Kidney replacement and conservative therapies in rhabdomyolysis: a retrospective analysis.

BACKGROUND: Toxic renal effects of myoglobin following rhabdomyolysis can cause acute kidney injury (AKI) with the necessity of kidney replacement therapy (KRT). Fast elimination of myoglobin seems notable to save kidney function and intensify kidney repair. Clinical data regarding efficacy of KRT in critical care patients with rhabdomyolysis and AKI are limited. This retrospective analysis aimed to identify differences between conservative therapy and different modalities of KRT regarding myoglobin elimination and clinical outcome. METHODS: This systematic, retrospective, single-center study analyzed 328 critical care patients with rhabdomyolysis (myoglobin > 1000 µg/l). Median reduction rate of myoglobin after starting KRT was calculated and compared for different modalities. Multivariate logistic regression models were established to identify potential confounder on hospital mortality. Filter lifetime of the various extracorporeal circuits was analyzed by Kaplan-Meier curves. RESULTS: From 328 included patients 171 required KRT. Health condition at admission of this group was more critical compared to patient with conservative therapy. Myoglobin reduction rate did not differ between the groups (KRT 49% [30.8%; 72.2%] vs. conservative treatment (CT) 61% [38.5%; 73.5%]; p = 0.082). Comparison between various extracorporeal procedures concerning mortality showed no significant differences. Hospital mortality was 55.6% among patients with KRT and 18.5% with CT (p < 0.001). Multivariate logistic regression model identified requirement for KRT (OR: 2.163; CI: 1.061-4.407); p = 0.034) and the SOFA Score (OR: 1.111; CI: 1.004-1.228; p = 0.041) as independent predictive factors for hospital mortality. When comparing specific KRT using multivariate regression, no benefit was demonstrated for any treatment modality. Life span of the extracorporeal circuit was shorter with CVVH compared to that of others (log-Rank p = 0.017). CONCLUSIONS: This study emphasizes that AKI requiring KRT following rhabdomyolysis is accompanied by high mortality rate. Differences in myoglobin reduction rate between various KRTs could not be confirmed, but CVVH was associated with reduced filter lifetime compared to other KRTs, which enable myoglobin elimination, too.

Extended genomic HLA typing identifies previously unrecognized mismatches in living kidney transplantation.

Introduction: Antibody mediated rejection (ABMR) is the most common cause of long-term allograft loss in kidney transplantation (KT). Therefore, a low human leukocyte antigen (HLA) mismatch (MM) load is favorable for KT outcomes. Hitherto, serological or low-resolution molecular HLA typing have been adapted in parallel. Here, we aimed to identify previously missed HLA mismatches and corresponding antibodies by high resolution HLA genotyping in a living-donor KT cohort. Methods: 103 donor/recipient pairs transplanted at the University of Leipzig Medical Center between 1998 and 2018 were re-typed using next generation sequencing (NGS) of the HLA loci -A, -B, -C, -DRB1, -DRB345, -DQA1, -DQB1, -DPA1, and -DPB1. Based on these data, we compiled HLA MM counts for each pair and comparatively evaluated genomic HLA-typing with pre-transplant obtained serological/low-resolution HLA (=one-field) typing results. NGS HLA typing (=two-field) data was further used for reclassification of de novo HLA antibodies as "donor-specific". Results: By two-field HLA re-typing, we were able to identify additional MM in 64.1% (n=66) of cases for HLA loci -A, -B, -C, -DRB1 and -DQB1 that were not observed by one-field HLA typing. In patients with biopsy proven ABMR, two-field calculated MM count was significantly higher than by one-field HLA typing. For additional typed HLA loci -DRB345, -DQA1, -DPA1, and -DPB1 we observed 2, 26, 3, and 23 MM, respectively. In total, 37.3% (69/185) of de novo donor specific antibodies (DSA) formation was directed against these loci (DRB345 ➔ n=33, DQA1 ➔ n=33, DPA1 ➔ n=1, DPB1 ➔ n=10). Conclusion: Our results indicate that two-field HLA typing is feasible and provides significantly more sensitive HLA MM recognition in living-donor KT. Furthermore, accurate HLA typing plays an important role in graft management as it can improve discrimination between donor and non-donor HLA directed cellular and humoral alloreactivity in the long range. The inclusion of additional HLA loci against which antibodies can be readily detected, HLA-DRB345, -DQA1, -DQB1, -DPA1, and -DPB1, will allow a more precise virtual crossmatch and better prediction of potential DSA. Furthermore, in living KT, two-field HLA typing could contribute to the selection of the immunologically most suitable donors.

