Bone and growth: basic principles behind rare disorders.

The heterogeneity of "rare bone disorders" can be explained by the number of molecules and regulatory pathways which are responsible for bone health and normal stature. In this article, the most important basic principles behind bone homeostasis from development to structure and regulation of the growing skeleton are summarized. The aim is to provide the reader with some theoretical background to understand the nature of the different main groups of disorders affecting bone stability, longitudinal growth and disturbances of calcium and phosphate homeostasis.

Alterations of bone material properties in adult patients with X-linked hypophosphatemia (XLH).

X-linked hypophosphatemia (XLH) caused by PHEX mutations results in elevated serum FGF23 levels, renal phosphate wasting and low 1,25-dihydroxyvitamin D. The glycophosphoprotein osteopontin, a potent inhibitor of mineralization normally degraded by PHEX, accumulates within the bone matrix. Conventional therapy consisting of supplementation with phosphate and vitamin D analogs is burdensome and the effects on bone material poorly characterized. We analyzed transiliac bone biopsies from four adult patients, two of them severely affected due to no diagnosis and no treatment until adulthood. We used light microscopy, qBEI and FTIRI to study histology, histomorphometry, bone mineralization density distribution, properties of the organic matrix and size of hypomineralized periosteocytic lesions. Non-treatment resulted in severe osteomalacia, twice the amount of mineralized trabecular volume, multiple osteon-like perforations, continuity of lamellae from mineralized to unmineralized areas and distinctive patches of woven bone. Periosteocytic lesions were larger than in treated patients. The latter had nearly normal osteoid thicknesses, although surface was still elevated. The median calcium content of the matrix was always within normal range, although the percentage of lowly mineralized bone areas was highly increased in non-treated patients, resulting in a marked heterogeneity in mineralization. Divalent collagen cross-links were evident independently of the mineral content of the matrix. Broad osteoid seams lacked measurable pyridinoline, a mature trivalent cross-link and exhibited considerable acidic lipid content, typically found in matrix vesicles. Based on our results, we propose a model that possibly integrates the relationship between the observed mineralization disturbances, FGF23 secretion and the known osteopontin accumulation in XLH.

Elevation of phosphate levels impairs skeletal myoblast differentiation.

Hyperphosphatemic conditions such as chronic kidney disease are associated with severe muscle wasting and impaired life quality. While regeneration of muscle tissue is known to be reliant on recruitment of myogenic progenitor cells, the effects of elevated phosphate loads on this process have not been investigated in detail so far. This study aims to clarify the direct effects of hyperphosphatemic conditions on skeletal myoblast differentiation in a murine in vitro model. C2C12 murine muscle progenitor cells were supplemented with phosphate concentrations resembling moderate to severe hyperphosphatemia (1.4-2.9 mmol/l). Phosphate-induced effects were quantified by RT-PCR and immunoblotting. Immunohistochemistry was performed to count nuclear positive cells under treatment. Cell viability and metabolic activity were assessed by XTT and BrdU incorporation assays. Inorganic phosphate directly induced ERK-phosphorylation in pre-differentiated C2C12 myoblast cells. While phosphate concentrations resembling the upper normal range significantly reduced Myogenin expression (- 22.5%, p = 0.015), severe hyperphosphatemic conditions further impaired differentiation (Myogenin - 61.0%, p < 0.0001; MyoD - 51.0%; p < 0.0001). Analogue effects were found on the protein level (Myogenin - 42.0%, p = 0.004; MyoD - 25.7%, p = 0.002). ERK inhibition strongly attenuated phosphate-induced effects on Myogenin expression (p = 0.002). Metabolic activity was unaffected by the treatments. Our data point to a phosphate-induced inhibition of myoblast differentiation without effects on cell viability. Serum phosphate levels as low as the upper normal serum range significantly impaired marker gene expression in vitro. Investigation of cellular effects of hyperphosphatemia may help to better define serum cutoffs and modify existing treatment approaches of phosphate binders, especially in patients at risk of sarcopenia.

Multidisciplinary patient care in X-linked hypophosphatemic rickets: one challenge, many perspectives.

