Familial hypercholesterolaemia in children and adolescents from 48 countries: a cross-sectional study

BACKGROUND

Approximately 450 000 children are born with familial hypercholesterolaemia worldwide every year, yet only 2·1% of adults with familial hypercholesterolaemia were diagnosed before age 18 years via current diagnostic approaches, which are derived from observations in adults. We aimed to characterise children and adolescents with heterozygous familial hypercholesterolaemia (HeFH) and understand current approaches to the identification and management of familial hypercholesterolaemia to inform future public health strategies.

METHODS

For this cross-sectional study, we assessed children and adolescents younger than 18 years with a clinical or genetic diagnosis of HeFH at the time of entry into the Familial Hypercholesterolaemia Studies Collaboration (FHSC) registry between Oct 1, 2015, and Jan 31, 2021. Data in the registry were collected from 55 regional or national registries in 48 countries. Diagnoses relying on self-reported history of familial hypercholesterolaemia and suspected secondary hypercholesterolaemia were excluded from the registry; people with untreated LDL cholesterol (LDL-C) of at least 13·0 mmol/L were excluded from this study. Data were assessed overall and by WHO region, World Bank country income status, age, diagnostic criteria, and index-case status. The main outcome of this study was to assess current identification and management of children and adolescents with familial hypercholesterolaemia.

FINDINGS

Of 63 093 individuals in the FHSC registry, 11 848 (18·8%) were children or adolescents younger than 18 years with HeFH and were included in this study; 5756 (50·2%) of 11 476 included individuals were female and 5720 (49·8%) were male. Sex data were missing for 372 (3·1%) of 11 848 individuals. Median age at registry entry was 9·6 years (IQR 5·8-13·2). 10 099 (89·9%) of 11 235 included individuals had a final genetically confirmed diagnosis of familial hypercholesterolaemia and 1136 (10·1%) had a clinical diagnosis. Genetically confirmed diagnosis data or clinical diagnosis data were missing for 613 (5·2%) of 11 848 individuals. Genetic diagnosis was more common in children and adolescents from high-income countries (9427 [92·4%] of 10 202) than in children and adolescents from non-high-income countries (199 [48·0%] of 415). 3414 (31·6%) of 10 804 children or adolescents were index cases. Familial-hypercholesterolaemia-related physical signs, cardiovascular risk factors, and cardiovascular disease were uncommon, but were more common in non-high-income countries. 7557 (72·4%) of 10 428 included children or adolescents were not taking lipid-lowering medication (LLM) and had a median LDL-C of 5·00 mmol/L (IQR 4·05-6·08). Compared with genetic diagnosis, the use of unadapted clinical criteria intended for use in adults and reliant on more extreme phenotypes could result in 50-75% of children and adolescents with familial hypercholesterolaemia not being identified.

INTERPRETATION

Clinical characteristics observed in adults with familial hypercholesterolaemia are uncommon in children and adolescents with familial hypercholesterolaemia, hence detection in this age group relies on measurement of LDL-C and genetic confirmation. Where genetic testing is unavailable, increased availability and use of LDL-C measurements in the first few years of life could help reduce the current gap between prevalence and detection, enabling increased use of combination LLM to reach recommended LDL-C targets early in life.

FUNDING

Pfizer, Amgen, Merck Sharp & Dohme, Sanofi-Aventis, Daiichi Sankyo, and Regeneron.

Clinical significance of polymorphisms of genes encoding collagen (COL1A1, COL5A1) and their correlation with joint laxity and recurrent patellar dislocation in adolescents

The aim of this study was to assess the coexistence of polymorphisms of the COL1A1 and COL5A1 genes with clinically diagnosed laxity and the occurrence of recurrent patellar dislocation in adolescents. The research group comprised 50 cases of recurrent patellar dislocation. The mean age at diagnosis was 14.2 years (10-17, SD 2.6). The control group consisted of 199 participants without a diagnosis of recurrent patellar dislocation, with a mean age of 15.2 (10-17 years, SD 2.7). Joint laxity by the Beighton scale was assessed. Analysis of the allele distribution of the analysed genes COL1A1 and COL5A1 revealed no statistically significant difference between the study group and the control group (p = 0.859 and p = 0.205, respectively). Analysis of the Beighton score showed a statistically significantly higher result in the study group than in the control group (p < 0.001). No correlation between the presence of polymorphisms and joint laxity diagnosis was confirmed. In conclusion, COL1A1 and COL5A1 gene polymorphisms are not significantly more common in adolescents with recurrent patellar dislocation than in healthy peers; there is also no correlation between joint laxity and polymorphisms of the COL1A1 and COL5A1 genes.Registered on ClinicalTrials.gov with ID: PMMHRI-2021.2/1/7-GW.

To Test or Not to Test: Routine Thrombophilia Diagnostic Screening of Women with Reproductive Failures

BACKGROUND

Recurrent reproductive failure is a global health issue affecting a significant number of women. Thrombophilias have been implicated as a possible cause. Inherited thrombophilias include a single nucleotide variant on factor V Leiden and prothrombin.

OBJECTIVE

The aim of this study was to evaluate the association between the following single nucleotide variants: factor V Leiden (c.1601G>A), the prothrombin gene (c.*97G>A) and the reproductive failure in the Polish population.

METHODS

The study was conducted in a group of 545 patients with recurrent pregnancy loss, RPL (≥2 miscarriages), and in a group of 641 patients with infertility. The distribution of genotypes for the selected variants were determined by RFLP-PCR and by the real-time PCR method.

RESULTS

A variant of the F5 gene was found in 5.14% of patients with RPL and in 6.08% of infertile women. A variant of the F2 gene was identified in 0.73% of patients with RPL and in 2.03% of women with infertility. The frequency in the study groups did not differ from that in the general population. No association between the studied variants of the F5 gene or the F2 gene and the predisposition to reproductive wastage was found.

CONCLUSIONS

Recommendations for routine thrombophilia testing in women with recurrent miscarriages should be revisited. The decision regarding testing should be made individually depending on additional factors indicating an increased risk of venous thromboembolism.

Cytomegalovirus Infection in Pregnancy Prevention and Treatment Options: A Systematic Review and Meta-Analysis

OBJECTIVES

Cytomegalovirus (CMV) infection is a significant health concern affecting numerous expectant mothers across the globe. CMV is the leading cause of health problems and developmental delays among infected infants. Notably, this study examines CMV infection in pregnancy, its management, prevention mechanisms, and treatment options.

METHODS

Specifically, information from the Cochrane Library, PUBMED, Wiley Online, Science Direct, and Taylor Francis databases were reviewed along with additional records identified through the register, the Google Scholar search engine. Based on the search, 21 articles were identified for systematic review.

RESULTS

A total of six randomized controlled trials (RCTs) were utilized for a meta-analytic review. As heterogeneity was substantial, the random effects model was used for meta-analysis. Utilizing the random-effects model, the restricted maximum likelihood (REML) approach, the estimate of effect size (d = -0.479, 95% CI = -0.977 to 0.019, p = 0.060) suggests the results are not statistically significant, so it cannot be inferred that the prevention methods used were effective, despite an inverse relationship between treatment and number of infected cases. The findings indicated that several techniques are used to prevent, diagnose, and manage CMV infection during pregnancy, including proper hygiene, ultrasound examination (US), magnetic resonance imaging (MRI), amniocentesis, viremia, hyperimmunoglobulin (HIG), and valacyclovir (VACV).

