Health-related quality of life of children with X-linked hypophosphatemia in Germany.

BACKGROUND: X-linked hypophosphatemia (XLH) is a rare inherited phosphate-wasting disorder associated with bone and dental complications. Health-related quality of life (HRQoL) is reduced in XLH patients on conventional treatment with phosphate supplements and active vitamin D, while information on patients treated with burosumab is rare. METHODS: HRQoL was assessed in 63 pediatric XLH patients participating in a prospective, observational study and patient registry in Germany using the KIDSCREEN-52 survey instrument and standardized qualitative interviews. RESULTS: The median age of the XLH patients was 13.2 years (interquartile range 10.6 - 14.6). At the time of the survey, 55 (87%) patients received burosumab and 8 (13%) conventional treatment. Forty-six patients (84%) currently being treated with burosumab previously received conventional treatment. Overall, HRQoL was average compared to German reference values (mean ± SD: self-report, 53.36 ± 6.47; caregivers' proxy, 51.33 ± 7.15) and even slightly above average in some dimensions, including physical, mental, and social well-being. In general, XLH patients rated their own HRQoL higher than their caregivers. In qualitative interviews, patients and caregivers reported that, compared with conventional therapy, treatment with burosumab reduced stress, bone pain, and fatigue, improved physical health, and increased social acceptance by peers and the school environment. CONCLUSIONS: In this real-world study in pediatric XLH patients, HRQoL was average or even slightly above that of the general population, likely due to the fact that the vast majority of patients had their treatment modality switched from conventional treatment to burosumab resulting in improved physical health and well-being.

Quantitative Characterization of Ectopic Adrenal Gene Expression in Fetal Testes in 21-Hydroxylase Deficient Mice.

Testicular adrenal rest tumors (TART) are a frequent and fertility impairing long-term complication in males with classic congenital adrenal hyperplasia. Due to lack of clear experimental data on their origin, they are hypothesized to be derived from ectopic adrenocortical cells within testicular tissue mainly growing upon stimulation by chronically elevated levels of adrenocorticotropin (ACTH). Alternatively, a more totipotent embryological origin has been discussed as the potential source of these tumors. The aim of this study was to quantify alterations of ectopic expression of adrenocortical genes (CYP11B1, CYP11B2, CYP21, MC2R) and the Leydig cell specific marker (INSL3) in testicular tissue of fetal 21-hydroxylase deficient (21OHD) mice. Timed-pregnancy studies were performed using H-2aw18 (aw18)-mice. Testes and adrenals of E15.5 and E18.5 mouse fetuses were used for real-time PCR and immunohistochemistry. Gene expression levels were analyzed for genotype-dependent alterations and compared with immunohistochemistry. While enzymes of steroidogenesis showed a significant increased expression in adrenals of 21OHD mice at both E15.5 and E18.5 compared to wild-type (WT) mice, expression levels were unaltered in testes of 21OHD mice. When compared to WT adrenals a significant increase of INSL3 expression in adrenals of 21OHD mice at E15.5 and E18.5 was detected. Cells with adrenocortical properties in mice fetal testis differ from in situ adrenocortical cells in gene expression and growth at E15.5 and E18.5. These findings suggest that the different local regulation and different local niche in adrenals and testes influence growth of aberrant adrenal cells.

[Long-term morbidity in congenital adrenal hyperplasia]. / Langzeitmorbidität beim adrenogenitalen Syndrom.

Congenital adrenal hyperplasia (CAH) is one of the most common autosomal recessive disorders and is characterized by cortisol deficiency. The most common cause of CAH is a mutation in the CYP21A2 gene, resulting in 21-hydroxylase deficiency in the adrenal cortex. The lack of cortisol causes an increase in adrenocorticotropic hormone (ACTH), which in turn results in an excess of adrenal androgens. Aldosterone synthesis may also be impaired. The clinical manifestation of CAH depends on the residual activity of 21-hydroxylase and the subsequent lack of cortisol and adrenal androgen excess. While classic CAH is a potentially life-threatening condition, non-classic CAH is mild to asymptomatic. Therapy of classic CAH consists of glucocorticoid and mineralocorticoid substitution. Despite optimization of therapy, CAH still leads to increased morbidity and mortality in patients. The clinical consequences of androgen excess in affected women range from intrauterine virilisation of external genitalia in classic CAH patients to mild symptoms of hyperandrogenism in non-classic forms. Increased demand for cortisol during illness or physical and psychological stress situations can trigger life-threatening adrenal crises. As current glucocorticoid therapy cannot mimic the physiological circadian rhythm and is usually supraphysiological in dose to control androgen excess, therapy-associated long-term consequences such as decreased bone health and an increased cardiometabolic risk profile are common. The burden of the disease may also lead to impaired quality of life and mental health. For this reason, regular screening and follow-up of patients with CAH should be performed in specialized centers to detect and treat possible comorbidities at an early stage.