X­linked hypophosphatemic rickets (XLH, OMIM #307800) is a rare genetic metabolic disorder caused by dysregulation of fibroblast-like growth factor 23 (FGF23) leading to profound reduction in renal phosphate reabsorption. Impaired growth, severe rickets and complex skeletal deformities are direct consequences of hypophosphatemia representing major symptoms of XLH during childhood. In adults, secondary complications including early development of osteoarthritis substantially impair quality of life and cause significant clinical burden. With the global approval of the monoclonal FGF23 antibody burosumab, a targeted treatment with promising results in phase III studies is available for children with XLH. Nevertheless, complete phenotypic rescue is rarely achieved and remaining multisystemic symptoms demand multidisciplinary specialist care. Coordination of patient management within the major medical disciplines is a mainstay to optimize treatment and reduce disease burden. This review aims to depict different perspectives in XLH patient care in the setting of a multidisciplinary centre of expertise for rare bone diseases.

Determining the normal range for IGF-I, IGFBP-3, and ALS: new reference data based on current internal standards.

BACKGROUND: The measurement of insulin-like growth factors (IGF-I) and insulin-like growth factor-binding protein (IGFBP-3) often serves as first-line testing in children with growth disorders. The role of acid-labile subunit (ALS) as a screening parameter for homozygous or heterozygous mutations of the ALS gene still has to be determined. METHODS: IGF-I, IGFBP-3, and ALS were measured in 252 samples from children and adolescents. Reference curves were fitted using generalized additive model for location, scale and shape (GAMLSS) models and SD-Scores were calculated. Bootstrap analysis was used to quantify the uncertainty of the estimated percentiles. Bland-Altman plots were used to investigate the discrepancy between our newly estimated standard deviation scores (SDS) and SDS calculated on the basis of previous reference data. RESULTS: We present reference data for enzyme-linked immunosorbent assay (ELISA) measurements based on recommended internal standard for IGF-I, IGFBP-3, and ALS suitable for calculation of SD-scores. The Bland-Altman plot shows a rough agreement between the previous SDS calculation and our new one only for SDS around 1; for SDS at -2, an average difference of 0.83 SD was noticed. CONCLUSION: Our IGF-I reference values for the interval of interest in diagnosing growth hormone deficiency (GHD) (prepubertal age) are solid as proved by bootstrap analysis. The difference in calculated SD scores by using data provided previously highlights the importance of using labor and method specific reference data.

Fibroblast growth factor 23 and Klotho are present in the growth plate.

INTRODUCTION: Regulation of phosphate homeostasis is essential for mineralization and enchondral ossification. Fibroblast growth factor 23 (FGF23) and its obligatory co-receptor Klotho (KL) play a key role in this process by influencing both renal phosphate reabsorption and vitamin D metabolism. In disease, excessive action of FGF23 leads to hypophosphatemic rickets, while its deficiency causes tumoral calcinosis. Although osteocytes and osteoblasts are widely seen as the primary source of FGF23 under physiological conditions, the origin of systemic FGF23 remains controversial. In this study, we investigated the expression of FGF23 and KL in porcine growth plate cartilage, adjacent tissues, and parenchymal tissues. MATERIALS AND METHODS: Tissue samples were obtained from 4- to 6-week-old piglets. mRNA expression was quantified by real-time PCR and normalized to 18S rRNA. Immunohistochemical staining was performed for FGF23, KL, collagen type X, and FGF receptor 1. Growth plate chondrocyte subpopulations were acquired by collagenase digestion of growth plate explants and subsequent density gradient centrifugation. RESULTS: We could detect both FGF23 and KL mRNA and protein in growth plate chondrocytes. FGF23 expression was mainly found in hypertrophic and resting chondrocytes. Furthermore, significant expression of both genes was observed in bone, liver, and spleen. CONCLUSION: These data challenge previous expression analyses, in particular theories of bone as the exclusive source of FGF23. Moreover, significant expression of FGF23 and KL within the growth plate and adjacent tissues imply a potential local role of FGF23 in chondrocyte differentiation and tissue mineralization.

