Epidemiology of Tumor-Induced Osteomalacia in Germany Based on Real World Data.

Tumor-induced osteomalacia (TIO) is an ultra-rare disease caused mostly by benign tumors that secrete fibroblast growth factor-23. Because of nonspecific symptoms, the diagnostic delay is long, and therapy can be challenging. Moreover, epidemiological data on TIO are scarce owing to its rarity. Therefore, this study aimed to quantify TIO's incidence rates and prevalence in Germany. Retrospective longitudinal and cross-sectional analyses were conducted using anonymized German claims data from the statutory health insurance (SHI) database. This database, which comprises the data of approximately 5 million insurants, is a representative sample of the German population and supports national projections. As there is no unique International Statistical Classification of Diseases and Related Health Problems (ICD) code for TIO, operational categories based on different surrogates were defined to determine the prevalence and incidence rates of TIO among probable patients. This study showed that TIO has a prevalence of (documented code, advanced imaging, medication, or tumor removal) 0.187 per 100,000 persons and an incidence rate of ≤ 0.094 per 100,000 person years. This analysis provides the first epidemiological insight into German patients with TIO. Despite the general limitations associated with the analysis of SHI claims data of ultra-rare diseases, we believe that this analysis provides a sound basis for further analysis, particularly with regard to the care situation of patients with TIO.

Epidemiology of mature T/NK-cell lymphomas in Germany - A representative cross-sectional study based on SHI claims data.

BACKGROUND: Primary cutaneous lymphomas (PCL) are rare skin tumors of lymphoproliferative neoplasms and belong to the heterogeneous group of non-Hodgkin's lymphomas. PCL encompass a broad spectrum of clinical and histologic manifestations, with cutaneous T-cell lymphoma (CTCL) being the most common (73%). Due to the rarity of the diseases, population-based studies of care and epidemiology are limited. PATIENTS AND METHODS: Based on anonymized, age- and sex-adjusted SHI (statutory health insurance) claims data of approximately five million SHI-insured patients, a retrospective analysis was conducted over a six-year period (2012-2017) to determine the prevalence, incidence, and lethality in patients with mature-cell T/NK-cell lymphoma in Germany. RESULTS: A total of 1,336 patients with T-cell lymphoma were identified during the observation period. The six-year prevalence ranged from 27.35 to 43.58 per 100,000. Patients were 65% male with a mean age of 66 years (SD 15). There were 246 patients (approx. 20%) who died within the 6 years, up to 7% per year. The calculated incidence in 153 identified patients in 2017 is 3.65 to 3.92 per 100,000. CONCLUSIONS: For the first time, valid epidemiologic findings of patients with mature T-cell and NK-cell lymphomas were obtained using SHI claims data in Germany. Further analyses are needed to gain a deeper insight into the healthcare reality of patients with this rare disease.

Sleep disturbances in Phelan-McDermid syndrome: Clinical and metabolic profiling of 56 individuals.

Phelan-McDermid Syndrome (PMS) is caused by deletions at chromosome 22q13.3 or pathogenic/likely pathogenic SHANK3 variants. The clinical presentation is extremely variable and includes global developmental delay/intellectual disability (ID), seizures, neonatal hypotonia, and sleep disturbances, among others. This study investigated the prevalence of sleep disturbances, and the genetic and metabolic features associated with them, in a cohort of 56 individuals with PMS. Sleep data were collected via standardized observer/caregiver questionnaires, while genetic data from array-CGH and sequencing of 9 candidate genes within the 22q13.3 region, and metabolic profiling utilized the Biolog Phenotype Mammalian MicroArray plates. Sleep disturbances were present in 64.3% of individuals with PMS, with the most common problem being waking during the night (39%). Sleep disturbances were more prevalent in individuals with a SHANK3 pathogenic variant (89%) compared to subjects with 22q13.3 deletions of any size (59.6%). Distinct metabolic profiles for individuals with PMS with and without sleep disturbances were also identified. These data are helpful information for recognizing and managing sleep disturbances in individuals with PMS, outlining the main candidate gene for this neurological manifestation, and highlighting potential biomarkers for early identification of at-risk subjects and molecular targets for novel treatment approaches.