CONCLUSIONS

The current review has significant implications for addressing CMV infection in pregnancy. Specifically, it provides valuable findings on contemporary management interventions to prevent and treat CMV infection among expectant mothers. Therefore, it allows relevant stakeholders to address these critical health concerns and understand the effectiveness of the proposed prevention and treatment options.

NGS analysis of collagen type I genes in Polish patients with Osteogenesis imperfecta: a nationwide multicenter study

Osteogenesis imperfecta (OI) is a rare genetic disorder of the connective tissue. It presents with a wide spectrum of skeletal and extraskeletal features, and ranges in severity from mild to perinatal lethal. The disease is characterized by a heterogeneous genetic background, where approximately 85%-90% of cases have dominantly inherited heterozygous pathogenic variants located in the COL1A1 and COL1A2 genes. This paper presents the results of the first nationwide study, performed on a large cohort of 197 Polish OI patients. Variants were identified using a next-generation sequencing (NGS) custom gene panel and multiplex ligation probe amplification (MLPA) assay. The following OI types were observed: 1 (42%), 2 (3%), 3 (35%), and 4 (20%). Collagen type I pathogenic variants were reported in 108 families. Alterations were observed in α1 and α2 in 70% and 30% of cases, respectively. The presented paper reports 97 distinct causative variants and expands the OI database with 38 novel pathogenic changes. It also enabled the identification of the first glycine-to-tryptophan substitution in the COL1A1 gene and brought new insights into the clinical severity associated with variants localized in "lethal regions". Our results contribute to a better understanding of the clinical and genetic aspects of OI.

Report on the Effect of the Implementation of an Early Detection and Prevention of Cancer Program on Families at High Hereditary Risk-Concentrating on Patients Undergoing Genetic Diagnostics and Counseling in Central Poland

Over a 46-month period, the objectives of the National Cancer Control Program (NCCP, pol. Narodowy Program Zwalczania Chorób Nowotworowych), coordinated by the Ministry of Health, were pursued by conducting genetic diagnostics on individuals at high risk of developing cancer. A total of 1097 individuals were enrolled in the study, leading to the identification of 128 cases of germline mutations. The implementation of the NCCP led to the identification of genetic mutations in 4.43% of the patients qualified for BRCA1 and BRCA2 screening tests, in 18.18% of those qualified for a comprehensive next-generation sequencing (NGS) panel in cases of breast and ovarian cancer, and in 17.36% of cases of colorectal and endometrial cancer. The research conducted allowed us to establish individualized preventive and therapeutic approaches for mutation carriers. However, the results prove that liberalizing the inclusion criteria for high-throughput diagnostics and the use of broad gene panels could significantly increase the percentage of detected carriers. This publication serves as a summary and discussion of the results obtained from the implementation of the NCCP as well as of the role of genetic consulting in personalized medicine.

Resistance to thyroid hormone due to a novel mutation in the thyroid beta receptor (THRβ) gene coexisting with autoimmune thyroid disease—A case report

Resistance to thyroid hormone (RTH) is a syndrome characterized by impaired responsiveness of target tissues to thyroid hormones. The relationship between RTHβ and thyroid autoimmunity has been under research. In this study, we demonstrate a case report of a woman with a novel mutation in THRβ gene coexisting with autoimmune thyroid disease (AITD). The 36-year-old woman has been treated since childhood for a thyroid disease. Based on high levels of thyroid hormones (THs) and elevated concentrations of thyroperoxidase and thyroglobulin antibodies (TPOAb and TgAb, respectively), she received unnecessary long-term treatment with methimazole and finally underwent subtotal thyroidectomy. After the surgery, her TSH level remained significantly elevated, despite the treatment with 150 + 15 µg of thyroxine and triiodothyronine. A sequence analysis of the THRβ gene revealed a novel dinucleotide substitution affecting codon 453, resulting in the replacement of the normal proline with an asparagine (c.1357_1358delinsAA, p.(Pro453Asn)). The mutation has not been described in the literature yet; however, THRβ codon 453 represents a mutational hot spot, frequently altered in the TH receptor ß gene. After establishing the diagnosis of RTH, the patient was treated with 300 µg of thyroxine, which showed clinical improvement and normalization of TSH. The coexistence of RTHβ and AITD may additionally impede establishment of a proper diagnosis, leading to unnecessary therapy and delayed correct treatment. The presented case encourages a closer cooperation between clinical endocrinologists and geneticists.

Identification of New Copy Number Variation and the Evaluation of a CNV Detection Tool for NGS Panel Data in Polish Familial Hypercholesterolemia Patients

Familial hypercholesterolemia (FH) is an inherited, autosomal dominant metabolic disorder mostly associated with disease-causing variant in LDLR, APOB or PCSK9. Although the dominant changes are small-scale missense, frameshift and splicing variants, approximately 10% of molecularly defined FH cases are due to copy number variations (CNVs). The first-line strategy is to identify possible pathogenic SNVs (single nucleotide variants) using multiple PCR, Sanger sequencing, or with more comprehensive approaches, such as NGS (next-generation sequencing), WES (whole-exome sequencing) or WGS (whole-genome sequencing). The gold standard for CNV detection in genetic diagnostics are MLPA (multiplex ligation-dependent amplification) or aCGH (array-based comparative genome hybridization). However, faster and simpler analyses are needed. Therefore, it has been proposed that NGS data can be searched to analyze CNV variants. The aim of the study was to identify novel CNV changes in FH patients without detected pathogenic SNVs using targeted sequencing and evaluation of CNV calling tool (DECoN) working on gene panel NGS data; the study also assesses its suitability as a screening step in genetic diagnostics. A group of 136 adult and child patients were recruited for the present study. The inclusion criteria comprised at least “possible FH” according to the Simon Broome diagnostic criteria in children and the DLCN (Dutch Lipid Clinical Network) criteria in adults. NGS analysis revealed potentially pathogenic SNVs in 57 patients. Thirty selected patients without a positive finding from NGS were subjected to MLPA analysis; ten of these revealed possibly pathogenic CNVs. Nine patients were found to harbor exons 4−8 duplication, two harbored exons 6−8 deletion and one demonstrated exon 9−10 deletion in LDLR. To test the DECoN program, the whole study group was referred for bioinformatic analysis. The DECoN program detected duplication of exons 4−8 in the LDLR gene in two patients, whose genetic analysis was stopped after the NGS step. The integration of the two methods proved to be particularly valuable in a five-year-old girl presenting with extreme hypercholesterolemia, with both a pathogenic missense variant (c.1747C>T) and exons 9−10 deletion in LDLR. This is the first report of a heterozygous deletion of exons 9 and 10 co-occurring with SNV. Our results suggest that the NGS-based approach has the potential to identify large-scale variation in the LDLR gene and could be further applied to extend CNV screening in other FH-related genes. Nevertheless, the outcomes from the bioinformatic approach still need to be confirmed by MLPA; hence, the latter remains the reference method for assessing CNV in FH patients.