Lifetime impact of achondroplasia study in Europe (LIAISE): findings from a multinational observational study.

BACKGROUND: Achondroplasia, caused by a pathogenic variant in the fibroblast growth factor receptor 3 gene, is the most common skeletal dysplasia. The Lifetime Impact of Achondroplasia Study in Europe (LIAISE; NCT03449368) aimed to quantify the burden of achondroplasia among individuals across a broad range of ages, including adults. METHODS: Demographic, clinical and healthcare resource use data were collected from medical records of achondroplasia patients enrolled in 13 sites across six European countries in this retrospective, observational study. Descriptive statistics or event rates per 100 person-years were calculated and compared across age groups as well as by history of limb lengthening. Patient-reported outcomes (quality of life [QoL], pain, functional independence, work productivity and activity impairments) were evaluated using questionnaires at the time of enrolment. An exploratory analysis investigated correlations between height (z-score or centimetres) and patient-reported outcomes. RESULTS: Overall, 186 study patients were included, with a mean age of 21.7 ± 17.3 years (range 5.0-84.4). At least one complication or surgery was reported for 94.6% and 72.0% of patients, respectively, at a rate of 66.6 and 21.5 events per 100 person-years. Diverse medical and surgical complications were reported for all ages in a bimodal distribution, occurring more frequently in the youngest and oldest age groups. A total of 40 patients had previously undergone limb lengthening (capped at 20% per the study protocol). The most frequent surgery types varied by age, in line with complication profiles. Healthcare resource use was high across all age groups, especially among the youngest and oldest individuals, and did not differ substantially according to history of limb lengthening. Compared to general population values, patients reported impaired QoL particularly for physical functioning domains. In addition, patients reported difficulty carrying out daily activities independently and pain starting in childhood. Patient height correlated with multiple patient-reported outcomes. CONCLUSIONS: The findings of this study suggest that, across an individual's lifetime, achondroplasia is associated with multisystem complications, reduced QoL and functionality, and increased pain. These results highlight the large amount of healthcare resources that individuals with achondroplasia require throughout their lifespans and provide novel insights into current achondroplasia management practices across Europe. Trial registration ClinicalTrials.gov, NCT03449368, Submitted 14 December 2017 - prospectively registered, https://clinicaltrials.gov/ct2/show/record/NCT03449368.

Acceleration in BMI gain following COVID-19 restrictions. A longitudinal study with 7- to 10-year-old primary school children.

BACKGROUND: The ramifications of COVID-19 restrictions might accelerate the already rising proportion of children with overweight or obesity. OBJECTIVES: To assess the association between COVID-19 restrictions and changes in body mass index (BMI) and the proportion of children with overweight or obesity. METHODS: Cohort study with baseline measurements in September 2019 (prior to COVID-19 restrictions) and follow-up in June 2020, September 2020, and March 2021 at 12 primary schools in Austria. The height and weight of 738 children aged 7 to 10 years were measured and age- and sex-specific national and international standardized values were calculated. Changes over time were analysed by analysis of variance. RESULTS: Mean BMIIOTF standard deviation scores (SDS) increased by 0.24 (95% CI, 0.21-0.28) between September 2019 and March 2021. The proportion of children with overweight or obesity increased from 20.7% to 26.2% during this period (p < 0.001) using national reference values-EQUI BMIAUT -comparable results were observed. Simultaneously, the heightAUT SDS increased by 0.06 (95% CI, 0.05-0.08) with a larger increase in girls (+0.11; p < 0.001) than in boys (+0.03; p = 0.19). CONCLUSIONS: COVID-19 restrictions were associated with accelerated increases in mean BMI and the proportion of children with overweight or obesity. The increase in height SDS in girls calls for further investigations.

Persistent Lower Limb Deformities Despite Amelioration of Rickets in X-Linked Hypophosphatemia (XLH) - A Prospective Observational Study.