Care reality of menopausal women in Germany: healthcare research using quantitative (SHI claims data) and qualitative (survey) data collection.

PURPOSE: The transition from the fertile phase of life to menopause is associated with numerous physical changes. Hormone replacement therapy (HRT), as the most effective and efficient form of drug treatment, involves the use of oestrogens and progestins with the aim of increasing health-related quality of life through symptom reduction, sleep improvement and affect enhancement. METHODS: The medical care situation and disease burden of menopausal women was investigated by means of a survey of 1000 women aged 45-60 years on the topics of quality of life, menopause and HRT and a quantitative, longitudinal healthcare study based on an anonymised and age- and sex-adjusted Statutory Health Insurance (SHI) routine data set with approximately four million anonymous insured persons per year. RESULTS: Out of more than half a million women aged 35-70 years, and with statutory health insurance, (n = 613,104), 14% (n = 82,785) had climacteric disorder documented as a first diagnosis in 2014. The proportion of women with the climacteric disorder, who were prescribed HRT on an outpatient basis, was 21%; according to the forsa survey, 50% of the women surveyed felt moderate to poorly/very poorly informed about treatment options. CONCLUSION: Findings from the health insurance research conducted with different data sources (survey and SHI claims data) indicate the need for increasing awareness and providing an early and informative education on HRT and its risks and benefits.

Genetic and metabolic profiling of individuals with Phelan-McDermid syndrome presenting with seizures.

Phelan-McDermid syndrome (PMS) (OMIM*606232) is a rare genetic disorder characterized by intellectual disability, autistic features, speech delay, minor dysmorphia, and seizures. This study was conducted to investigate the prevalence of seizures and the association with genetic and metabolic features since there has been little research related to seizures in PMS. For 57 individuals, seizure data was collected from caregiver interviews, genetic data from existing cytogenetic records and Sanger sequencing for nine 22q13 genes, and metabolic profiling from the Phenotype Mammalian MicroArray (PM-M) developed by Biolog. Results showed that 46% of individuals had seizures with the most common type being absence and grand-mal seizures. Seizures were most prevalent in individuals with pathogenic SHANK3 mutations (70%), those with deletion sizes >4 Mb (16%), and those with deletion sizes <4 Mb (71%) suggesting involvement of genes in addition to SHANK3. Additionally, a 3 Mb genomic region on 22q13.31 containing the gene TBC1D22A, was found to be significantly associated with seizure prevalence. A distinct metabolic profile was identified for individuals with PMS with seizures and suggested among other features a disrupted utilization of main energy sources using Biolog plates. The results of this study will be helpful for clinicians and families in anticipating seizures in these children and for researchers to identify candidate genes for the seizure phenotype.

Anticoagulation Therapy in Cancer Patients with Thrombosis in the Outpatient Sector of Germany (The CERTIFICAT Initiative)-German Practice of Anticoagulation Therapy of Cancer Patients with Thrombosis.

OBJECTIVE: This article aims to investigate the reality of anticoagulation treatment for cancer patients with thrombosis in the outpatient sector of Germany. METHODS: For the analysis period 2012 to 2015, anonymized data from 4.1 million statutory insured patients were analyzed. Cancer patients with incident thrombosis and an outpatient prescription of anticoagulant drugs were identified and evaluated for three subsequent quarters with regard to anticoagulant use. RESULTS: A total of 7,313 cancer patients with incident thrombosis (ICD-10: I80*) were evaluated. About, 90% of patients with thromboses were diagnosed and treated in the ambulatory sector. More than 80% of the prescriptions were issued by general practitioners. And 57% of patients were anticoagulated predominantly (>50% of the time) with different low-molecular-weight heparins (LMWHs), 24% predominantly with vitamin K antagonists (VKAs), and 17% with direct oral anticoagulants (DOACs). Anticoagulants were prescribed for an average of 4.5 months. LMWH had a substantially longer prescription period (90-135 days) than VKA (53 days) or DOAC (47 days). Gastrointestinal bleeding in conjunction with hospitalization was documented in 1.76% of patients with a range of 1.3 to 3% for the different LMWHs. CONCLUSION: The prescription practice documented by this representative and comprehensive evaluation demonstrates an anticoagulation duration in accordance with the guidelines, although the choice of the respective anticoagulant was often not in compliance with the contemporary label or guidelines.