The first glycine-to-tryptophan substitution in the COL1A1 gene identified in a patient with progressively-deforming Osteogenesis imperfecta

BACKGROUND

Osteogenesis imperfecta (OI) is a genetic disorder of connective tissue with variable phenotype and heterogeneous genetic background. Majority of reported mutations are glycine substitutions, whose clinical outcome ranges from mild to perinatal lethal. The phenotype appears to be influenced by the properties of amino acid side chain and the degree of structural aberration of collagen molecules. Since the genotype-phenotype correlation remains unclear, the severity of mutation is mostly predicted according to previously-reported cases. Although the number of OI variants is constantly expanding, no glycine-to-tryptophan substitutions have been reported in COL1A1 gene.

METHODS

A sample from a 15-year-old girl presenting with progressively-deforming OI type III was tested using an NGS custom gene panel. Multiple bioinformatic and interpretation tools, including mutation databases and conservation analysis, were used for variant classification. The presence of the mutation was verified by Sanger sequencing.

RESULTS

A novel heterozygous mutation c.733G>T was identified in the COL1A1 gene (p.Gly245Trp).

CONCLUSIONS

The discovery of this novel glycine-to-tryptophan substitution located in the COL1A1 gene broadens the spectrum of mutations underlying this rare disease and provides useful information on the clinical outcome of such substitutions.

Identification of New Genetic Determinants in Pediatric Patients with Familial Hypercholesterolemia Using a Custom NGS Panel

The most common form of inherited lipid disorders is familial hypercholesterolemia (FH). It is characterized primarily by high concentrations of the clinical triad of low-density lipoprotein cholesterol, tendon xanthomas and premature CVD. The well-known genetic background are mutations in LDLR, APOB and PCSK9 gene. Causative mutations can be found in 60−80% of definite FH patients and 20−30% of those with possible FH. Their occurrence could be attributed to the activity of minor candidate genes, whose causal mechanism has not been fully discovered. The aim of the conducted study was to identify disease-causing mutations in FH-related and candidate genes in pediatric patients from Poland using next generation sequencing (NGS). An NGS custom panel was designed to cover 21 causative and candidate genes linked to primary dyslipidemia. Recruitment was performed using Simon Broome diagnostic criteria. Targeted next generation sequencing was performed on a MiniSeq sequencer (Illumina, San Diego, CA, USA) using a 2 × 150 bp paired-end read module. Sequencing data analysis revealed pathogenic and possibly pathogenic variants in 33 out of 57 studied children. The affected genes were LDLR, APOB, ABCG5 and LPL. A novel pathogenic 7bp frameshift deletion c.373_379delCAGTTCG in the exon 4 of the LDLR gene was found. Our findings are the first to identify the c.373_379delCAGTTCG mutation in the LDLR gene. Furthermore, the double heterozygous carrier of frameshift insertion c.2416dupG in the LDLR gene and missense variant c.10708C>T in the APOB gene was identified. The c.2416dupG variant was defined as pathogenic, as confirmed by its cosegregation with hypercholesterolemia in the proband’s family. Although the APOB c.10708C>T variant was previously detected in hypercholesterolemic patients, our data seem to demonstrate no clinical impact. Two missense variants in the LPL gene associated with elevated triglyceride plasma level (c.106G>A and c.953A>G) were also identified. The custom NGS panel proved to be an effective research tool for identifying new causative aberrations in a genetically heterogeneous disease as familial hypercholesterolemia (FH). Our findings expand the spectrum of variants associated with the FH loci and will be of value in genetic counseling among patients with the disease.

Familial Partial Lipodystrophy-Literature Review and Report of a Novel Variant in PPARG Expanding the Spectrum of Disease-Causing Alterations in FPLD3

Familial partial lipodystrophy (FPLD) is a rare genetic disorder characterized by the selective loss of adipose tissue. Its estimated prevalence is as low as 1 in 1 million. The deficiency of metabolically active adipose tissue is closely linked with a wide range of metabolic complications, such as insulin resistance, lipoatrophic diabetes, dyslipidemia with severe hypertriglyceridemia, hypertension or hepatic steatosis. Moreover, female patients often develop hyperandrogenism, hirsutism, polycystic ovaries and infertility. The two most common types are FPLD type 2 and 3. Variants within LMNA and PPARG genes account for more than 50% of all reported FPLD cases. Because of its high heterogeneity and rarity, lipodystrophy can be easily unrecognized or misdiagnosed. To determine the genetic background of FPLD in a symptomatic woman and her close family, an NGS custom panel was used to sequence LMNA and PPARG genes. The affected patient presented fat deposits in the face, neck and trunk, with fat loss combined with muscular hypertrophy in the lower extremities and hirsutism, all features first manifesting at puberty. Her clinical presentation included metabolic disturbances, including hypercholesterolemia with severe hypertriglyceridemia, diabetes mellitus and hepatic steatosis. This together with her typical fat distribution and physical features raised a suspicion of FPLD. NGS analysis revealed the presence of missense heterozygous variant c.443G>A in exon 4 of PPARG gene, causing glycine to glutamic acid substitution at amino acid position 148, p.(Gly148Glu). The variant was also found in the patient’s mother and son. The variant was not previously reported in any public database. Based on computational analysis, crucial variant localization within DNA-binding domain of PPARγ, available literature data and the variant cosegregation in the patient’s family, novel c.443G>A variant was suspected to be causative. Functional testing is needed to confirm the pathogenicity of the novel variant. Inherited lipodystrophy syndromes represent a heterogenous group of metabolic disorders, whose background often remains unclear. A better understating of the genetic basis would allow earlier diagnosis and targeted treatment implementation.

Amniocentesis in Twin Pregnancies: Risk Factors of Fetal Loss

This study aims to determine if second trimester amniocentesis in twin pregnancies provides a significant independent contribution in the prediction of miscarriage or fetal loss at any stage of pregnancy. This was a retrospective cohort study of women with twin gestations booked for routine prenatal care in four fetal medicine units in Poland in the years 2010-2020. The study population included: (1) twin pregnancies that underwent amniocentesis at 16-20 weeks' gestation; (2) twin pregnancies that did not require any further testing and were followed-up routinely. Univariable and multivariable regression analysis was used to define which maternal and pregnancy characteristics provided a significant independent contribution in the prediction of miscarriage and fetal loss at any stage of pregnancy. In the study period, 2645 twin pregnancies were eligible for analysis. There were 144 cases of miscarriage defined as fetal loss of one or both twins before 24 weeks and 40 cases of intrauterine death of one or both twins after 24 weeks. A total number of 162 twin pregnancies underwent amniocentesis at 16-20 weeks' gestation. The rate of miscarriage before 24 weeks and the rate of fetal loss at any stage of pregnancy in the group that underwent amniocentesis was 10.49% and 13.58%, respectively, compared to 5.11% and 6.52% that did not undergo amniocentesis. Multivariable regression analysis showed that factors providing a significant independent contribution in the prediction of miscarriage and fetal loss at any stage of pregnancy were monochorionicity (MC), large intertwin discordance in crown-rump length (CRL), low Pregnancy Related Plasma Protein (PAPP-A) MoM and nuchal translucency (NT) above 95th centile. Amniocentesis in twin pregnancies does not provide a significant contribution in the prediction of miscarriage or fetal loss at any stage of pregnancy.

