Secondary use of patient data within decentralized studies using the example of rare diseases in Germany: A data scientist's exploration of process and lessons learned.

Objective: Unlocking the potential of routine medical data for clinical research requires the analysis of data from multiple healthcare institutions. However, according to German data protection regulations, data can often not leave the individual institutions and decentralized approaches are needed. Decentralized studies face challenges regarding coordination, technical infrastructure, interoperability and regulatory compliance. Rare diseases are an important prototype research focus for decentralized data analyses, as patients are rare by definition and adequate cohort sizes can only be reached if data from multiple sites is combined. Methods: Within the project "Collaboration on Rare Diseases", decentralized studies focusing on four rare diseases (cystic fibrosis, phenylketonuria, Kawasaki disease, multisystem inflammatory syndrome in children) were conducted at 17 German university hospitals. Therefore, a data management process for decentralized studies was developed by an interdisciplinary team of experts from medicine, public health and data science. Along the process, lessons learned were formulated and discussed. Results: The process consists of eight steps and includes sub-processes for the definition of medical use cases, script development and data management. The lessons learned include on the one hand the organization and administration of the studies (collaboration of experts, use of standardized forms and publication of project information), and on the other hand the development of scripts and analysis (dependency on the database, use of standards and open source tools, feedback loops, anonymization). Conclusions: This work captures central challenges and describes possible solutions and can hence serve as a solid basis for the implementation and conduction of similar decentralized studies.

Markers of Fertility in Adolescents With Chronic Endocrinopathies at Transition From Paediatric to Adult Care.

OBJECTIVE: During the process of transition from paediatric to adult health care, counselling concerning fertility is an important issue and is based mainly on serum markers of gonadal function. Here, we analysed these markers in adolescents with various underlying endocrine diseases at the time of transition. METHODS: After reaching near adult height and late puberty (girls: bone age [BA] ≥14 years, and boys: BA ≥16 years), we assessed stages of puberty according to Tanner and measured testes or ovarian volumes and serum markers of gonadal function (anti-Mullerian hormone [AMH], inhibin B, 17ß-estradiol, testosterone). RESULTS: One hundred and ten patients (56 females and 54 males) were included from May 2010 to March 2016 with multiple pituitary hormone deficiency (MPHD; n = 17), growth hormone deficiency (GHD; n = 35), Turner syndrome (TS; n = 27), short stature after being born small for gestational age (SGA; n = 20) and Klinefelter syndrome (KS; n = 11). Female and male adolescents exhibited mature secondary sexual characteristics. The levels of serum inhibin B and AMH were lower in TS and female MPHD than in GHD and SGA, each independently (p < 0.05). The levels of serum AMH were higher whereas serum inhibin B were lower in male MPHD and KS (p < 0.05). Ovary volumes were significantly smaller in patients with TS, and testicular volumes were smaller in patients with KS. CONCLUSIONS: After current established treatments with sex steroids, the development of secondary sexual characteristics was mature. However, impaired markers of fertility have been identified in patients with TS, KS and MPHD, reflecting gonadal dysgenesis in TS and KS, but gonadal immaturity in MPHD as gonadal gonadotropin stimulation is lacking throughout development. Consequently, in patients with MPHD, these markers cannot reliably predict individual fertility, which warrants consideration and incorporation in future treatment concepts.

Longitudinal assessment of bone health index as a measure of bone health in short-statured children before and during treatment with recombinant growth hormone.

OBJECTIVES: The aim of our study was the longitudinal assessment of bone health index (BHI) in short-statured children during growth hormone (GH) treatment to estimate changes in their bone health. METHODS: 256 short-statured children (isolated GH deficiency (IGHD) n=121, multiple pituitary hormone deficiency (MPHD) n=49, intrauterine growth retardation (small for gestational age (SGA)) n=52, SHOX (short stature homeobox gene) deficiency n=9, Ullrich Turner syndrome (UTS) n=25) who started with GH between 2010 and 2018 were included. Annual bone ages (Greulich and Pyle, GP) and BHI were, retrospectively, analysed in consecutive radiographs of the left hand (BoneXpert software) from GH therapy start (T0) up to 10 years (T10) thereafter, with T max indicating the individual time point of the last available radiograph. The results are presented as the median (25 %/75 % interquartile ranges, IQR) and statistical analyses were performed using non-parametric tests as appropriate. RESULTS: The BHI standard deviation scores (SDS) were reduced (-0.97, -1.8/-0.3) as bone ages were retarded (-1.6 years, -2.31/-0.97) in all patients before start of GH and were significantly lower in patients with growth hormone deficiency (GHD) (-1.04, -1.85/-0.56; n=170) compared to non-GHD patients (-0.79, -1.56/-0.01; n=86; p=0.022). BHI SDS increased to -0.17 (-1/0.58) after 1 year of GH (T1, 0.5-1.49, p<0.001) and to -0.20 (-1/-0.50, p<0.001) after 5.3 years (T max, 3.45/7.25). CONCLUSIONS: BHI SDS are reduced in treatment-naive short-statured children regardless of their GH status, increase initially with GH treatment while plateauing thereafter, suggesting sustained improved bone health.

