric hypercalcemia. This is a rare cause of neonatal hyperparathyroidism and nonabusive fractures.

Marshall-Smith syndrome is characterized by accelerated osseous maturation, craniofacial anomalies, failure to thrive, psychomotor delay, hypotonia, pulmonary dysfunction, and limited life expectancy. We describe a 7-year-old girl who, in addition to meeting these criteria for Marshall-Smith syndrome, had multiple fractures and skeletal anomalies. The purpose of this report is to draw attention to Marshall-Smith syndrome as one of the skeletal dysplasias characterized by osseous fragility., (Copyright 2003 Wiley-Liss, Inc.)