Background: Gait deviations, lower limb pain and joint stiffness represent key symptoms in patients with X-linked hypophosphatemia (XLH, OMIM 307800), a rare disorder of mineral homeostasis. While the pathomechanism for rickets is well understood, the direct role of PHEX (Phosphate-regulating neutral endopeptidase) deficiency in non-rachitic features including complex deformities, skull and dental affections remains unclear. FGF23-inhibiting antibody treatment can normalize serum phosphate levels and to improve rickets in XLH patients. However, linear growth remains impaired and effects on lower limb deformity and gait are insufficiently studied. Aims: To characterize and evaluate the course of lower limb deformity in a case series of pediatric XLH patients receiving Burosumab therapy. Methods: Comparative assessment of planar radiographs, gait analysis, biochemical and clinical features of pediatric patients before and ≥12 months after initiation of FGF23-inhibiting was performed prospectively. Lower limb maltorsion was quantified by torsional MRI and gait analysis. Standardized deformity analysis of lower limb anteroposterior radiographs was conducted. Results: Seven patients (age 9.0 +/-3.6 years) were eligible for this study. All patients received conventional treatment before onset of antibody treatment. Maltorsion of the femur was observed in 8/14 legs using torsional MRI (mean antetorsion 8.79°). Maltorsion of the tibia was observed in 9/14 legs (mean external torsion 2.8°). Gait analysis confirmed MRI findings with femoral external malrotation prior to and one year after onset of Burosumab therapy. Internal foot progression (intoeing gait) remained pathological in all cases (mean 2.2°). Knee rotation was pathologically internal 10/14 legs. Mean mechanical axis deviation (MAD) of 16.1mm prior to Burosumab changed in average by 3.9mm. Three children underwent guided growth procedures within the observation period. Mild postprocedural rebound of frontal axis deviation was observed under Burosumab treatment in one patient. Conclusions: This is the first study to investigate lower limb deformity parameters quantitatively in children with XLH receiving Burosumab. One year of Burosumab therapy was associated with persistent maltorsion and frontal axis deviation (varus/valgus) despite improved rickets in this small, prospective uncontrolled study.

A neomorphic variant in SP7 alters sequence specificity and causes a high-turnover bone disorder.

SP7/Osterix is a transcription factor critical for osteoblast maturation and bone formation. Homozygous loss-of-function mutations in SP7 cause osteogenesis imperfecta type XII, but neomorphic (gain-of-new-function) mutations of SP7 have not been reported in humans. Here we describe a de novo dominant neomorphic missense variant (c.926 C > G:p.S309W) in SP7 in a patient with craniosynostosis, cranial hyperostosis, and long bone fragility. Histomorphometry shows increased osteoblasts but decreased bone mineralization. Mice with the corresponding variant also show a complex skeletal phenotype distinct from that of Sp7-null mice. The mutation alters the binding specificity of SP7 from AT-rich motifs to a GC-consensus sequence (typical of other SP family members) and produces an aberrant gene expression profile, including increased expression of Col1a1 and endogenous Sp7, but decreased expression of genes involved in matrix mineralization. Our study identifies a pathogenic mechanism in which a mutation in a transcription factor shifts DNA binding specificity and provides important in vivo evidence that the affinity of SP7 for AT-rich motifs, unique among SP proteins, is critical for normal osteoblast differentiation.

Growth pattern in children with X-linked hypophosphatemia treated with burosumab and growth hormone.

BACKGROUND: X-linked hypophosphatemia (XLH) is characterized by increased serum concentrations of fibroblast growth factor 23 (FGF23), hypophosphatemia and insufficient endogenous synthesis of calcitriol. Beside rickets, odonto- and osteomalacia, disproportionate short stature is seen in most affected individuals. Vitamin D analogs and phosphate supplements, i.e., conventional therapy, can improve growth especially when started early in life. Recombinant human growth hormone (rhGH) therapy in XLH children with short stature has positive effects, although few reports are available. Newly available treatment (burosumab) targeting increased FGF23 signaling leads to minimal improvement of growth in XLH children. So far, we lack data on the growth of XLH children treated with concomitant rhGH and burosumab therapies. RESULTS: Thirty-six patients received burosumab for at least 1 year after switching from conventional therapy. Of these, 23 received burosumab alone, while the others continued rhGH therapy after switching to burosumab. Children treated with burosumab alone showed a minimal change in height SDS after 1 year (mean ± SD 0.0 ± 0.3 prepubertal vs. 0.1 ± 0.3 pubertal participants). In contrast, rhGH clearly improved height during the first year of treatment before initiating burosumab (mean ± SD of height gain 1.0 ± 0.4); patients continued to gain height during the year of combined burosumab and rhGH therapies (mean ± SD height gain 0.2 ± 0.1). As expected, phosphate serum levels normalized upon burosumab therapy. No change in serum calcium levels, urinary calcium excretion, or 25-OHD levels was seen, though 1,25-(OH)2D increased dramatically under burosumab therapy. CONCLUSION: To our knowledge, this is the first study on growth under concomitant rhGH and burosumab treatments. We did not observe any safety issue in this cohort of patients which is one of the largest in Europe. Our data suggest that continuing treatment with rhGH after switching from conventional therapy to burosumab, if the height prognosis is compromised, might be beneficial for the final height.