A reverse genetics and genomics approach to gene paralog function and disease: Myokymia and the juxtaparanode.

The leucine-rich glioma-inactivated (LGI) family consists of four highly conserved paralogous genes, LGI1-4, that are highly expressed in mammalian central and/or peripheral nervous systems. LGI1 antibodies are detected in subjects with autoimmune limbic encephalitis and peripheral nerve hyperexcitability syndromes (PNHSs) such as Isaacs and Morvan syndromes. Pathogenic variations of LGI1 and LGI4 are associated with neurological disorders as disease traits including familial temporal lobe epilepsy and neurogenic arthrogryposis multiplex congenita 1 with myelin defects, respectively. No human disease has been reported associated with either LGI2 or LGI3. We implemented exome sequencing and family-based genomics to identify individuals with deleterious variants in LGI3 and utilized GeneMatcher to connect practitioners and researchers worldwide to investigate the clinical and electrophysiological phenotype in affected subjects. We also generated Lgi3-null mice and performed peripheral nerve dissection and immunohistochemistry to examine the juxtaparanode LGI3 microarchitecture. As a result, we identified 16 individuals from eight unrelated families with loss-of-function (LoF) bi-allelic variants in LGI3. Deep phenotypic characterization showed LGI3 LoF causes a potentially clinically recognizable PNHS trait characterized by global developmental delay, intellectual disability, distal deformities with diminished reflexes, visible facial myokymia, and distinctive electromyographic features suggestive of motor nerve instability. Lgi3-null mice showed reduced and mis-localized Kv1 channel complexes in myelinated peripheral axons. Our data demonstrate bi-allelic LoF variants in LGI3 cause a clinically distinguishable disease trait of PNHS, most likely caused by disturbed Kv1 channel distribution in the absence of LGI3.

Sex chromosome DSD individuals with mosaic 45,X0 and aberrant Y chromosomes in 46,XY cells: distinct gender phenotypes and germ cell tumour risks§.

"Differences of Sexual Development (DSD)," individuals with rearranged Y chromosome breaks in their 46,XY cells are reported with male and female gender phenotypes and differences in germ cell tumour (GCT) risk. This raised the question of whether male or female gender and GCT risk depends on the site of the break and/or rearrangement of the individual´s Y chromosome. In this paper, we report molecular mapping of the breakpoint on the aberrant Y chromosome of 22 DSD individuals with a 45,X/46,XY karyotype reared with a different gender. Their Y chromosome breaks are found at different sites on the long and short Y arms. Our data indicate that gender rearing is, neither dependent on the site of Y breakage, nor on the amount of 45,X0 cells in the individuals' leukocytes. Most prominent are secondary rearrangements of the Y chromosome breaks forming di-centric Y-structures ("dic-Y"). Duplications of the short Y arm and the proximal part of the long Y arm are the results. A putative GCT risk has been analysed with immunohistochemical experiments on some dysgenetic gonadal tissue sections. With specific antibodies for OCT3/4 expression, we marked the pluripotent germ cell fraction being potential tumour precursor cells. With specific antibodies for DDX3Y, TSPY, and UTY we analyzed their putative Gonadoblastoma Y (GBY) tumour susceptibility function in the same specimen. We conclude GBY expression is only diagnostic for GCT development in the aberrant germ cells of these DSD individuals when strong OCT3/4 expression has marked their pluripotency.

Clonal hematopoiesis as a pitfall in germline variant interpretation in the context of Mendelian disorders.

Clonal hematopoiesis because of somatic mutations in hematopoietic stem/progenitor cells is an age-related phenomenon and commonly observed when sequencing blood DNA in elderly individuals. Several genes that are implicated in clonal hematopoiesis are also associated with Mendelian disorders when mutated in the germline, potentially leading to variant misinterpretation. We performed a literature search to identify genes associated with age-related clonal hematopoiesis followed by an OMIM query to identify the subset of genes in which germline variants are associated with Mendelian disorders. We retrospectively screened for diagnostic cases in which the presence of age-related clonal hematopoiesis confounded exome sequencing data interpretation. We found 58 genes in which somatic mutations are implicated in clonal hematopoiesis, while germline variants in the same genes are associated with Mendelian (mostly neurodevelopmental) disorders. Using five selected cases of individuals with suspected monogenic disorders, we illustrate how clonal hematopoiesis in either variant databases or exome sequencing datasets poses a pitfall, potentially leading to variant misclassification and erroneous conclusions regarding gene-disease associations.

