[Turner syndrome: spontaneous growth of stature, weight increase and accelerated bone maturation]

Growth Hormone Treatment to Final Height in Turner Syndrome: Systematic Review

PURPOSE

Turner syndrome (TS) is the most common sex chromosomal abnormality found in female subjects. It is a result of a partial or complete loss of one of the X chromosomes. Short stature is a hallmark of TS. Attainment of adult height (AH) within the normal range for height within the general female population represents the usual long-term goal of growth hormone (GH) treatment. The aim of this systematic review was to understand the efficacy of GH therapy on AH of patients with TS.

METHODS

The literature review yielded for analysis 9 articles published from 2010 to 2021. Using the data from this literature search, the goal was to answer 5 questions: (1) What is the efficacy of GH on AH of girls with TS?; (2) Is AH influenced by the age at initiation of GH treatment?; (3) What is the optimal dose of GH to improve AH?; (4) Can the timing of either spontaneous or induced puberty influence AH?; and (5) Can the karyotype influence AH in patients with TS?

FINDINGS

GH therapy and adequate dose could enable patients with TS to achieve appropriate AH compared with the possible final height without therapy. The greatest increase in height during GH therapy occurs in the prepubertal years, and if therapy is continued to AH, there is no further increase. Furthermore, karyotype did not show a predictive value on height prognosis and did not affect the outcome of GH administration or the height gain in girls with TS.

IMPLICATIONS

Even if GH therapy is safe, close monitoring is indicated and recommended. Further evidence is needed to understand what other parameters may influence AH in patients undergoing GH therapy.

Early GH Treatment Is Effective and Well Tolerated in Children With Turner Syndrome: NordiNet® IOS and Answer Program

CONTEXT

Despite having normal growth hormone (GH) secretion, individuals with Turner syndrome (TS) have short stature. Treatment with recombinant human GH is recommended for TS girls with short stature.

OBJECTIVE

This work aimed to evaluate the effectiveness and safety of Norditropin (somatropin, Novo Nordisk) with up to 10 years of follow-up in children with TS.

METHODS

Secondary analysis was conducted of Norditropin data from 2 non-interventional studies: NordiNet® IOS (NCT00960128) and the ANSWER program (NCT01009905).

RESULTS

A total of 2377 girls with TS were included in the safety analysis set (SAS), with 1513 in the treatment-naive effectiveness analysis set (EAS). At the start of treatment, 1273 (84%) participants were prepubertal (EAS); mean (SD) age was 8.8 (3.9) years. Mean (SD) dose received at the start of GH treatment was 0.045 (0.011) mg/kg/day (EAS). Mean (SD) baseline insulin-like growth factor-1 (IGF-I) SD score (SDS) was -0.86 (1.52), and mean (SD) duration of GH treatment (SAS) was 3.8 (2.8) years.Height SDS (HSDS) increased throughout follow-up, with near-adult HSDS reached by 264 (17%) participants (mean [SD] -1.99 [0.94]; change from baseline +0.90 [0.85]). During the study, 695 (46%) participants (EAS) entered puberty at a mean (SD) age of 12.7 (1.9) years (whether puberty was spontaneous or induced was unknown). Within the SAS, mean IGF-I SDS (SD) at year 10 was 0.91 (1.69); change from baseline +1.48 (1.70). Serious adverse reactions were reported in 10 participants (epiphysiolysis [n = 3]).

CONCLUSION

GH-treated participants with TS responded well, without new safety concerns. Our real-world data are in agreement with previous studies.

Cell-free DNA screening positive for monosomy X: clinical evaluation and management of suspected maternal or fetal Turner syndrome