Spinal cord stimulation: a real-world data analysis on outcomes and differences between rechargeable and non-rechargeable implantable pulse generators.

OBJECTIVE: In this analysis, we examined differences between rechargeable and non-rechargeable spinal cord stimulation (SCS) devices in patients with pain. METHODS: We conducted a retrospective, longitudinal claims data analysis using a German research database comprising 5 million statutory insured patients (2012-2017). Outcomes of demographics, patient pathways, and health care resource utilization (HCRU) in patients with initial SCS were collected. RESULTS: Of 150 patients in the database, 73 (49%) received a rechargeable device and 77 (51%) a non-rechargeable device. The average age was 62.5 years (51% female and 49% male patients). A significant decrease over a 3-year follow-up was observed in analgesic prescriptions (-18%), number of patient visits to a physician, and number of patients who were hospitalized. HCRU-related figures for patients with non-rechargeable neurostimulators increased in the last follow-up year whereas the group receiving rechargeable neurostimulators showed a steady decrease. CONCLUSIONS: SCS seems to be an effective way for patients with chronic pain to decrease pain and improve quality of life. Rechargeable devices seem to be superior to non-rechargeable devices owing to greater longevity and were found to be associated with continuous reduction of pain diagnoses, hospitalization, physician visits, and use of pain medication in our study.

Real-world data and treatment patterns of patients with lower urinary tract symptoms due to benign prostatic hyperplasia in Germany: an observational study using health insurance claims data.

PURPOSE: Benign prostatic hyperplasia (BPH) is associated with lower urinary tract symptoms (LUTS), representing one of the most common urological conditions. However, insights into the actual healthcare of this patient cohort in Germany are scarce. We aimed to retrospectively analyse management patterns of patients with LUTS in Germany using health insurance claims databases. METHODS: A retrospective, longitudinal cohort analysis was conducted obtaining claims data from the German InGef health insurance database containing approximately five million member-records from over 60 nationwide statutory health insurances. First, a cross-sectional prevalence analysis was performed on all individuals with a diagnosis on LUTS (ICD-10 GM N40) in 2018. Second, a longitudinal analysis of individuals with either a newly started BPH medication or initial BPH surgery who were indexed in 2014 and followed-up for 4 years. RESULTS: In 2018, 132,386 (6.7%) prevalent BPH patients were identified from 1,979,916 continuously insured males. A potential overcoding bias could not be assessed which may influence the outpatient sector estimation. 10,361 (0.7%) patients were identified with incident BPH medication and 1768 (0.1%) patients with incident BPH surgery out of 1,575,604 males (2013-2018). Alpha-blockers were the drug of choice (95.6%) in the first year. Half of patients received specific BPH medications four years after index, while almost 98% of initial BPH surgeries were performed within the inpatient setting. TURP was the most frequent surgical intervention (76%). CONCLUSIONS: A widespread diffusion of alternative individualized minimally invasive approaches in the outpatient sector might address pharmacotherapy discontinuation and patient-access barriers to other treatments.

Severe multisystem pathology, metabolic acidosis, mitochondrial dysfunction, and early death associated with an X-linked AIFM1 variant.