New findings in oligogenic inheritance of congenital hypogonadotropic hypogonadism

INTRODUCTION

Congenital hypogonadotropic hypogonadism results from a dysfunction of the hypothalamic-pituitary-gonadal axis, which is essential for the development and function of the reproductive system. It may be associated with anosmia, referred to as Kallmann syndrome, or a normal sense of smell. Numerous studies have proven that hypogonadotropic hypogonadism is not simply a monogenic Mendelian disease, but that more than one gene may be involved in its pathogenesis in a single patient. The oligogenic complex architecture underlying the disease is still largely unknown.

MATERIAL AND METHODS

Targeted next-generation sequencing (NGS) was used to screen for DNA variants in a cohort of 47 patients with congenital hypogonadotropic hypogonadism. The NGS panel consists of over 50 well-known and candidate genes, associated with hypogonadotropic state.

RESULTS

Here we report the identification of new oligogenic variants in SPRY4/SEMA3A, SRA1/SEMA7A, CHD7/SEMA7A, CCDC141/POLR3B/POLR3B, and PROKR2/SPRY4/NSMF. These genes are known to contribute to the phenotype of hypogonadotropic hypogonadism, yet our results point to potential new "partners" underlying digenic and trigenic patterns.

CONCLUSIONS

The finding supports the importance of oligogenic inheritance and demonstrates the complexity of genetic architecture in hypogonadotropic hypogonadism. It also underlines the necessity for developing fine-tuned guidelines to provide a tool for adequate and precise sequence variant classification in non-Mendelian conditions.

No evidence for change in expression of TBC1D1 and TBC1D4 genes in cultured human adipocytes stimulated by myokines and adipokines

TBC1D1 and TBC1D4 proteins play analogous, but not identical role in governing insulin-signalling pathway. Little is known about changes in expression levels of TBC1D1 and TBC1D4 genes in mammals, including humans. Number of factors were studied, but data remain controversial. The aim of this study was to evaluate the effect of selected cytokines, adipokines and myokines with known or putative insulin sensitivity regulation activity (adiponectin, irisin, omentin, interleukin 6, leptin, resistin, and tumour necrosis factor) on TBC1D1 and TBC1D4 expression levels in cultured differentiated human adipocytes. No significant differences were found between the adipocytes treated with different stimuli and this effect was determined not dose dependent. It is reasonable to conclude that relative shortage of data showing no change in TBC1D1 and TBC1D4 from literature results from publication bias; therefore, our finding provides additional insight into the role of both genes.

Chromogranin A demonstrates higher expression in preeclamptic placentas than in normal pregnancy

BACKGROUND

Although preeclampsia has long been recognized as a condition affecting late pregnancy, little is known of its pathogenesis or treatment. The placenta releases a number of hormones and molecules that influence the course of pregnancy, one of which is chromogranin A, a soluble protein secreted mainly from the chromaffin cells of the adrenal medulla. Its role in pregnancy and pregnancy-related disorders remains unclear. Therefore, the main aim of the proposed study is to determine whether chromogranin A is related with the occurrence of preeclampsia.

METHODS

Placental samples were collected from 102 preeclamptic patients and 103 healthy controls, and Chromogranin A gene (CHGA) expression was measured using real-time RT-PCR, The RT-PCR results were verified on the protein level using ELISA. The normal distribution of the data was tested using the Shapiro-Wilk test. The clinical and personal characteristics of the groups were compared using the Student's t-test for normally-distributed data, and the χ2 test for categorical variables. The Mann-Whitney U test was used for non-normally distributed data. As the log- transformation was not suitable for the given outcomes, the Box- Cox Transformation was used to normalize data from ELISA tests and CHGA expression. Values of P < .05 were considered statistically significant.

RESULTS

Chromogranin A gene expression was found to be significantly higher in the study group than in controls. Protein analyses showed that although the CgA concentration in placental samples did not differ significantly, the catestatin (CST) level was significantly lower in samples obtained from women with preeclampsia, according to the controls.

CONCLUSIONS FOR PRACTICE

This study for the first time reveals that chromogranin A gene expression level is associated with preeclampsia. Moreover, the depletion in catestatin level, which plays a protective role in hypertension development, might be a marker of developing preeclampsia. Further studies may unravel role of Chromogranin A in the discussed disease.

The Influence of Maternal Cell Contamination on Fetal Aneuploidy Detection Using Chip-Based Digital PCR Testing

Prenatal samples obtained by amniocentesis or chorionic villus sampling are at risk of maternal cell contamination (MCC). In traditional prenatal analysis, MCC is recommended to be assayed by special tests, such as the short tandem repeat analysis and, if detected at a high level, may result in failed analysis report. The objective of this study was to test the ability of chip-based digital PCR to detect fetal aneuploidies in the presence of MCC. To determine the level of accuracy of MCC detection, an aneuploid male sample was subjected to serial dilution with an euploid female sample. DNA was extracted from prenatal samples and analyzed with QuantStudio 3D Digital PCR. Digital PCR analysis allowed the detection of trisomy 21, trisomy 18, and X monosomy accurately in samples with 90%, 85%, and 92% of MCC, respectively. Moreover, our results indicated that digital PCR was able to accurately confirm the presence of Y chromosome at up to 95% contamination. The amniotic fluid and chorionic villus sampling (CVS) received in our clinical laboratory was subjected to further analysis of MCC based on the aneuploidy assessment algorithm, resulting in the identification of 10 contaminated samples and four cases of true fetal mosaicism. We conclude that chip-based digital PCR analysis enables the detection of fetal aneuploidy with high levels of accuracy, even in cases of significant MCC. Importantly, the algorithm eliminates the need for maternal DNA and additional MCC tests, which reduces costs and simplifies the diagnostic procedure. The method is easy to set up and suitable for routine clinical practice.