Initially provided as an alternative to evaluation of serum analytes and nuchal translucency for the assessment of pregnancies at high risk of trisomy 21, cell-free DNA screening for fetal aneuploidy, also referred to as noninvasive prenatal screening, can now also screen for fetal sex chromosome anomalies such as monosomy X as early as 9 to 10 weeks of gestation. Early identification of Turner syndrome, a sex chromosome anomaly resulting from the complete or partial absence of the second X chromosome, allows medical interventions such as optimizing obstetrical outcomes, hormone replacement therapy, fertility preservation and support, and improved neurocognitive outcomes. However, cell-free DNA screening for sex chromosome anomalies and monosomy X in particular is associated with high false-positive rates and low positive predictive value. A cell-free DNA result positive for monosomy X may represent fetal Turner syndrome, maternal Turner syndrome, or confined placental mosaicism. A positive screen for monosomy X with discordant results of diagnostic fetal karyotype presents unique interpretation and management challenges because of potential implications for previously unrecognized maternal Turner syndrome. The current international consensus clinical practice guidelines for the care of individuals with Turner syndrome throughout the lifespan do not specifically address management of individuals with a cell-free DNA screen positive for monosomy X. This study aimed to provide context and expert-driven recommendations for maternal and/or fetal evaluation and management when cell-free DNA screening is positive for monosomy X. We highlight unique challenges of cell-free DNA screening that is incidentally positive for monosomy X, present recommendations for determining if the result is a true-positive, and discuss when diagnosis of Turner syndrome is applicable to the fetus vs the mother. Whereas we defer the subsequent management of confirmed Turner syndrome to the clinical practice guidelines, we highlight unique considerations for individuals initially identified through cell-free DNA screening.

A Polygenic Risk Score to Predict Future Adult Short Stature Among Children

CONTEXT

Adult height is highly heritable, yet no genetic predictor has demonstrated clinical utility compared to mid-parental height.

OBJECTIVE

To develop a polygenic risk score for adult height and evaluate its clinical utility.

DESIGN

A polygenic risk score was constructed based on meta-analysis of genomewide association studies and evaluated on the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort.

SUBJECTS

Participants included 442 599 genotyped White British individuals in the UK Biobank and 941 genotyped child-parent trios of European ancestry in the ALSPAC cohort.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Standing height was measured using stadiometer; Standing height 2 SDs below the sex-specific population average was considered as short stature.

RESULTS

Combined with sex, a polygenic risk score captured 71.1% of the total variance in adult height in the UK Biobank. In the ALSPAC cohort, the polygenic risk score was able to identify children who developed adulthood short stature with an area under the receiver operating characteristic curve (AUROC) of 0.84, which is close to that of mid-parental height. Combining this polygenic risk score with mid-parental height or only one of the child's parent's height could improve the AUROC to at most 0.90. The polygenic risk score could also substitute mid-parental height in age-specific Khamis-Roche height predictors and achieve an equally strong discriminative power in identifying children with a short stature in adulthood.

CONCLUSIONS

A polygenic risk score could be considered as an alternative or adjunct to mid-parental height to improve screening for children at risk of developing short stature in adulthood in European ancestry populations.

Lack of consensus in the choice of termination of pregnancy for Turner syndrome in France

BACKGROUND

The observed rate of termination of pregnancy (TOP) for Turner syndrome varies worldwide and even within countries. In this vignette study we quantified agreement among ten multidisciplinary prenatal diagnosis centers in Paris.

METHODS

We submitted online three cases of Turner syndrome (increased nuchal translucency, normal ultrasound, aortic coarctation) to fetal medicine experts: one obstetrician, one pediatrician and one geneticist in each of the ten Parisian centers. Each case was presented in the form of a progressive clinical history with conditional links dependent upon responses. The background to each case was provided, along with the medical history of the parents and the counseling they got from medical staff. The experts indicated online whether or not they would accept the parents' request for TOP. We assessed the percentage of agreement for acceptance or refusal of TOP. We also used a multilevel logistic regression model to evaluate differences among obstetrician-gynecologists, pediatricians and cytogeneticists.

RESULTS

Overall agreement among the experts to accept or refuse TOP was, respectively, 25 and 28%. The percentage of disagreement was 47%. The percentage of agreement to accept TOP was 33, 8 and 33% for obstetrician-gynecologists, pediatricians and cytogeneticists, respectively. The respective percentages of agreement to refuse TOP were 19, 47 and 26%.

CONCLUSION

Our results show the lack of consensus with regard to decisions related to termination of pregnancy for Turner Syndrome. This lack of consensus in turn underscores the importance of multidisciplinary management of these pregnancies in specialized fetal medicine centers.

X-chromosome gene dosage as a determinant of impaired pre and postnatal growth and adult height in Turner syndrome

OBJECTIVE

Short stature is a key aspect of the phenotype of patients with Turner syndrome (TS). SHOX haploinsufficiency is responsible for about two-thirds of the height deficit. The aim was to investigate the effect of X-chromosome gene dosage on anthropometric parameters at birth, spontaneous height, and adult height (AH) after growth hormone (GH) treatment.