Variants in the X-linked gene AIFM1 (apoptosis-inducing factor mitochondria-associated 1) are associated with a highly variable clinical presentation that encompasses motor neuropathy, ataxia, encephalopathies, deafness, and cognitive impairment. AIFM1 encodes a mitochondrial flavin adenine dinucleotide (FAD)-dependent nicotinamide adenine dinucleotide (NADH) oxidoreductase, with roles in the regulation of respiratory complex assembly and function, production of reactive oxygen species, and the coordination of a caspase-independent type of apoptosis known as parthanatos. In this report, we describe a missense AIFM1 variant (absent in reference population databases; c.506C > T, p.Pro169Leu) identified in the proband and sibling of a family with three affected males. The proband, his brother, and their maternal uncle all exhibited severe multisystem pathology, metabolic acidosis, and early demise. Metabolic testing on the proband revealed normal activity of the pyruvate dehydrogenase complex in skin fibroblasts. Absent or partial deficiency of cytochrome c oxidase was found in muscle fibers, however, supporting a Complex IV mitochondrial deficiency. Functional studies carried out on fibroblasts from the proband demonstrated reduced steady state levels of the AIFM1 protein, decreased Complex I subunit abundance, elevated sensitivity to the apoptosis inducer staurosporine, and increased nuclear condensation when grown in galactose-containing media. The reduced abundance of AIFM1 in the patient cells could not be stabilized with riboflavin or protease inhibitor treatment. Together, these findings suggest that the normal function of the AIFM1 gene product within mitochondria, and its response to apoptotic stimuli, are impaired by this variant, likely accounting for the severity of the phenotype seen in these patients. These findings also imply tissue-specific effects of this variant on different mitochondrial complexes. This study expands the genetic and phenotypic spectrum associated with AIFM1 variants, with the combination of exome sequencing and functional studies allowing a diagnosis to finally be confirmed for this family.

Persistence With Biologic Therapy and Associated Costs of Patients With Inflammatory Bowel Disease: A German Retrospective Claims Data Analysis.

Background: In recent years, biologic agents became a relevant and promising treatment option for inflammatory bowel diseases (IBDs). However, high treatment costs and moderate remission rates lead to a high interest in treatment persistence and corresponding economic consequences. Methods: A retrospective health claims data analysis was conducted including biologic naive patients diagnosed with IBD between 2013 and 2018. Observation points were at 12 and 18 months of follow-up, starting from the first biologic prescription. Nonpersistence was defined as either no further prescription or prescription of another biologic agent within the days of supply per original prescription. Biologic agents included were Adalimumab, Golimumab, Infliximab, Ustekinumab, and Vedolizumab. Results: In total, 1444 patients with IBD were included in this analysis, mostly treated with Adalimumab (46.9%) and Infliximab (39.9%) as their first biologic treatment. After 12 months, 72.2% of patients were still persistent with their initial biologic treatment with the highest shares for Infliximab (74%) and Vedolizumab (72.4%). 27.8% of patients were nonpersistent, mostly due to a switch of biologic agent (75.8%). Cox regression identified female, hospitalizations, and simultaneous prescriptions of corticosteroids and immunomodulators as risk factors for nonpersistence. Treatment costs per year were approximately 3000€ higher for nonpersistent patients (27,146€) than for persistent patients (23,839€), mostly due to inpatient treatment costs. Conclusions: The persistence of biologic therapy in this study was rather high at 72% after 12 months, while nonpersistence was mostly due to switches to other biologic agents. Lack of persistence is associated with increased cost, mostly due to nonbiologic medication and inpatient treatment.

Disease burden and direct medical costs of incident adult ADHD: A retrospective longitudinal analysis based on German statutory health insurance claims data.