Novel Mutations Within Collagen Alpha1(I) and Alpha2(I) Ligand-Binding Sites, Broadening the Spectrum of Osteogenesis Imperfecta - Current Insights Into Collagen Type I Lethal Regions

Osteogenesis imperfecta (OI) is a rare genetic disorder demonstrating considerable phenotypic and genetic heterogeneity. The extensively studied genotype-phenotype correlation is a crucial issue for a reliable counseling, as the disease is recognized at increasingly earlier stages of life, including prenatal period. Based on population studies, clusters in COL1A1 and COL1A2 genes associated with the presence of glycine substitutions leading to fatal outcome have been distinguished and named as "lethal regions." Their localization corresponds to the ligand-binding sites responsible for extracellular interactions of collagen molecules, which could explain high mortality associated with mutations mapping to these regions. Although a number of non-lethal cases have been identified from the variants located in lethal clusters, the mortality rate of mutations has not been updated. An next generation sequencing analysis, using a custom gene panel of known and candidate OI genes, was performed on a group of 166 OI patients and revealed seven individuals with a causative mutations located in the lethal regions. Patients' age, ranging between 3 and 25 years, excluded the expected fatal outcome. The identification of non-lethal cases caused by mutations located in lethal domains prompted us to determine the actual mortality caused by glycine substitutions mapping to lethal clusters and evaluate the distribution of all lethal glycine mutations across collagen type I genes, based on records deposited in the OI Variant Database. Finally, we identified six glycine substitutions located in lethal regions of COL1A1 and COL1A2 genes, of which four are novel. The review of all mutations in the dedicated OI database, revealed 33 distinct glycine substitutions in two lethal domains of COL1A1, 26 of which have been associated with a fatal outcome. Similarly, 109 glycine substitutions have been identified in eight lethal clusters of COL1A2, of which 51 have been associated with a fatal manifestation. An analysis of all glycine substitutions leading to fatal phenotype, showed that their distribution along collagen type I genes is not regular, with 17% (26 out of 154) of mutations reported in COL1A1 and 64% (51 out of 80) in COL1A2 corresponding to localization of the lethal regions.

A Novel Intronic Splice-Site Mutation of the CYP11A1 Gene Linked to Adrenal Insufficiency with 46,XY Disorder of Sex Development

A novel CYP11A1: c.1236 + 5G > A was identified, expanding the mutation spectrum of the congenital adrenal insufficiency with 46,XY sex reversal. In a now 17-year-old girl delivered full-term (G2P2, parents unrelated), adrenal failure was diagnosed in the first year of life based on clinical picture of acute adrenal crisis with vomiting, dehydration, weight loss, hypotension, and electrolyte disturbances. At the time, hormonal tests revealed primary adrenocortical insufficiency and steroid profiles showed lack of products of steroidogenesis, and since then the patient has been treated with substitution doses of hydrocortisone and fludrocortisone. At the age of 14, considering the absence of puberty symptoms, extended diagnostic tests revealed elevated LH levels (26.5 mIU/mL) with pre-puberty FSH levels (4.9 mIU/mL), low estradiol (28 pmol/L), testosterone (<2.5 ng/mL), and extremely high levels of ACTH (4961 pg/mL). A cytogenetic study revealed a 46 XY karyotype. A molecular examination confirmed the missense mutation and a novel splice-site mutation of CYP11A1 gene. Compound heterozygosity for the CYP11A1 gene with a known pathogenic variant in one allele and a novel splice site mutation in the second allele is most probably responsible for congenital adrenal insufficiency with 46,XY sex reversal. We discuss the necessity of cytogenetic test in the case of early onset of adrenal failure in the absence of steroidogenesis metabolites in the steroid profile.

Clinical Validation of Novel Chip-Based Digital PCR Platform for Fetal Aneuploidies Screening

Fetal aneuploidy is routinely diagnosed by karyotyping. The development of techniques for rapid aneuploidy detection based on the amplification reaction allows cheaper and rapid diagnosis. However, the currently available solutions have limitations. We tested a novel approach as a diagnostic tool in clinical practice. The objective of this study was to provide a clinical performance of the sensitivity and specificity of a novel chip-based digital PCR approach for fetal aneuploidy screening. The study was conducted in 505 pregnant women with increased risk for fetal aneuploidy undergoing invasive prenatal diagnostics. DNA extracted from amniotic fluid or CVS was analyzed for the copy number of chromosomes 13, 18, 21, X, and Y using a new chip-based solution. Performance was assessed by comparing results with findings from karyotyping. Aneuploidy was confirmed in 65/505 cases positive for trisomy 21, 30/505 cases positive for trisomy 18, 14/505 cases positive for trisomy 13 and 21/505 with SCAs. Moreover, 2 cases with triploidy and 2 cases with confirmed mosaicisms of 21 and X chromosomes were detected. Clinical sensitivity and specificity within this study was determined at 100% for T21 (95% CI, 99.26–100%), T18 (95% CI, 99.26–100%), and T13 (95% CI, 99.26–100%). Chip-based digital PCR provides equally high sensitivity and specificity in rapid aneuploidy screening and can be implemented into routine prenatal diagnostics.

Association between idiopathic recurrent pregnancy loss and genetic polymorphisms in cytokine and matrix metalloproteinase genes

OBJECTIVES

Recurrent reproductive loss (RPL) is a global health issue affecting a significant number of women. Approximately half of miscarriages have an unexplained etiology. Familial aggregation and twins studies prove that some cases of the RPL could have a genetic background. Recent evidences suggest that cytokines (e.g. IL-6, TNF alpha or TGF beta) and matrix metalloproteinases (MMP) are important for maintenance of pregnancy. Single gene polymorphisms (SNP), affecting these proteins production or their function may predispose to the loss of the pregnancy. The aim of this study was to evaluate the association between the following polymorphisms of IL6 (rs1800795), TNF (rs1800629), TGFB1 (rs1800471), MMP1 (rs1799750), MMP2 (rs2285053 and rs243865), MMP3 (rs35068180), MMP9 (rs3918242) and the recurrent pregnancy loss in polish population.

MATERIAL AND METHODS

Study subjects comprised of 67 patients with a history of recurrent pregnancy loss (≥ 2 miscarriages in history) and 75 controls. The distribution of genotypes for selected polymorphisms were determined by RFLP-PCR.

RESULTS

Maternal genotypes GG TNF, or 5A/5A MMP3 may be associated with the recurrent pregnancy loss. No association between the IL6, TGFB1, MMP1, MMP2, or MMP9 studied polymorphisms and the predisposition to miscarriage was found.

CONCLUSIONS

This study demonstrated a possible association between rs1800629 TNF, rs35068180 MMP3 polymorphisms and recurrent pregnancy loss.

Broad phenotypic spectrum of germ line 7p12.1 microdeletions encompassing the IKZF1 gene includes predisposition to acute lymphoblastic leukemia

Microdeletions of 7p12.1 encompassing the IKZF1 gene locus are rare, with few cases reported. The common phenotype includes intellectual disability, overgrowth, and facial dysmorphism accompanied, albeit rarely, by congenital anomalies. Haploinsufficiency of IKZF1 predisposes individuals to childhood acute lymphoblastic leukemia (ALL). In this study, we comprehensively analyzed the frequency of 7p12.1 deletions among 4581 Polish individuals who underwent chromosomal microarray testing for unexplained developmental delay, intellectual disability, and/or congenital anomalies. Two unrelated individuals (0.04%) with a de novo interstitial 7p12.1 microdeletion encompassing IKZF1 were identified. One developed ALL. Analysis of the incidence and the phenotype of constitutional 7p12.1 microdeletion, which based on the previously annotated patients data in public databases and literature reports, revealed 21 cases including five patients diagnosed with ALL.