Lower Limb Deformity and Gait Deviations Among Adolescents and Adults With X-Linked Hypophosphatemia.

Background: X-linked hypophosphatemia (XLH) is a rare genetic disorder characterized by lower limb deformity, gait and joint problems, and pain. Hence, quality of life is substantially impaired. This study aimed to assess lower limb deformity, specific radiographic changes, and gait deviations among adolescents and adults with XLH. Design: Data on laboratory examination and gait analysis results were analyzed retrospectively. Deformities, osteoarthritis, pseudofractures, and enthesopathies on lower limb radiographs were investigated. Gait analysis findings were compared between the XLH group and the control group comprising healthy adults. Patients and Controls: Radiographic outcomes were assessed retrospectively in 43 patients with XLH (28 female, 15 male). Gait analysis data was available in 29 patients with confirmed XLH and compared to a healthy reference cohort (n=76). Results: Patients with XLH had a lower gait quality compared to healthy controls (Gait deviation index GDI 65.9% +/- 16.2). About 48.3% of the study population presented with a greater lateral trunk lean, commonly referred to as waddling gait. A higher BMI and mechanical axis deviation of the lower limbs were associated with lower gait scores and greater lateral trunk lean. Patients with radiologic signs of enthesopathies had a lower GDI. Conclusions: This study showed for the first time that lower limb deformity, BMI, and typical features of XLH such as enthesopathies negatively affected gait quality among adolescents and adults with XLH.

Lethal Encephalopathy in an Infant with Hypophosphatasia despite Enzyme Replacement Therapy.

Hypophosphatasia (HPP) is an inborn error of metabolism caused by loss-of-function mutations in the biomineralization-associated alkaline phosphatase gene, encoding tissue-nonspecific alkaline phosphatase (TNSALP). Symptoms include skeletal hypomineralization and extra-skeletal manifestations such as pyridoxine (B6)-responsive seizures due to impaired cerebral B6 passage. Since the introduction of enzyme replacement therapy (ERT), skeletal manifestations and B6-responsive seizures were reported to improve significantly. Nevertheless, there is an increasing evidence of B6-independent neurological manifestation of HPP including HPP-associated encephalopathy. Here, we present for the first time the brain alterations of an infant with neonatal HPP who died of neurological complications at the age of 5 months despite early initiation of ERT. CSF analysis showed normal concentrations of biogenic amines reflecting sufficient intracellular B6 availability. Postmortem histopathology revealed severe, localized affection of the cerebral cortex including cortical lesions in layers 2 and 3 in direct proximity to TNSALP-expressing neurons and hippocampal sclerosis. Our findings confirm that TNSALP deficiency may lead to a severe encephalopathy. We hypothesize that HPP-associated encephalopathy resistant to currently available ERT may develop in addition and probably independently of typical B6-responsive seizures in some patients. Prospective, controlled studies with close neurological follow-up including brain imaging are needed to identify patients at risk for severe neurological symptoms despite ERT.

Disease-specific gait deviations in pediatric patients with X-linked hypophosphatemia.