Typical characteristics of children with congenital adrenal hyperplasia due to 11ß-hydroxylase deficiency: a single-centre experience and review of the literature.

Background 11ß-hydroxylase deficiency (11ßOHD) is a rare disease representing the second most common cause of congenital adrenal hyperplasia (CAH) (5-8%) with an incidence of about 1:100,000. In contrast to 21-hydroxylase deficiency (21OHD), 11ßOHD is not included in neonatal screening programmes. The objective of this study was to demonstrate the typical features of male patients with 11ßOHD. Methods Clinical, biochemical and radiological data of patients with 11ßOHD were analysed in this retrospective single-centre analysis. Results Six male patients of four unrelated families with 11ßOHD were identified (0.1-13.5 years of chronological age [CA] at diagnosis). The predominant symptoms were arterial hypertension, tall stature and precocious pseudopuberty. Bone ages (BAs) were remarkably advanced at diagnosis in four index patients (median difference BA-CA: 5.5 years, range 1.5-9.2 years). Homozygous mutations were identified in exon 7 (c.1179_1180dupGA [p.Asn394Argfs*37]) and exon 8 (c.1398+2T>C) of the CYP11B1 gene leading both to a complete loss of function. The latter mutation has not yet been described in databases. 11ßOHD was identified by the measurement of 11-deoxycortisol in a newborn screening card of one patient retrospectively. Testicular adrenal rest tumours (TARTs) were detected in three patients at 3.7 years, 11 years and 14.4 years. Conclusion The diagnosis of CAH due to 11ßOHD is delayed and should be suspected in children with arterial hypertension, tall stature and precocious pseudopuberty. Patients may develop TARTs as early as infancy. 11ßOHD should be included in newborn screening programmes, at least in newborns of index families, to allow early diagnosis and the start of treatment to reduce morbidity.

Clinical Features and Response to Treatment of Prolactinomas in Children and Adolescents: A Retrospective Single-Centre Analysis and Review of the Literature.

BACKGROUND: Paediatric prolactinomas are rare. The aim of this study was to investigate the clinical features and outcome of paediatric patients with prolactinomas. METHODS: In this single-centre retrospective analysis, clinical, biochemical, and radiological features of all paediatric patients with pituitary adenomas diagnosed between 2000 and 2016 were evaluated. RESULTS: Among 21 patients with pituitary adenomas, 12 patients with prolactinomas (median age 14.2 years, range 11-16.6 years, 8 females, 4 males) were identified (7 macro- and 5 microprolactinomas). The most common clinical symptoms were headaches (67%) and pubertal delay (67%). All patients with macroprolactinomas with prolactin concentrations >10,000 mU/L had at least 1 pituitary hormone deficiency. Cabergoline as first-line treatment (n = 11, median follow-up of 37 months, range 12-89 months) induced normoprolactinemia (n = 8), reduced the mean tumour volume by 80%, and ameliorated headaches (p = 0.016) and pubertal delay (p = 0.031), whereas intermittent moderate side effects occurred in 55%. CONCLUSION: Adolescents with headaches and pubertal delay should be investigated for prolactinomas. Treatment with cabergoline is well tolerated and effective in reducing clinical symptoms and prolactin concentrations was well as inducing tumour shrinkage. Further clinical prospective studies are needed to standardize paediatric treatment modalities.

Identification of SLC20A1 and SLC15A4 among other genes as potential risk factors for combined pituitary hormone deficiency.

PURPOSE: Combined pituitary hormone deficiency (CPHD) is characterized by a malformed or underdeveloped pituitary gland resulting in an impaired pituitary hormone secretion. Several transcription factors have been described in its etiology, but defects in known genes account for only a small proportion of cases. METHODS: To identify novel genetic causes for congenital hypopituitarism, we performed exome-sequencing studies on 10 patients with CPHD and their unaffected parents. Two candidate genes were sequenced in further 200 patients. Genotype data of known hypopituitary genes are reviewed. RESULTS: We discovered 51 likely damaging variants in 38 genes; 12 of the 51 variants represent de novo events (24%); 11 of the 38 genes (29%) were present in the E12.5/E14.5 pituitary transcriptome. Targeted sequencing of two candidate genes, SLC20A1 and SLC15A4, of the solute carrier membrane transport protein family in 200 additional patients demonstrated two further variants predicted as damaging. We also found combinations of de novo (SLC20A1/SLC15A4) and transmitted variants (GLI2/LHX3) in the same individuals, leading to the full-blown CPHD phenotype. CONCLUSION: These data expand the pituitary target genes repertoire for diagnostics and further functional studies. Exome sequencing has identified a combination of rare variants in different genes that might explain incomplete penetrance in CPHD.