Identification of gene variants in a cohort of hypogonadotropic hypogonadism: Diagnostic utility of custom NGS panel and WES in unravelling genetic complexity of the disease

Congenital hypogonadotropic hypogonadism (CHH) is caused by dysfunction of hypothalamic gonadotropic-releasing hormone (GnRH) axis. The condition is both clinically and genetically heterogeneous with more than 40 genes implicated in pathogenesis. The goal of the present study was to identify causative mutations in CHH individuals employing 2 step procedure with a targeted NGS panel as first-line diagnostics and subsequently whole exome sequencing in unsolved cases. Known or novel potentially deleterious variants were found in 28 out of 47 tested CHH patients. Molecular diagnosis was reached in 19/47 CHH cases. In 13 cases monogenic variants were identified in ANOS1, FGFR1, GNRHR, CHD7, SOX10, and PROKR2, while 6 patients showed digenic or trigenic inheritance patterns. The achieved diagnostic rate was comparable to other studies on genetics of CHH. By evaluating and reporting more patients with CHH we make progress in unravelling its genetic complexity and move a step closer to personalised medicine.

Canonical, Non-Canonical and Atypical Pathways of Nuclear Factor кb Activation in Preeclampsia

Although higher nuclear factor κB (NFκB) expression and activity is observed in preeclamptic placentas, its mechanism of activation is unknown. This is the first study to investigate whether the canonical, non-canonical, or atypical NFκB activation pathways may be responsible for the higher activation of NFκB observed in preeclamptic placentas. The study included 268 cases (130 preeclamptic women and 138 controls). We studied the expression of the genes coding for NFκB activators (NIK, IKKα, IKKβ, and CK2α) and inhibitors (IκBα and IκBβ) using RT-PCR in real time. The RT-PCR results were verified on the protein level using ELISA and Western blot. To determine the efficiency of the pathways, the ratios of activator(s) to one of the inhibitors (IκBα or IκBβ) were calculated for each studied pathway. The preeclamptic placentas demonstrated significantly lower IKKα and CK2α but higher IκBα and IκBβ protein levels. In addition, the calculated activator(s) to inhibitor (IκBα or IκBβ) ratios suggested that all studied pathways might be downregulated in preeclamptic placentas. Our results indicate that preeclamptic placentas may demonstrate mechanisms of NFκB activation other than the canonical, non-canonical, and atypical forms. In these mechanisms, inhibitors of NFκB may play a key role. These observations broaden the existing knowledge regarding the molecular background of preeclampsia development.

Expanding the mutational spectrum of monogenic hypogonadotropic hypogonadism: novel mutations in ANOS1 and FGFR1 genes

BACKGROUND

Congenital hypogonadotropic hypogonadism (CHH) is a rare disease, triggered by defective GnRH secretion, that is usually diagnosed in late adolescence or early adulthood due to the lack of spontaneous pubertal development. To date more than 30 genes have been associated with CHH pathogenesis with X-linked recessive, autosomal dominant, autosomal recessive and oligogenic modes of inheritance. Defective sense of smell is present in about 50-60% of CHH patients and called Kallmann syndrome (KS), in contrast to patients with normal sense of smell referred to as normosmic CHH. ANOS1 and FGFR1 genes are all well established in the pathogenesis of CHH and have been extensively studied in many reported cohorts. Due to rarity and heterogenicity of the condition the mutational spectrum, even in classical CHH genes, have yet to be fully characterized.

METHODS

To address this issue we screened for ANOS1 and FGFR1 variants in a cohort of 47 unrelated CHH subjects using targeted panel sequencing. All potentially pathogenic variants have been validated with Sanger sequencing.

RESULTS

Sequencing revealed two ANOS1 and four FGFR1 mutations in six subjects, of which five are novel and one had been previously reported in CHH. Novel variants include a single base pair deletion c.313delT in exon 3 of ANOS1, three missense variants of FGFR1 predicted to result in the single amino acid substitutions c.331C > T (p.R111C), c.1964 T > C (p.L655P) and c.2167G > A (p.E723K) and a 15 bp deletion c.374_388delTGCCCGCAGACTCCG in exon 4 of FGFR1. Based on ACMG-AMP criteria reported variants were assigned to class 5, pathogenic or class 4, likely pathogenic. Protein structural predictions, the rarity of novel variants and amino acid conservation in case of missense substitutions all provide strong evidence that these mutations are highly likely to be deleterious.

CONCLUSIONS

Despite the fact that ANOS1 and FGFR1 are classical CHH genes and were thoroughly explored in several CHH cohorts we identified new, yet undescribed variants within their sequence. Our results support the genetic complexity of the disorder. The knowledge of the full genetic spectrum of CHH is increasingly important in order to be able to deliver the best personalised medical care to our patients.

The level of extracellular superoxide dismutase in the first week of life in very and extremely low birth weight infants and the risk of developing bronchopulmonary dysplasia

Background Antioxidant enzymes may play a significant role in the development of bronchopulmonary dysplasia (BPD). The aim of the study was to assess the relationship between the level of extracellular superoxide dismutase (SOD3) in the serum at days 1 and 7 of life and the risk of developing BPD. Methods The study comprised 103 neonates born before 32 weeks' gestation with a birth weight of ≤1500 g. Results In the investigated group, the median serum SOD3 level at day 1 of life was 4.01 ng/mL [interquartile range (IQR) 2.59-5.09 ng/mL] and at day 7 of life 3.13 ng/mL (IQR 2.49-4.34 ng/mL). A statistically significant decrease in the serum SOD3 level was found in the first week of life, P < 0.0001. No correlation was found between the serum SOD3 level at day 1 of life and gestational age R = 0.07, P = 0.4543 and birth weight R = 0.10, P = 0.3083. No statistically significant correlation was found between the dynamics of change in the SOD3 level in serum at days 1 and 7 of life and the risk of BPD development for the definition of BPD at day 28 of life, P = 0.8764 nor at 36 weeks' postmenstrual age, P = 0.6598. Conclusion The study revealed a statistically significant decrease in the serum SOD3 level in the first week of life in very and extremely low birth weight infants born before 32 weeks of gestation. In the clinical setting, no relationship was observed between the level of SOD3 in serum and the risk of developing BPD.

Double hit of NEMO gene in preeclampsia

The precise etiology of preeclampsia is unknown. Family studies indicate that both genetic and environmental factors influence its development. One of these factors is NFkB, whose activation depends on NEMO (NFkB essential modulator. This is the first study to investigate the association between the existence of single nucleotide variant of the NEMO gene and the appearance of preeclampsia. A total of 151 women (72 preeclamptic women and 79 controls) and their children were examined. Sanger sequencing was performed to identify variants in the NEMO gene in the preeclamptic mothers. The maternal identified variants were then sought in the studied groups of children, and in the maternal and child controls, using RFLP-PCR. Real-time RT-PCR was performed to assess NEMO gene expression in maternal blood, umbilical cord blood and placentas. The sequencing process indicated the existence of two different variants in the 3'UTR region of the NEMO gene of preeclamptic women (IKBKG:c.*368C>A and IKBKG:c.*402C>T). The simultaneous occurrence of the TT genotype in the mother and the TT genotype in the daughter or a T allele in the son increased the risk of preeclampsia development 2.59 fold. Additionally, we found that the configuration of maternal/fetal genotypes (maternal TT/ daughter TT or maternal TT/son T) of IKBKG:c.*402C/T variant is associated with the level of NEMO gene expression. Our results showed that, the simultaneous occurrence of the maternal TT genotype (IKBKG:c.*402C>T variants) and TT genotype in the daughter or T allele in the son correlates with the level of NEMO gene expression and increases the risk of preeclampsia development. Our observations may offer a new insight into the genetic etiology and pathogenesis of preeclampsia.