BACKGROUND: X-linked hypophosphatemia (XLH) represents the most common genetic form of rickets featuring profound hypophosphatemia with associated skeletal and non-skeletal manifestations. Early onset gait disturbances contribute strongly to the burden of disease. However, no study has comprehensively characterized naturally occurring gait deviations in pediatric patients with XLH. RESEARCH QUESTIONS: Can disease-specific gait deviations and potentially influencing factors be identified by gait analysis in non-surgically treated children with XLH? METHODS: Gait laboratory assessments of 12 pediatric patients with XLH without previous long bone surgery was retrospectively analyzed and compared to age-matched healthy controls. Radiologic and clinical parameters of XLH patients were correlated with kinematic gait variables and gait scores. RESULTS: Reduced external knee rotation and increased external hip orientation was ubiquitous in children with XLH. Increased lateral trunk lean, or "waddling gait", occurred in five children and was associated with varus knee deformities. Overall, children with XLH showed a reduced Gait Deviation Index (GDI) compared to controls. Radiologic and gait analysis revealed complex combined frontal and torsional deformity of the lower limbs as a common feature in XLH. Higher Body Mass Index (BMI) was associated with both lateral trunk lean and impaired GDI. SIGNIFICANCE: Gait analysis is feasible to quantify gait deviations and lower limb deformities in pediatric patients with XLH. Specific gait characteristics including internal knee rotation and external hip rotation are common among patients with XLH and contribute to impaired gait scores. Our data suggest the use of gait and deformity data assessment as outcome parameters in future observational and interventional studies. Standardized assessment might contribute to targeted treatments to improve life quality in XLH patients.

Diagnostic Value of Serum Acid-Labile Subunit Alone and in combination with IGF-I and IGFBP-3 in the Diagnosis of Growth Hormone Deficiency.

BACKGROUND: The acid-labile subunit (ALS) is a crucial factor in the tertiary complex. IGF-I and IGFBP-3 are routinely measured during the diagnostic work-up for growth hormone deficiency (GHD). The aim of the study is to evaluate the relevance of serum ALS as an additional biomarker in the diagnosis of GHD. METHODS: Ninety-one children undergoing standard diagnostic work-up for GHD were included in this retrospective study. Inclusion criteria were evidence-based auxological cutoffs, IGF-I and IGFBP-3 <-2 SDS at first presentation, at least 1 growth hormone (GH) stimulation test, and IGF-I, IGFBP-3, and ALS measurements on the same day. Statistical analysis was performed by ROC as well as by odds ratio calculations. RESULTS: Forty-seven of 90 participants presented with peak GH values under the cutoff of 7 ng/mL. AUC from a model containing only IGF-I was 0.76 and 0.68 when using only ALS. A model containing IGF-I, IGFBP-3, and ALS (AUC = 0.77) did not improve the result compared to the combination of IGF-I/IGFBP-3 (0.77) or IGF-I/ALS (0.76). Furthermore, the variation in the outcome (GH peak

Impact of 3D-culture on the expression of differentiation markers and hormone receptors in growth plate chondrocytes as compared to articular chondrocytes.

In this study we compared the expression of hormone receptors and markers of differentiation in growth plate chondrocytes (GPC) and articular chondrocytes (AC) under different culture conditions by real-time PCR and immunofluorescence. After one week of monolayer culture, porcine GPC and AC of 6-8-week-old piglets were either seeded in alginate beads or further grown in monolayer culture up to 5 weeks. During monolayer culture the expression of Col2, Col1, Col10, aggrecan, ERalpha and ERbeta decreased dramatically, whereas culture in alginate beads restored an expression pattern similar to native tissue. The receptors IGF-1R, IGF-2R and GHR were, however, increased in monolayer culture compared to alginate culture or native tissue. The relative proportion of ERalpha and ERbeta expression was different in GPC when compared to AC. All of our results on mRNA expression during culture in alginate beads were also verified to be translated to the protein level. Thus, the expression of hormone rereptors and differentiation markers were found to be highly influenced by culture conditions. Moreover, the porcine model is promising as defined by tissue availability, expression of relevant hormonal receptors and comparability to human conditions, in particular in the area of basic growth research.

BMP15 mutations in XX gonadal dysgenesis and premature ovarian failure.