BACKGROUND: Adult attention-deficit/hyperactivity disorder (aADHD) is still a largely unrecognized psychiatric condition despite its strong impact on individuals' well-being. Here, we describe the healthcare situation of individuals with incident aADHD over 4 years before and 4 years after initial administrative diagnosis. METHODS: A retrospective, longitudinal cohort analysis was conducted using German claims data. The InGef database contained approximately 5 million member-records from over 60 nationwide statutory health insurances (SHI). Individuals were indexed upon initial diagnosis of aADHD. RESULTS: Average age at diagnosis of aADHD was 35 years, and 60% of individuals were male. Comorbidities, resource use, and healthcare costs were substantial before initial diagnosis and decreased within the 4 years thereafter. Only 32% of individuals received initial ADHD medication and adherence was low. The majority received psychotherapy. Individuals with initial ADHD medication showed the highest share in comorbidities, physician visits, medication use for comorbidities, psychotherapy, and costs. Overall, healthcare costs were at over €4,000 per individual within the year of aADHD diagnosis. CONCLUSIONS: We conclude that earlier recognition of aADHD could prevent the development and aggravation of comorbid mental illnesses. At the same time, comorbid conditions may have masked ("over-shadowed") aADHD and delayed diagnosis. The burden of disease in aADHD is high, which was noticeable especially among individuals who received initial ADHD-medication, suggesting that psychopharmacological treatment was mainly considered for the most severely ill. We conclude that measures to facilitate access of aADHD patients to clinical experts are required to improve reality of care in the outpatient setting.

De Novo Variants in LMNB1 Cause Pronounced Syndromic Microcephaly and Disruption of Nuclear Envelope Integrity.

Lamin B1 plays an important role in the nuclear envelope stability, the regulation of gene expression, and neural development. Duplication of LMNB1, or missense mutations increasing LMNB1 expression, are associated with autosomal-dominant leukodystrophy. On the basis of its role in neurogenesis, it has been postulated that LMNB1 variants could cause microcephaly. Here, we confirm this hypothesis with the identification of de novo mutations in LMNB1 in seven individuals with pronounced primary microcephaly (ranging from -3.6 to -12 SD) associated with relative short stature and variable degree of intellectual disability and neurological features as the core symptoms. Simplified gyral pattern of the cortex and abnormal corpus callosum were noted on MRI of three individuals, and these individuals also presented with a more severe phenotype. Functional analysis of the three missense mutations showed impaired formation of the LMNB1 nuclear lamina. The two variants located within the head group of LMNB1 result in a decrease in the nuclear localization of the protein and an increase in misshapen nuclei. We further demonstrate that another mutation, located in the coil region, leads to increased frequency of condensed nuclei and lower steady-state levels of lamin B1 in proband lymphoblasts. Our findings collectively indicate that de novo mutations in LMNB1 result in a dominant and damaging effect on nuclear envelope formation that correlates with microcephaly in humans. This adds LMNB1 to the growing list of genes implicated in severe autosomal-dominant microcephaly and broadens the phenotypic spectrum of the laminopathies.

Correction to: Imaging Intensity and Survival Outcomes in High-Risk Resected Melanoma Treated by Systemic Therapy at Recurrence.

In the original article, the survival curves are missing in Fig. 1c, d.

Imaging Intensity and Survival Outcomes in High-Risk Resected Melanoma Treated by Systemic Therapy at Recurrence.

BACKGROUND: Intensive imaging in melanoma remains controversial because its survival impact is unknown. We investigated the impact of imaging intensity on the rates of asymptomatic surveillance-detected recurrence (ASDR) and subsequent treatment outcomes in patients with access to immune checkpoint inhibitors (ICIs) and targeted therapy (TT). METHODS: Patients with resected malignant melanoma undergoing imaging surveillance at a single center between 2006 and 2016 were identified. Surveillance and recurrence characteristics (imaging, symptom, treatment, and survival data) were retrospectively collected. Univariate (t test, Chi square test) and multivariate Cox regression analyses were conducted. RESULTS: Of 353 high-risk melanoma patients (stage IIB, 24%; IIC, 19%; IIIA, 27%; IIIB, 16%; IIIC, 14%), 71 (45%) had ASDR and 88 (55%) had symptomatic recurrence (SR). Shorter imaging intervals identified more ASDR (57%, 0-6 months; 34%, 6-12 months; 33%, > 12 months; p = 0.03). ASDR had better prognostic factors than SR [fewer than three metastatic sites (43 vs. 21%, p = 0.003), normal lactate dehydrogenase (LDH; 53 vs. 38%, p = 0.09), brain metastases (11 vs. 40%, p < 0.001)] and received more systemic treatment (72 vs. 49%, p = 0.003; ICIs 55 vs. 31%, p = 0.002; TT 8 vs. 13%, p = 0.41). ASDR had better survival outcomes on ICI treatment (2-year OS, 56 vs. 31%, p < 0.001). Median OS from surveillance start was 39.6 vs. 22.8 months (p < 0.001). ASDR was independently associated with survival (hazard ratio 0.47, 95% confidence interval 0.29-0.78, p = 0.003), adjusting for stage, sex, age, disease burden, LDH, era of recurrence, brain metastases, and ICI/TT treatment. CONCLUSIONS: These real-world data support further study on intensified imaging surveillance protocols for high-risk resected melanoma, as ASDR was associated with superior survival outcomes from ICI therapy.