Familial partial lipodystrophy as differential diagnosis of polycystic ovary syndrome

According to current diagnostic criteria, polycystic ovary syndrome (PCOS) is effective as a diagnosis of exclusion. Here, we present a case of a 31-year-old woman with a history of oligomenorrhoea and hirsutism, who, despite a "muscular" appearance and a normal body mass index (22.27 kg/m2), was found to have an extreme insulin resistance and diabetes accompanied by hyperandrogenism and polycystic ovaries. An autoimmune screen for possible latent autoimmune diabetes in adults was negative. She was subsequently found to have familial partial lipodystrophy (FPLD2, OMIM #151660) caused by an R482Q mutation in the LMNA gene encoding lamin A/C. This mutation results in arginine to glutamine substitution at the protein level, while phenotypically this condition presents with a loss of body fat, insulin resistance, dyslipidaemia, and other features mimicking PCOS. Interestingly her mother, with a history of myocardial infarction and diabetes at the age of 46 but no oligomenorrhoea, was also found to harbour the same mutation (LMNA R482Q).

CONCLUSIONS

Our case highlights the importance of assessment of adipose tissue distribution, as well as a significance of assessment of glucose tolerance and insulin resistance in the differential diagnosis of PCOS. Furthermore, patients with atypical adipose tissue distribution should be referred for formal genetic testing.

Finding NEMO in preeclampsia

BACKGROUND

The mechanism of preeclampsia and its way of inheritance are still a mystery. Biochemical and immunochemical studies reveal a substantial increase in tumor necrosis factor alpha, interleukin-1 beta, and interleukin-6 concentrations in the blood of women with preeclampsia. The level of these factors is regulated by nuclear facxtor-kappa B, whose activation in a classical pathway requires inhibitory kappa B kinase gamma (known as NEMO or IKBKG). Moreover, NEMO can schedule between cytoplasma and the nucleus. In the nucleus, IKBKG interacts with other proteins, and thus, it is implicated in the regulation of different gene expressions, which are related to cell cycle progression, proliferation, differentiation, and apoptosis.

OBJECTIVE

This is the first study investigating the association between the level of NEMO gene expression and the presence of preeclampsia. We tested the hypothesis that the simultaneous increase in NEMO gene expression both in the mother and her fetus may be responsible for the preeclampsia development. Moreover, the relationships between clinical risk factors of preeclampsia and the levels of NEMO gene expression in blood, umbilical cord blood, and placentas were investigated.

STUDY DESIGN

A total of 91 women (43 preeclamptic women and 48 controls) and their children were examined. Real-time reverse transcription-polymerase chain reaction was used to assess the amount total NEMO messenger ribonucleic acid (mRNA) content and the mRNA level of each NEMO transcript from exons 1A, 1B, and 1C in maternal blood, umbilical cord blood, and placentas. Univariate analyses and correlation tests were performed to examine the association between NEMO gene expression and preeclampsia.

RESULTS

Newborn weight and height, maternal platelet number, and gestational age (week of delivery) were lower in the group of women with preeclampsia than controls. NEMO gene expression level was found to be almost 7 times higher in the group of women with preeclampsia than healthy controls. The correlation analysis found that a simultaneous increase in the expression level of total NEMO mRNA in maternal blood and the mRNA for total NEMO (Rs = 0.311, P < .05), transcripts 1A (Rs = 0.463, P < .01), 1B (Rs = 0.454, P < .01), and 1C (Rs = 0.563, P < .001) in fetal blood was observed in preeclamptic pregnancies. In addition, the mRNA levels for total NEMO and transcripts 1A, 1B, and 1C were lower in placentas derived from pregnancies complicated by preeclampsia.

CONCLUSION

Simultaneous increase of NEMO gene expression in maternal and fetal blood seems to be relevant for preeclampsia development. The results of our study also suggest that a decreased NEMO gene expression level in preeclamptic placentas may be the main reason for their intensified apoptosis.

The first case report of sulfonylurea use in a woman with permanent neonatal diabetes mellitus due to KCNJ11 mutation during a high-risk pregnancy

Sulfonylureas (SUs) were proven to be more effective than insulin in most Kir6.2 permanent neonatal diabetes mellitus (PNDM) patients. We report SU use during pregnancy in PNDM. A woman with the R201H Kir6.2 mutation became pregnant at the age of 37. The patient had been on glipizide 30 mg for 3 yr; her glycosylated hemoglobin level was 5.8%. She was diagnosed with chronic diabetes complications and a congenital defect of the urogenitary tract-a bicornuate uterus with septum. Because the effect of SU on fetal development is uncertain, she was switched to insulin after the pregnancy diagnosis; however, the subsequent glycemic control was unsatisfactory, with episodes of hyper- and hypoglycemia. Thus, in the second trimester, the patient was transferred to SU (glibenclamide, 40 mg), which resulted in stabilization of glycemic control; glycosylated hemoglobin in the third trimester was 5.8%. Prenatal genetic testing excluded the Kir6.2 R201H mutation in the fetus. A preterm cesarean delivery was carried out in the 35th week. The Apgar score of the newborn boy (weight, 3010 g; 75th percentile) was 8 at 1 min. He presented with hypoglycemia, transient tachypnea of the newborn, and hyperbilirubinemia. The recovery was uneventful. No birth defects were recorded. His development at the ninth month of life was normal. In summary, we show a high-risk pregnancy in long-term PNDM that despite perinatal complications ended with the birth of a healthy child. SUs, which seem to constitute an alternative to insulin during pregnancy in Kir6.2-related PNDM, were used during the conception period and most of the second and third trimesters.

Efficacy and safety of sulfonylurea use in permanent neonatal diabetes due to KCNJ11 gene mutations: 34-month median follow-up

BACKGROUND

Recently, many patients with Kir6.2-related permanent neonatal diabetes mellitus (PNDM) have been successfully transferred from insulin therapy to sulfonylurea (SU) treatment. The long-term efficacy and safety of SU treatment in PNDM patients, however, have not yet been determined.

METHODS

We monitored glycemic control and the occurrence of potential side effects in 14 Kir6.2-related PNDM patients from Poland (median age, 12.0 years; range, 5-50 years) who were transferred to SU therapy at least 2 years ago. Three of the 14 patients were lost to follow-up, whereas for the remaining 11 individuals the median follow-up was 34 months (range, 27-51 months).