Effect of androgen excess and glucocorticoid exposure on metabolic risk profiles in patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency.

Data on cardiovascular morbidity in adults with congenital adrenal hyperplasia (CAH) is sparse. We therefore aimed to determine the role of androgen control and glucocorticoid therapy on metabolic health. For that purpose, we included 90 patients (N = 39 men, N = 51 women) with classic CAH due to 21-hydroxylase deficiency (N = 61 salt wasting, N = 29 simple virilizing) and an equal number of controls matched for age, sex, BMI and smoking-habits. We could show that there was no difference in intima-media-thickness between patients and controls and only one patient fulfilled all criteria of the metabolic syndrome. CAH men presented with an increased relative body fat mass in comparison to controls (25.6 % vs. 22.1 %; p = 0.011) while this was not true for CAH women. Body fat was lower in those taking hydrocortisone instead of synthetic glucocorticoids (B = -3.27; p = 0.048). While arterial hypertension was rare, 54 % of patients had an impaired systolic drop at night or were classified as non-dippers (17 %). Impaired dipping was not associated with evening glucocorticoid and fludrocortisone intake but mediated by sodium levels. Insulin resistance was more common in CAH women (B = 1.689; p = 0.036) and in those with poor androgen control (B = 0.823; p = 0.046). In summary, we could show that good cardiovascular health outcome in adult CAH patients can be achieved. Hydrocortisone is superior in terms of body composition. It is yet unclear how non-dipping will translate into cardiovascular morbidity in the long-term.

Clinical long-time course, novel mutations and genotype-phenotype correlation in a cohort of 27 families with POMT1-related disorders.

BACKGROUND: The protein O-mannosyltransferase 1, encoded by the POMT1 gene, is a key enzyme in the glycosylation of α-dystroglycan. POMT1-related disorders belong to the group of dystroglycanopathies characterized by a proximally pronounced muscular dystrophy with structural or functional involvement of the brain and/or the eyes. The phenotypic spectrum ranges from the severe Walker-Warburg syndrome (WWS) to milder forms of limb girdle muscular dystrophy (LGMD). The phenotypic severity of POMT1-related dystroglycanopathies depends on the residual enzyme activity. A genotype-phenotype correlation can be assumed. RESULTS: The clinical, neuroradiological, and genetic findings of 35 patients with biallelic POMT1 mutations (15 WWS, 1 MEB (muscle-eye-brain disease), 19 LGMD) from 27 independent families are reported. The representative clinical course of an infant with WWS and the long-term course of a 32 years old patient with LGMD are described in more detail. Specific features of 15 patients with the homozygous founder mutation p.Ala200Pro are defined as a distinct and mildly affected LGMD subgroup. Ten previously reported and 8 novel POMT1 mutations were identified. Type and location of each of the POMT1 mutations are evaluated in detail and a list of all POMT1 mutations reported by now is provided. Patients with two mutations leading to premature protein termination had a WWS phenotype, while the presence of at least one missense mutation was associated with milder phenotypes. In the patient with MEB-like phenotype two missense mutations were observed within the catalytic active domain of the enzyme. CONCLUSIONS: Our large cohort confirms the importance of type and location of each POMT1 mutation for the individual clinical manifestation and thereby expands the knowledge on the genotype-phenotype correlation in POMT1-related dystroglycanopathies. This genotype-phenotype correlation is further supported by the observation of an intrafamiliar analogous clinical manifestation observed in all affected 13 siblings from 5 independent families. Our data confirm the progressive nature of the disease also in milder LGMD phenotypes, ultimately resulting in loss of ambulation at a variable age. Our data define two major clinical POMT1 phenotypes, which should prompt genetic testing including the POMT1 gene: patients with a severe WWS manifestation predominantly present with profound neonatal muscular hypotonia and a severe and progressive hydrocephalus with involvement of brainstem and/or cerebellum. The presence of an occipital encephalocele in a WWS patient might point to POMT1 as causative gene within the different genes associated with WWS. The milder LGMD phenotypes constantly show markedly elevated creatine kinase values in combination with microcephaly and cognitive impairment.

Sodium Chloride Supplementation Is Not Routinely Performed in the Majority of German and Austrian Infants with Classic Salt-Wasting Congenital Adrenal Hyperplasia and Has No Effect on Linear Growth and Hydrocortisone or Fludrocortisone Dose.