DESIGN

We conducted a national observational multicenter study.

METHODS

Birth parameter SDS for gestational age, height, and AH before and after GH treatment respectively, and height deficit with respect to target height (SDS) were classified by karyotype subgroup in a cohort of 1501 patients with TS: 45,X (36%), isoXq (19%), 45,X/46,XX (15%), XrX (7%), presence of Y (6%), or other karyotypes (17%).

RESULTS

Birth weight, length (P<0.0001), and head circumference (P<0.001), height and height deficit with respect to target height (SDS) before GH treatment, at a median age of 8.8 (5.3-11.8) years and after adjustment for age and correction for multiple testing (P<0.0001), and AH deficit with respect to target height at a median age of 19.3 (18.0-21.8) years and with additional adjustment for dose and duration of GH treatment (P=0.006), were significantly associated with karyotype subgroup. Growth retardation tended to be more severe in patients with XrX, isoXq, and, to a lesser extent, 45,X karyotypes than in patients with 45,X/46,XX karyotypes or a Y chromosome.

CONCLUSION

These data suggest that haploinsufficiency for an unknown Xp gene increases the risk of fetal and postnatal growth deficit and short AH with respect to target height after GH therapy.

Noonan syndrome and Turner syndrome patients respond similarly to 4 years' growth-hormone therapy: longitudinal analysis of growth-hormone-naïve patients enrolled in the NordiNet® International Outcome Study and the ANSWER Program

Background

Turner syndrome (TS) and Noonan syndrome (NS) are distinct syndromes associated with short stature and other similar phenotypic features. We compared the responses to growth hormone (GH) therapy of TS and NS patients enrolled in the NordiNet® International Outcome Study (IOS) or the American Norditropin Studies: Web-Enabled Research (ANSWER) Program, which collect information on GH therapy in clinical practice.

Methods

Repeated-measures regression analysis was performed on change in height standard deviation score (HSDS) and target-height-corrected HSDS, based on national normal references and treatment-naïve disease-specific references. Models were adjusted for baseline age and HSDS, and average GH dose. The study population was paediatric patients with TS and NS in the NordiNet® IOS and ANSWER Program. Longitudinal growth responses over 4 years were evaluated.

Results

In 30 NS patients (24 males; baseline age 8.39 ± 3.45 years) and 294 TS patients (7.81 ± 3.22 years), 4-year adjusted ΔHSDS were +1.14 ± 0.13 and +1.03 ± 0.04, respectively (national references). Based on untreated, disease-specific references, 4-year adjusted ΔHSDS for NS and TS were +1.48 ± 0.10 and +1.79 ± 0.04. The analyses showed a significant increase in HSDS over time for both NS and TS (P < 0.0001). ΔHSDS in NS was higher with younger baseline age; ΔHSDS in TS was higher for patients with younger baseline age and higher GH dose.

Conclusions

NS and TS patients responded well and similarly over 4 years of GH treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s13633-015-0015-1) contains supplementary material, which is available to authorized users.

Weight deficit at birth and Turner's syndrome

Turner's syndrome (TS) is one of the most frequent diseases accompanied by growth deficiency. Though developmental disorders have been observed in the fetal period, there has been disagreement as to whether short stature is frequent in newborn girls with Turner's syndrome. Hence we attempted to determine the incidence of 'small for gestational age' in TS compared with healthy newborns girls delivered at term above -2 SD (body length and weight) for gestational age. The medical records of 548 girls with TS recruited from Polish university and district hospitals were screened, with 468 of them delivered at term (gestational age > or =38 weeks) being included in this study. Mean weight (+/- SD) at birth was 2963 +/- 444 g, which was below the normal value for gestational age in nearly 90%. The mean birth weight deficiency was 600 g, but exceeded 1000 g in over 10%. When a newborn girl delivered at term has a marked weight deficit, Turner's syndrome should be considered. This is especially so when the girl is a product of a first pregnancy, when routine karyotyping is recommended. The condition may arise from a partial dysfunction of a gene or genes on the X-chromosome involved in the control of fetal growth.