Living with ulcerative colitis in Germany: a retrospective analysis of dose escalation, concomitant treatment use and healthcare costs.

Aims: To investigate treatment of moderate-to-severe ulcerative colitis (UC) using real-world German health insurance claims data.Materials and methods: A retrospective, longitudinal cohort study was conducted from a German statutory health insurance database for adult patients with UC indexed on biologic therapy initiation (2013-2015). Anonymized data were evaluated for 12 months prior to (baseline) through 24 months after (follow-up) indexing. Biologic dose escalations, steroid and immunosuppressant use, healthcare resource utilization (HCRU) and direct healthcare costs were evaluated, with significant differences assessed across and between index biologics. Descriptive statistics, chi-square or Fisher's exact tests, and analysis of variance were performed.Results: The analysis included 304 patients (adalimumab, n = 125; golimumab, n = 47; infliximab, n = 114; vedolizumab, n = 18). Demographic and clinical characteristics were similar across biologics. Dose escalations occurred in 58% of patients (73% of patients receiving adalimumab), with 41% receiving subsequent de-escalation. Steroids were used during follow-up by 74% of patients; 25% received steroids >14 weeks after indexing. Overall, 41% of patients received an immunosuppressant during follow-up. Steroid and immunosuppressant use were similar across biologics. Total direct healthcare costs were higher during follow-up than baseline and differed significantly across treatments (p < .05), with highest costs for golimumab. Biologic costs contributed to a major portion of follow-up costs. HCRU and costs for most resources were higher in the first 12-month follow-up period than baseline. All resource use except gastroenterology visits returned to, or below, baseline levels 13-24 months post-index date.Limitations: There was potential for inappropriate inclusion/exclusion due to miscoding. Patients may have received biologics >12 months prior to the index date. Biologic originators and biosimilars could not be differentiated.Conclusions: These data suggest that control with current biologics is suboptimal. Further treatment options that provide sustained steroid-free remission for this patient population without the need for dose escalations or concomitant therapies may be warranted.

Outcome comparison of integrated psycho-oncological care versus unstructured care-Results of a non-randomised open-label two-arm trial.

OBJECTIVE: To compare patients' experiences with a systematic, integrated psycho-oncological care (IC) model to experiences with "care as usual" (CAU). METHODS: To improve patients' knowledge about psychosocial support options and to facilitate use, an IC model was developed by psycho-oncologists and a health insurance company and implemented in one German cancer care facility. Using a parallel, non-randomised design, these patients' experiences were compared to CAU patients. In 2015, both patient groups received questionnaires 6-12 months post-inpatient treatment. Main outcomes were awareness, use and opinion of psycho-oncological care (PC) and anxiety level (Generalized Anxiety Disorder Scale (GAD-7)). RESULTS: 228 patients (IC = 90; CAU = 138) participated (response rate 24%). More IC patients felt adequately informed about PC (63% vs. 46%, ORadj : 2.5 (CI: 1.3-4.8); p = 0.008). More IC patients recalled being offered various support options and had had at least one PC discussion (44% vs. 33%, ORadj of IC patient saying "yes" instead of "No, didn't want to" compared to a CAU patient: 0.4 (CI: 0.2-0.8); p = 0.01). More IC patients rated their care as good/excellent (49% vs. 38%, ORadj : 1.8 (CI: 0.7-4.1; p = 0.2)). Anxiety levels were similar (GAD-7 score>=10: IC 34% vs. CAU 28%; p = 0.4). CONCLUSION: Structured psycho-oncological care had some positive results on the outcomes, but anxiety levels did not differ.