The diagnostic value of native kidney biopsy in low grade, subnephrotic, and nephrotic range proteinuria: A retrospective cohort study.

BACKGROUND: In nephrotic range proteinuria of adult-onset, kidney biopsy is the diagnostic gold standard in determining the underlying cause of disease. However, in low grade or subnephrotic proteinuria the diagnostic value of kidney biopsy as first-line diagnostics is less well established. METHODS: We conducted a retrospective analysis of all native kidney biopsies at our institution (n = 639) between 01/2012 and 05/2021 for comparison of histological diagnoses and clinical outcomes stratified by amount of proteinuria at the time of kidney biopsy: A: <300mg/g creatinine (low grade), B: 300-3500mg/g creatinine (subnephrotic), C >3500mg/g creatinine (nephrotic). RESULTS: Nephrotic range proteinuria was associated with the highest frequency (49.3%) of primary glomerulopathies followed by subnephrotic (34.4%) and low grade proteinuria (37.7%). However, within the subnephrotic group, the amount of proteinuria at kidney biopsy was linearly associated with renal and overall survival (HR 1.05 per Δ100mg protein/g creatinine (95% CI: 1.02-1.09, p = 0.001)) independent of present histological diagnoses and erythrocyturia. CONCLUSION: Frequency of primary glomerulopathies supports to perform kidney biopsy in patients with subnephrotic proteinuria. These patients have a substantial risk of ESKD and death upon follow-up. Therefore, diagnostic accuracy including histopathology is essential to guide personalized treatment and avert detrimental courses.

Myocardial Infarction after Long-Term Treatment with a Tyrosine Kinase Inhibitor (TKI) with Anti-VEGF Receptor Activity.

TKIs including anti-VEGF receptor activity have been approved for the treatment of patients with radioiodine resistant thyroid carcinomas. For lenvatinib arterial thromboembolic events are listed as adverse events of special interest with lenvatinib. In the phase III study, arterial thromboembolic events were reported in 3% of lenvatinib-treated patients and 1% in the placebo group. Most of the patients had predisposing factors. Only one myocardial infarct was reported in the lenvatinib phase III study. We report a 73-year-old female patient with metastatic thyroid papillary carcinoma who was treated with total thyroidectomy. The operation was followed by four radioiodine therapies over a period of 6 years. At 6 years she developed lung metastasis without radioiodine uptake, one solitary liver metastasis and one solitary right renal metastasis. One year after the first diagnosis of radioiodine resistant lung metastasis the lung metastasis showed progression according to RECIST criteria. This treatment was resulting in prolonged partial response with disappearance of a hepatic and renal metastasis. A myocardial infarction occurred after 39 months of lenvatinib treatment resulting in implantation of 3 stents and a two chamber pacemaker. The treatment was discontinued. Except for well controlled hypertension there were neither predisposing diseases like diabetes nor symptoms of cardiac ischemia on exertion. However, the family history for cardiovascular diseases was positive for cardiac infarction reported for one brother. Another brother was treated for hypertension and the patient's mother suffered from a cerebral infarction at the age of 60. While only one myocardial infarct was reported in the lenvatinib phase III study with 392 patients this case suggests that long-term treatment with lenvatinib may be associated with an increased risk for myocardial infarct also in patients with no predisposing diseases except well controlled hypertension and positive family history for cardiovascular diseases.

Deleterious Impact of a Novel CFH Splice Site Variant in Atypical Hemolytic Uremic Syndrome.