Le syndrome de Turner☆☆Cet article est publié en partenariat avec Orphanet et disponible sur le site www.orpha.net. © 2007 Orphanet. Publié par Elsevier Masson SAS. Tous droits réservés

Turner syndrome occurs in 1:5000 live births (1:2,500 females) and is caused not only by X-chromosome monosomy, but also in a large degree, by the presence of a mosaicism (45,X) and/or an abnormal X or Y chromosome (deletion, isochromosome X, dicentric chromosome). Clinical features are heterogeneous and typical physical anomalies are often mild or absent. In all cases, patients are short but final height has been improved by growth hormone therapy. Ovarian failure, with variable onset depending on the chromosomal anomalies, is frequent. Others visceral diseases (bone anomalies, lymphedema, deafness, and cardiovascular, thyroid, gastrointestinal diseases) are less common and need a screening at diagnosis, then a survey during adolescence and adulthood. During gestation, typical forms can be diagnosed by ultrasound examination, but mild forms are discovered incidentally during amniocentesis for unrelated reasons (advanced maternal age) and prenatal advice is difficult. The quality of life and social life is better when puberty is not induced too late, and in absence of cardiac disease or deafness. Deafness can lead to learning difficulties and, during adulthood, sterility can have a negative effect on quality of life. The prognosis depends on heart diseases, obesity, arterial hypertension and osteoporosis. Therefore, a long-term follow-up is necessary.

Apolipoprotein E affects serial changes in total and low-density lipoprotein cholesterol in adolescent girls: Project HeartBeat!

Apolipoprotein E (apo E) polymorphism is a genetic determinant of lipid and lipoprotein levels and the risk for coronary heart disease. The extent to which serial patterns of change in total cholesterol and low-density lipoprotein cholesterol (LDL-C) concentrations varied by apo E genotype was therefore investigated in 247 Caucasian girls aged 8 to 14 at baseline who were participating in Project HeartBeat!, a mixed longitudinal study of cardiovascular disease (CVD) risk factor development in children. Plasma lipid concentrations were determined for each participant three times per year (every 4 months) for up to 4 years from October 1991 through August 1995. Mean total cholesterol values for individuals with epsilon2/3, epsilon3/3, and epsilon3/4 genotypes were 141.7, 161.6, and 165.9 mg/dL, respectively (P < .001). Corresponding LDL-C values for individuals with epsilon2/3, epsilon3/3, and epsilon3/4 genotypes were 74.6, 94.8, and 98.7 mg/dL, respectively (P < .001). The results of longitudinal modeling indicated that age trajectories for total cholesterol and LDL-C varied significantly by apo E genotype. Individuals with epsilon3/3 and epsilon3/4 genotypes exhibited similar patterns of change in total cholesterol and LDL-C from ages 8 to 18, while individuals with the epsilon2/3 genotype demonstrated a significantly different pattern of change (age2 x genotype interaction, P < .05). For example, individuals with the epsilon2/3 genotype showed a slight increase in total cholesterol from approximately 141 to 146 mg/dL from ages 8 to 10; total cholesterol then decreased monotonically from ages 10 to 18 from 146 to 115 mg/dL. The apo E effect on total cholesterol and LDL-C and their change during adolescence is strong and may be modified by factors affecting growth, maturation, and reproductive function.

Phenotypic and genotypic variability in monozygotic triplets with Turner syndrome

Turner syndrome (TS) is a common disorder (1/2500 and 1/5000 female births) which is diagnosed at birth in approximately 20% of patients and during childhood (usually due to growth retardation) or later, (due to lack of pubertal development) for the remaining patients. Here we present a cytogenetic and molecular analysis of three monozygotic sisters. The diagnosis of TS was done for one of them (patient 1) who presented with a typical Turner phenotype. A first karyotype was established as normal and a second karyotype (carried out on 200 cells) revealed a 45,X/46,XX mosaicism with 6% of cells with a 45,X karyotype. Lymphocyte karyotype analysis showed the same mosaicism pattern for the two other sisters, one of them exhibiting only a mild (patient 2) and the other no clinical features of Turner syndrome (patient 3). Karyotype analysis was this time conducted on fibroblasts and showed that the 45,X/46,XX mosaicism pattern correlated with the clinical phenotype with 99, 43 and 3% of 45,X cells in patients 1, 2, and 3, respectively. These data suggest that different tissues other than lymphocytes should be subjected to a karyotype analysis when the observed genotype does not correlate with the clinical phenotype.