INTRODUCTION: Sodium chloride supplementation in salt-wasting congenital adrenal hyperplasia (CAH) is generally recommended in infants, but its implementation in routine care is very heterogeneous. OBJECTIVE: To evaluate oral sodium chloride supplementation, growth, and hydrocortisone and fludrocortisone dose in infants with salt-wasting CAH due to 21-hydroxylase in 311 infants from the AQUAPE CAH database. RESULTS: Of 358 patients with classic CAH born between 1999 and 2015, 311 patients had salt-wasting CAH (133 females, 178 males). Of these, 86 patients (27.7%) received oral sodium chloride supplementation in a mean dose of 0.9 ± 1.4 mmol/kg/day (excluding nutritional sodium content) during the first year of life. 225 patients (72.3%) were not treated with sodium chloride. The percentage of sodium chloride-supplemented patients rose from 15.2% in children born 1999-2004 to 37.5% in children born 2011-2015. Sodium chloride-supplemented and -unsupplemented infants did not significantly differ in hydrocortisone and fludrocortisone dose, target height-corrected height-SDS, and BMI-SDS during the first 2 years of life. CONCLUSION: In the AQUAPE CAH database, approximately one-third of infants with salt-wasting CAH receive sodium chloride supplementation. Sodium chloride supplementation is performed more frequently in recent years. However, salt supplementation had no influence on growth, daily fludrocortisone and hydrocortisone dose, and frequency of adrenal crisis.

Homozygous ARHGEF2 mutation causes intellectual disability and midbrain-hindbrain malformation.

Mid-hindbrain malformations can occur during embryogenesis through a disturbance of transient and localized gene expression patterns within these distinct brain structures. Rho guanine nucleotide exchange factor (ARHGEF) family members are key for controlling the spatiotemporal activation of Rho GTPase, to modulate cytoskeleton dynamics, cell division, and cell migration. We identified, by means of whole exome sequencing, a homozygous frameshift mutation in the ARHGEF2 as a cause of intellectual disability, a midbrain-hindbrain malformation, and mild microcephaly in a consanguineous pedigree of Kurdish-Turkish descent. We show that loss of ARHGEF2 perturbs progenitor cell differentiation and that this is associated with a shift of mitotic spindle plane orientation, putatively favoring more symmetric divisions. The ARHGEF2 mutation leads to reduction in the activation of the RhoA/ROCK/MLC pathway crucial for cell migration. We demonstrate that the human brain malformation is recapitulated in Arhgef2 mutant mice and identify an aberrant migration of distinct components of the precerebellar system as a pathomechanism underlying the midbrain-hindbrain phenotype. Our results highlight the crucial function of ARHGEF2 in human brain development and identify a mutation in ARHGEF2 as novel cause of a neurodevelopmental disorder.

Computational analysis of liquid chromatography-tandem mass spectrometric steroid profiling in NCI H295R cells following angiotensin II, forskolin and abiraterone treatment.

Adrenal steroid hormones, which regulate a plethora of physiological functions, are produced via tightly controlled pathways. Investigations of these pathways, based on experimental data, can be facilitated by computational modeling for calculations of metabolic rate alterations. We therefore used a model system, based on mass balance and mass reaction equations, to kinetically evaluate adrenal steroidogenesis in human adrenal cortex-derived NCI H295R cells. For this purpose a panel of 10 steroids was measured by liquid chromatographic-tandem mass spectrometry. Time-dependent changes in cell incubate concentrations of steroids - including cortisol, aldosterone, dehydroepiandrosterone and their precursors - were measured after incubation with angiotensin II, forskolin and abiraterone. Model parameters were estimated based on experimental data using weighted least square fitting. Time-dependent angiotensin II- and forskolin-induced changes were observed for incubate concentrations of precursor steroids with peaks that preceded maximal increases in aldosterone and cortisol. Inhibition of 17-alpha-hydroxylase/17,20-lyase with abiraterone resulted in increases in upstream precursor steroids and decreases in downstream products. Derived model parameters, including rate constants of enzymatic processes, appropriately quantified observed and expected changes in metabolic pathways at multiple conversion steps. Our data demonstrate limitations of single time point measurements and the importance of assessing pathway dynamics in studies of adrenal cortical cell line steroidogenesis. Our analysis provides a framework for evaluation of steroidogenesis in adrenal cortical cell culture systems and demonstrates that computational modeling-derived estimates of kinetic parameters are an effective tool for describing perturbations in associated metabolic pathways.

A novel hemizygous mutation of MAMLD1 in a patient with 46,XY complete gonadal dysgenesis.