Long-Term Neurodevelopmental Outcome of Children Treated with Tri-Iodothyronine after Cardiac Surgery: Follow-Up of a Double-Blind, Randomized, Placebo-Controlled Study.

BACKGROUND: Transient thyroid dysfunction occurs in children after cardiopulmonary bypass (CPB). We demonstrated significant benefits of acute postoperative tri-iodothyronine (T3) treatment for recovery and myocardial function. Now we report the long-term neurodevelopment of these children. METHODS: Twenty-eight children (70% of the original study population) could be recruited for a follow-up examination (median age 10.7 years, range 10-19.6 years) retaining the double-blind, randomized, placebo-controlled protocol. Cognitive function and motor development were tested, as were growth and thyroid and cardiac functions. RESULTS: The median full-scale intelligence quotient of all children was within the reference range and similar in the placebo and T3 groups. Tests for motor and cognitive functions, growth, and thyroid and cardiac functions revealed concurrent results. CONCLUSIONS: Overall intellectual development is preserved in adolescents treated with CPB in infancy irrespectively of low postoperative thyroid hormone concentrations. While acute postoperative T3 treatment in children after CPB improves recovery, no significant long-term effects on neurodevelopment could be detected. We therefore speculate that transient postoperative thyroid dysfunction by means of nonthyroidal illness syndrome is predominantly mediated by extranuclear, nongenomic mechanisms and thus acutely affects the cardiovascular system but not the development of the central nervous system mediated by genomic mechanisms.

Inhibition of IGF-I-related intracellular signaling pathways by proinflammatory cytokines in growth plate chondrocytes.

BACKGROUND: Children with chronic inflammatory diseases suffer from severe growth failure associated with resistance toward the anabolic action of insulin-like growth factor I (IGF-I). We hypothesized that proinflammatory cytokines interfere with IGF-I signaling. METHODS: We used the mesenchymal chondrogenic cell line RCJ3.1C5.18 as a model of the growth plate. Cell proliferation was assessed by [(3)H]-thymidine-uptake and differentiation by gene expression (quantitative reverse-transcriptase PCR) of specific differentiation markers. Key signaling molecules of the respective IGF-I-related intracellular pathways were determined by western immunoblotting. RESULTS: Coincubation of the proinflammatory cytokines interleukin (IL)-1ß (10 ng/ml), IL-6 (100 ng/ml), or tumor necrosis factor-α (50 ng/ml) with IGF-I inhibited IGF-I-driven cell proliferation by 50%, while baseline cell proliferation was not altered. These cytokines attenuated the IGF-I-induced phosphorylation of AKT as a key signaling molecule of the phosphatidylinositol-3 kinase pathway by 30-50% and the phosphorylation of ERK as a key signaling molecule of the mitogen-activated protein kinase/extracellular signal-regulated kinase pathway by 50-75%. Also, IGF-I-enhanced chondrocyte differentiation was inhibited by these proinflammatory cytokines. CONCLUSION: The insensitivity toward the anabolic action of IGF-I in the growth plate in conditions of chronic inflammation is partially due to inhibition of IGF-I-specific signaling pathways by proinflammatory cytokines, which affect both IGF-I-driven chondrocyte proliferation and differentiation.

Virilization of a young girl caused by concomitant ectopic and intra-adrenal adenomas of the adrenal cortex.

BACKGROUND: Adenomas of the adrenal gland are rare causes of virilization in childhood. CASE REPORT: A girl aged 2 years and 4 months presented with pubarche, distinct clitoral hypertrophy, tall stature, and increased height velocity. Plasma testosterone and dehydroepiandrosterone were elevated. Androgens remained unchanged after adrenocorticotropic hormone, and dexamethasone administrations. Ultrasound examination and magnetic resonance imaging indicated an extra-adrenal mass adjacent to the left adrenal gland, which was removed by endoscopic surgery. However, plasma androgens remained elevated and (131)I-iodomethyl-norcholesterol scintigraphy revealed tracer enhancement in the right adrenal gland, which was consecutively removed. Virilization regressed after extirpation of the adenomas and height velocity normalized. RESULTS: Histology revealed a circumscribed adenoma in the right adrenal gland and an epithelial mass with adrenal cortical cells in the left-sided ectopic tumor. In the ectopic tumor, melanocortin 2 receptor expression was augmented threefold compared to the control, indicating adrenal origin. CONCLUSIONS: In this young girl, virilization is due to concomitant ectopic and intra-adrenal adenomas of the adrenal cortex. By melanocortin 2 receptor expression, it was confirmed that the ectopic adenoma derived from the adrenal cortex. Specific scintigraphy, if available, assists in allocating the source of androgen hypersecretion.