Selective inhibition of N-linked glycosylation impairs receptor tyrosine kinase processing.

Global inhibition of N-linked glycosylation broadly reduces glycan occupancy on glycoproteins, but identifying how this inhibition functionally impacts specific glycoproteins is challenging. This limits our understanding of pathogenesis in the congenital disorders of glycosylation (CDG). We used selective exo-enzymatic labeling of cells deficient in the two catalytic subunits of oligosaccharyltransferase - STT3A and STT3B - to monitor the presence and glycosylation status of cell surface glycoproteins. We show reduced abundance of two canonical tyrosine receptor kinases - the insulin receptor and insulin-like growth factor 1 receptor (IGF-1R) - at the cell surface in STT3A-null cells, due to decreased N-linked glycan site occupancy and proteolytic processing in combination with increased endoplasmic reticulum localization. Providing cDNA for Golgi-resident proprotein convertase subtilisin/kexin type 5a (PCSK5a) and furin cDNA to wild-type and mutant cells produced under-glycosylated forms of PCSK5a, but not furin, in cells lacking STT3A. Reduced glycosylation of PCSK5a in STT3A-null cells or cells treated with the oligosaccharyltransferase inhibitor NGI-1 corresponded with failure to rescue receptor processing, implying that alterations in the glycosylation of this convertase have functional consequences. Collectively, our findings show that STT3A-dependent inhibition of N-linked glycosylation on receptor tyrosine kinases and their convertases combines to impair receptor processing and surface localization. These results provide new insight into CDG pathogenesis and highlight how the surface abundance of some glycoproteins can be dually impacted by abnormal glycosylation.

Dysregulations of sonic hedgehog signaling in MED12-related X-linked intellectual disability disorders.

BACKGROUND: Mutations in mediator of RNA polymerase II transcription subunit 12 homolog (MED12, OMIM 300188) cause X-linked intellectual disability (XLID) disorders including FG, Lujan, and Ohdo syndromes. The Gli3-dependent Sonic Hedgehog (SHH) signaling pathway has been implicated in the original FG syndrome and Lujan syndrome. How are SHH-signaling defects related to the complex clinical phenotype of MED12-associated XLID syndromes are not fully understood. METHODS: Quantitative RT-PCR was used to study expression levels of three SHH-signaling genes in lymophoblast cell lines carrying four MED12 mutations from four unrelated XLID families. Genotype and phenotype correlation studies were performed on these mutations. RESULTS: Three newly identified and one novel MED12 mutations in six affected males from four unrelated XLID families were studied. Three mutations (c.2692A>G; p.N898D, c.3640C>T; p.R1214C, and c.3884G>A; p.R1295H) are located in the LS domain and one (c.617G>A; p.R206Q) is in the L domain of MED12. These mutations involve highly conserved amino acid residues and segregate with ID and related congenital malformations in respective probands families. Patients with the LS-domain mutations share many features of FG syndrome and some features of Lujan syndrome. The patient with the L-domain mutation presented with ID and predominant neuropsychiatric features but little dysmorphic features of either FG or Lujan syndrome. Transcript levels of three Gli3-dependent SHH-signaling genes, CREB5, BMP4, and NEUROG2, were determined by quantitative RT-PCR and found to be significantly elevated in lymphoblasts from patients with three mutations in the MED12-LS domain. CONCLUSIONS: These results support a critical role of MED12 in regulating Gli3-dependent SHH signaling and in developing ID and related congenital malformations in XLID syndromes. Differences in the expression profile of SHH-signaling genes potentially contribute to variability in clinical phenotypes in patients with MED12-related XLID disorders.