OBJECTIVE: Premature ovarian failure (POF) is a heterogeneous group of diseases with amenorrhea before the age of 40 years and elevated gonadotropins. Recently, heterozygous mutations in the X-linked gene encoding bone morphogenetic protein-15 (BMP15) have been identified as a possible cause of ovarian failure. STUDY DESIGN: Molecular analysis of BMP15, growth differentiation factor-9 (GDF9), and follicle-stimulating hormone receptor (FSHR) in patients with ovarian failure. RESULTS: We can show that a BMP15 alteration, previously described as a mutation, is instead a polymorphism. A digenic inheritance of POF including BMP15 and FSHR is unlikely. Mutations in GDF9 could not be detected. CONCLUSION: Caution is recommended in the interpretation of BMP15 mutations in the context of POF.

Health status, quality of life and medical care in adult women with Turner syndrome.

BACKGROUND: Previous studies have shown that only a minority of patients with Turner syndrome (TS) have adequate medical care after transfer to adult care. AIM OF THIS STUDY: To assess the status of medical follow-up and quality of life (QoL) in adult women diagnosed with TS and followed up until transfer. To compare the subjective and objective view of the medical care quality and initiate improvements based on patients' experiences and current recommendations. METHODS: 39 adult women with TS out of 64 patients contacted were seen for a clinical and laboratory check, cardiac ultrasound, standardized and structured questionnaires (SF-36v2 and Beck depression inventory). RESULTS: 7/39 of the patients were not being followed medically at all. Only 2/39 consulted all the specialists recommended. Comorbidities were newly diagnosed in 27/39 patients; of these, 11 related to the cardiovascular system. Patients in our cohort scored as high as the mean reference population for SF-36v2 in both mental and physical compartments. Obese participants had lower scores in the physical function section, whereas higher education was related to higher physical QoL scores. Adult height slightly correlated positively with physical health. CONCLUSION: Medical follow-up was inadequate in our study cohort of adults with TS. Even though their medical follow-up was insufficient, these women felt adequately treated, leaving them vulnerable for premature illness. Initiatives in health autonomy and a structured transfer process as well as closer collaborations within specialities are urgently needed.

Primary growth hormone (GH) insensitivity and insulin-like growth factor deficiency caused by novel compound heterozygous mutations of the GH receptor gene: genetic and functional studies of simple and compound heterozygous states.

CONTEXT: Primary GH insensitivity (GHI) or Laron syndrome, caused by mutations of the GH receptor (GHR) gene, has a clinical phenotype of postnatal growth failure associated with normal elevated serum concentrations of GH and low serum levels of IGF-I. OBJECTIVE: We investigated the clinical and biochemical implications of molecular defects in the GHR gene in an Austrian family with two daughters who were GHI. PATIENTS: Patient 1 [height, -4.8 sd score (SDS)] and patient 2 (height, -5.0 SDS) had elevated circulating levels of GH, low-normal levels of GH-binding protein, and abnormally low IGF-I (-5.0 SDS and -2.6 SDS, respectively) and IGF-binding protein-3 (-2.6 SDS and -2.0 SDS, respectively). RESULTS: Both patients carry novel compound, missense, heterozygous GHR mutations, C94S and H150Q. In vitro reconstitution experiments demonstrated that whereas each of the mutants could be stably expressed, GHR(C94S) lost its affinity for GH and could neither activate signal transducer and activator of transcription (STAT)-5b nor drive STAT5b-dependent gene transcription in response to GH (1-100 ng/ml). GHR(H150Q) showed normal affinity for GH but impaired capacity for signal transduction. The compound heterozygote and C94S heterozygote, but not the H150Q heterozygote, showed significant deficiency in activating GH-induced gene expression, corroborating diminished GH-induced STAT5b activation in fibroblasts carrying GHR(C94S) as either a compound heterozygote (in the patients) or a simple heterozygote (in one parent). CONCLUSIONS: Each of the compound heterozygous mutations contributed additively to the pathological condition seen in the patients, and the more detrimental of the two mutations, C94S, may cause (partial) primary GHI, even in a heterozygous state.