Assessment of Turner's syndrome by molecular analysis of the X chromosome in growth-retarded girls

Turner's syndrome (TS) is a common disorder (1/2500 to 1/5000 female births) which is diagnosed at birth in approximately 20% of patients and during childhood or at puberty for the rest. Growth retardation is the most frequent clinical feature of TS, so we systematically searched for TS in female patients referred to our center because of short stature. Three hundred seventy-five female patients, 1 month to 18 yr old (mean +/- SD = 9(7/12) +/- 3(9/12), with growth retardation (less than -2 SD) and/or decreased height velocity were included in the study. Mean growth retardation was -2.57 SD +/- 0.79 (range: -1 to -7). Thirty-two percent of the patients had reached puberty. GH provocative tests were performed in 329 patients (87.7%), and 36 of these patients (11%) had impaired GH secretion (5 complete and 31 partial GH deficiency). TS was evaluated by Southern blot analysis of leukocyte DNA using a multiallelic polymorphic X chromosome marker (88% heterozygosity rate). Y chromosome PCR analysis was carried out if a pattern indicative of TS was obtained. Leukocyte DNA analysis produced an abnormal restriction pattern for 20 of the 375 cases (5.3%). There was a single hybridizing band in 13 cases, an allelic disproportion indicative of mosaicism in 6 cases, and 3 hybridizing bands in 1 case. One patient tested positive in the Y chromosome PCR analysis. Cytogenetic analysis showed 47 XXX trisomy in the patient with a 3-hybridizing-band pattern and confirmed the diagnosis of TS for 17 of the 19 suspected cases: 45 X: n = 7; 45 X/46 Xi(Xq): n = 4; 45 X/46 XX: n = 2; 46 Xi(Xq): n = 1; 45 X/46 Xr(X): n = 1; 45 X/46 XX/47 XXX: n = 1; 45 X/46 XY: n = 1. Cytogenetic analysis was normal (46 XX) for the 2 other patients. The TS phenotype is variable: dysmorphism is often missing or mild (particularly in cases of mosaicism), but growth is reduced in virtually all patients. Screening of 375 growth-retarded girls identified 18 cases of TS, of which 17 were diagnosed by molecular analysis. This incidence (4.8%) was significantly higher than the expected incidence in this population (0.8-1.6%: P < 0.001).

Near normalization of final height with adapted doses of growth hormone in Turner's syndrome

An adapted GH dose regimen was evaluated in 14 untreated patients with Turner's syndrome. The initial GH dose (0.7 U/kg.BW) was increased by 0.7 U/kg.BW, up to a maximum of 2.1 U/kg.BW, when growth velocity (GV) declined to less than 200% of the pretreatment level. These patients were compared to a group of 17 patients with similar initial characteristics, who received a fixed dose of 0.9 U/kg.BW GH. Tolerance to both GH regimens was excellent. The adapted GH doses only partially prevented the waning effect observed with conventional doses of GH, and the initial goal of doubling GV was only achieved in 42% of the 112 patient-semesters. Doubling the GH dose from 0.7 to 1.4 U/kg.BW increased the GV by 1.6 +/- 1.8 cm/yr (P < 0.006); increasing the GH dose from 1.4 to 2.1 U/kg.BW increased GV by 0.8 +/- 1.3 cm/yr (P = NS). The overall height gain during the 4-yr trial was 25.6 +/- 3.9 cm in the adapted dose group and 21.8 +/- 3.9 cm in the conventional group (P < 0.02). Final height (FH) results were obtained in 12 of 14 patients in the adapted dose group and all 17 patients in the conventional group and compared to the predicted FH using Lyon's method. The estimated height benefit was 10.6 +/- 3.8 cm in the adapted dose group compared to 5.2 +/- 3.7 cm in the conventional group (P < 0.01). Eighty-three percent of the patients in the adapted dose group had an FH superior or equal to -2 SD score for the general population compared to 29% in the conventional group. In conclusion, a marked increment in the GH dose in girls with Turner's syndrome associated with a relatively late age at introduction of estrogen therapy brought 83% of the patients into the lower range of the normal height distribution of the general population.