RESULTS

The initial reduction of glycated hemoglobin (HbA1c) after the switch to SU (approximately 3-6 months post-transfer) was 1.68% (range, 0.3-3.7%), and good metabolic control was maintained over the entire period of observation with an average HbA1c level of 6.0% (range, 5.3-6.7%) at the last visit. This was accompanied by a substantial drop in SU dose by 0.24 mg/kg, which constituted a 38.0% decrease. A rapid progression of retinal changes was observed in one patient, a 34-year-old woman at the beginning of the observation, with preexisting proliferative diabetic retinopathy. No causal relationship between these changes and SU treatment could be proven. Neither serious side effects nor progression of diabetes complications was observed in any other patients. No detrimental effect on growth in the observed minors was recorded.

CONCLUSIONS

In summary, the switch from insulin therapy to SU treatment in PNDM related to KCNJ11 mutations was found to be an efficient and safe therapeutic method over a period of 34-month median follow-up. Although no serious side effects were associated with SU treatment, their use in Kir6.2 PNDM requires further attention, particularly in children, adolescents, and patients with advanced chronic diabetes complications.

Neonatal diabetes in a child positive for islet cell antibodies at onset and Kir6.2 activating mutation

In contrast to the autoimmune type 1 diabetes, patients with monogenic diabetes due to KCNJ11 mutations do not have pancreatic auto-antibodies at onset. Here we describe a patient diagnosed at the age of 12 weeks that showed ICA at diagnosis, yet has been tested with positive result for KCNJ11 mutation.

[Permanent neonatal diabetes with known genetic background: oral drugs in treatment of childhood diabetes]

Diabetes, which is diagnosed before 6 months of age, is patogenetically different than type 1 diabetes. This kind of diabetes also known as a neonatal diabetes is genetically determined with monogenic mode of inheritance. Most of these patients are carriers of heterozygous mutation in the KCNJ11 or ABCC8 gene. These mutations may activate the Kir6.2/SUR1 potassium channel in the beta cells and disturb insulin secretion, which in consequence leads to diabetes. This patological phenomenon is reversible if sulfonylureas are used as a first line therapy. In the current paper a systematic review of clinical aspects of sulfonylurea treatment in neonatal diabetes has been performed. This gives the further evidence that knowlegde of the patogenesis of neonatal diabetes may be easily transferred to bedside and clinical practice.

Sulfonylurea improves CNS function in a case of intermediate DEND syndrome caused by a mutation in KCNJ11

BACKGROUND

A 12-week-old female presented with neonatal diabetes. Insulin therapy alleviated the diabetes, but the patient showed marked motor and mental developmental delay. The patient underwent genetic evaluation at the age of 6 years, prompted by reports that mutations in the KCNJ11 gene caused neonatal diabetes.

INVESTIGATIONS

Genomic sequencing of the ATP-sensitive potassium (K(ATP)) channel gene KCNJ11 and in vitro functional analysis of the channel defect, and single-photon emission CT imaging before and after glibenclamide therapy.

DIAGNOSIS

Genetic evaluation revealed a missense mutation (His46Leu) in KCNJ11, which encodes the Kir6.2 subunit of the K(ATP) channel, conferring reduced ATP sensitivity. Functional studies demonstrated that the mutant channels were strongly inhibited by the sulfonylurea tolbutamide.

MANAGEMENT

Sulfonylurea (glibenclamide) treatment led to both improved glucose homeostasis and an increase in mental and motor function.

Assessment of insulin sensitivity in adults with permanent neonatal diabetes mellitus due to mutations in the KCNJ11 gene encoding Kir6.2

Activating mutations in the KCNJ11 gene encoding the Kir6.2 subunit of ATP-sensitive potassium channel have been described in patients with permanent neonatal diabetes mellitus (PNDM). The main pathophysiological feature of PNDM associated with Kir6.2 mutations is a profound defect in insulin secretion. However, the expression of Kir6.2 protein is not limited to beta-cells; it also includes skeletal muscles, heart, brain, and peripheral nerves. Thus, the hypothesis that Kir6.2 mutations may influence insulin sensitivity in humans seems justified. Moreover, this notion is additionally supported by an animal model of Kir6.2 knock-out mice. Four adult carriers of a Kir6.2 mutation from the Polish population (mean age 31.5 years, range 20-50) were available for this study that aimed to evaluate their insulin sensitivity by the hyperinsulinemic euglycemic clamp technique. Three subjects carried the R201H mutation and one patient was a carrier of the K170N mutation. In addition, eight healthy volunteers with normal glucose tolerance were examined for comparison (mean age 31.0 years, range 20-41). The mean M value, i.e. the amount of metabolized glucose, for PNDM cases equaled 4.49 mg/(kg x min) (range 2.76-6.66) and was significantly lower than in the control group (9.64 mg/(kg x min), range 4.59-18.00). This observation suggests that impaired insulin sensitivity, in addition to profoundly decreased insulin secretion, contributes to the clinical picture of PNDM resulting from mutations in the Kir6.2 gene. An additional factor that might influence insulin sensitivity in our diabetes patients is glucose toxicity that may have appeared due to poor metabolic control prior to the examination (mean HbA1c = 8.95%). The intriguing question to be answered in the future is whether an improvement in insulin action could be seen following the transfer of Kir6.2 mutation carriers to sulphonylurea compounds.

Selective Loss of Fine Tuning of Gq/11 Signaling by RGS2 Protein Exacerbates Cardiomyocyte Hypertrophy

Alterations in cardiac G protein-mediated signaling, most prominently G(q/11) signaling, are centrally involved in hypertrophy and heart failure development. Several RGS proteins that can act as negative regulators of G protein signaling are expressed in the heart, but their functional roles are still poorly understood. RGS expression changes have been described in hypertrophic and failing hearts. In this study, we report a marked decrease in RGS2 (but not other major cardiac RGS proteins (RGS3-RGS5)) that occurs prior to hypertrophy development in different models with enhanced G(q/11) signaling (transgenic expression of activated Galpha(q)(*) and pressure overload due to aortic constriction). To assess functional consequences of selective down-regulation of endogenous RGS2, we identified targeting sequences for effective RGS2 RNA interference and used lipid-based transfection to achieve uptake of fluorescently labeled RGS2 small interfering RNA in >90% of neonatal and adult ventricular myocytes. Endogenous RGS2 expression was dose-dependently suppressed (up to 90%) with no major change in RGS3-RGS5. RGS2 knockdown increased phenylephrine- and endothelin-1-induced phospholipase Cbeta stimulation in both cell types and exacerbated the hypertrophic effect (increase in cell size and radiolabeled protein) in neonatal myocytes, with no major change in G(q/11)-mediated ERK1/2, p38, or JNK activation. Taken together, this study demonstrates that endogenous RGS2 exerts functionally important inhibitory restraint on G(q/11)-mediated phospholipase Cbeta activation and hypertrophy in ventricular myocytes. Our findings point toward a potential pathophysiological role of loss of fine tuning due to selective RGS2 down-regulation in G(q/11)-mediated remodeling. Furthermore, this study shows the feasibility of effective RNA interference in cardiomyocytes using lipid-based small interfering RNA transfection.