MAMLD1 is suggested to play a role in the development of 46,XY disorders of sexual development (46,XY DSD). So far, mutations in this gene have been detected in several cases of hypospadias with normal testosterone levels at birth. From in vitro studies it was concluded that Mamld1 might transiently affect testosterone synthesis during genital development. We describe the first MAMLD1 mutation in a 46,XY patient with complete gonadal dysgenesis. The novel MAMLD1 missense mutation (p.P677L) results in a severely reduced transactivation in vitro of the promoter of the MAMLD1 target gene HES3/Hes3. However, as knowledge about the functional role of MAMLD1 in gonadal development is limited, we suggest that additional factors (digenic or oligogenic cause) play a role in the development of complete gonadal dysgenesis in this patient.

Novel deletion of lysine 7 expands the clinical, histopathological and genetic spectrum of TPM2-related myopathies.

The ß-tropomyosin gene encodes a component of the sarcomeric thin filament. Rod-shaped dimers of tropomyosin regulate actin-myosin interactions and ß-tropomyosin mutations have been associated with nemaline myopathy, cap myopathy, Escobar syndrome and distal arthrogryposis types 1A and 2B. In this study, we expand the allelic spectrum of ß-tropomyosin-related myopathies through the identification of a novel ß-tropomyosin mutation in two clinical contexts not previously associated with ß-tropomyosin. The first clinical phenotype is core-rod myopathy, with a ß-tropomyosin mutation uncovered by whole exome sequencing in a family with autosomal dominant distal myopathy and muscle biopsy features of both minicores and nemaline rods. The second phenotype, observed in four unrelated families, is autosomal dominant trismus-pseudocamptodactyly syndrome (distal arthrogryposis type 7; previously associated exclusively with myosin heavy chain 8 mutations). In all four families, the mutation identified was a novel 3-bp in-frame deletion (c.20_22del) that results in deletion of a conserved lysine at the seventh amino acid position (p.K7del). This is the first mutation identified in the extreme N-terminus of ß-tropomyosin. To understand the potential pathogenic mechanism(s) underlying this mutation, we performed both computational analysis and in vivo modelling. Our theoretical model predicts that the mutation disrupts the N-terminus of the α-helices of dimeric ß-tropomyosin, a change predicted to alter protein-protein binding between ß-tropomyosin and other molecules and to disturb head-to-tail polymerization of ß-tropomyosin dimers. To create an in vivo model, we expressed wild-type or p.K7del ß-tropomyosin in the developing zebrafish. p.K7del ß-tropomyosin fails to localize properly within the thin filament compartment and its expression alters sarcomere length, suggesting that the mutation interferes with head-to-tail ß-tropomyosin polymerization and with overall sarcomeric structure. We describe a novel ß-tropomyosin mutation, two clinical-histopathological phenotypes not previously associated with ß-tropomyosin and pathogenic data from the first animal model of ß-tropomyosin-related myopathies.

Hexosamine biosynthetic pathway mutations cause neuromuscular transmission defect.

Neuromuscular junctions (NMJs) are synapses that transmit impulses from motor neurons to skeletal muscle fibers leading to muscle contraction. Study of hereditary disorders of neuromuscular transmission, termed congenital myasthenic syndromes (CMS), has helped elucidate fundamental processes influencing development and function of the nerve-muscle synapse. Using genetic linkage, we find 18 different biallelic mutations in the gene encoding glutamine-fructose-6-phosphate transaminase 1 (GFPT1) in 13 unrelated families with an autosomal recessive CMS. Consistent with these data, downregulation of the GFPT1 ortholog gfpt1 in zebrafish embryos altered muscle fiber morphology and impaired neuromuscular junction development. GFPT1 is the key enzyme of the hexosamine pathway yielding the amino sugar UDP-N-acetylglucosamine, an essential substrate for protein glycosylation. Our findings provide further impetus to study the glycobiology of NMJ and synapses in general.

[Calpain-3 gene defect causing limb gird muscular dystrophy in a Hungarian family]. / Végtagövi izomdisztrófiát okozó kalpaindefektus egy magyar családban.

Limb gird muscular dystrophies (LGMD2) are a clinically and genetically heterogeneous group of hereditary diseases with autosomal recessive trait, characterized by progressive atrophy and weakness predominantly in the proximal limb muscles. The authors present clinical, histological, immunohistochemical and immunoblot results of two sisters suffering from so far unclassified autosomal recessive limb girdle muscular dystrophy. Haplotype analysis for genes possibly involved in autosomal recessive limb girdle muscular dystrophies was performed in the genetically informative family. All of the results pointed to a molecular genetic defect of the calpain-3 (CAPN3) gene. Direct sequencing of the CAPN3 gene revealed compound heterozygous state for two mutations previously described in association with limb girdle muscular dystrophy, proving pathogenicity. The authors would like to emphasize the importance of the above described combined strategy in diagnosing limb girdle muscular dystrophies.