Atypical hemolytic uremic syndrome (aHUS) is a heterogeneous disorder characterized by microangiopathic hemolytic anemia (MAHA), thrombocytopenia, and acute kidney injury (AKI). In about 50% of cases, pathogenic variants in genes involved in the innate immune response including complement factors complement factor H (CFH), CFI, CFB, C3, and membrane co-factor protein (MCP/CD46) put patients at risk for uncontrolled activation of the alternative complement pathway. As aHUS is characterized by incomplete penetrance and presence of additional triggers for disease manifestation, genetic variant interpretation is challenging and streamlined functional variant evaluation is urgently needed. Here, we report the case of a 27-year-old female without previous medical and family history who presented with confusion, petechial bleeding, and anuric AKI. Kidney biopsy revealed glomerular thrombotic microangiopathy (TMA). Targeted next generation sequencing identified a paternally transmitted novel heterozygous splice site variant in the CFH gene [c.3134-2A>G; p.Asp1045_Thr1053del] which resulted in a partial in-frame deletion of exon 20 transcript as determined by cDNA analysis. On the protein level, the concomitant loss of 9 amino acids in the short consensus repeat (SCR) domains 17 and 18 of CFH includes a highly conserved cysteine residue, which is assumed to be essential for proper structural folding and protein function. Treatment with steroids, plasmapheresis, and the complement inhibitor eculizumab led to complete hematological and clinical remission after several months and stable renal function up to 6 years later. In conclusion, genetic investigation for pathogenic variants and evaluation of their functional impact, in particular in the case of splice site variants, is clinically relevant and enables not only better molecular understanding but helps to guide therapy with complement inhibitors.

Value of renal gene panel diagnostics in adults waiting for kidney transplantation due to undetermined end-stage renal disease.

End-stage renal disease (ESRD) of undetermined etiology is highly prevalent and constitutes a significant clinical challenge, particularly in the context of kidney transplantation (KT). Despite the identification of numerous rare hereditary nephropathies over the last few decades, patients with undetermined ESRD are not being systematically investigated for rare genetic causes in clinical practice. To address this, we utilized mutation analysis in patients on the kidney transplant waitlist and scrutinized underlying renal diagnoses of 142 patients in a single center KT-waitlist. This cohort was stratified into 85 cases of determined and 57 cases of undetermined ESRD. The latter patients were analyzed by a renal gene panel for mutations in 209 genes associated with ESRD. The most likely genetic diagnoses in 12% of the tested individuals with undetermined ESRD were established. All of these patients showed mutations in genes encoding components of the glomerular filtration barrier. Taken together, hereditary nephropathies, including autosomal dominant polycystic kidney disease, were identified in 35 of the 142 patients of the waitlist cohort. By significantly increasing the proportion of hereditary diagnoses from 29 to 35 patients, the rate of undetermined ESRD significantly decreased from 57 to 51 patients. This study demonstrates the beneficial use of genetic diagnostics in significantly unraveling undetermined ESRD cases prior to KT. Thus, in the absence of renal histology or the presence of unspecific histological conditions, such as hypertensive nephrosclerosis, focal segmental glomerulosclerosis or thrombotic microangiopathy, genetic analysis may provide a robust and specific renal diagnosis and allow for optimizing pre- and post-KT management.

Anti VEGF-TKI Treatment and New Renal Adverse Events Not Reported in Phase III Trials.

Cabozantinib and lenvatinib have been approved for the treatment of progressive medullary thyroid cancer and radioiodine-resistant thyroid cancer, respectively. Both phase III trials of cabozantinib and lenvatinib reported that renal adverse events (AEs) rarely occurred. The cabozantinib phase III study reported no AEs related to renal toxicity. In the lenvatinib phase III trial grade 3 (CTCAE), proteinuria (urinary protein ≥3.5 g/24 h) was found in 10.0% of the lenvatinib and 0.0% of the placebo patients. We report a 23-year-old patient with metastatic medullary thyroid cancer who was enrolled in the phase III trial, comparing cabozantinib to placebo and a 67-year-old patient with metastatic, papillary thyroid carcinoma who was undergoing treatment with lenvatinib during his enrollment in the phase III trial. The first patient had a normal kidney function initially, but developed end-stage chronic kidney disease unexpectedly on cabozantinib and additional zoledronate infusion. Whereas the second patient suffered from a dramatic aggravation of his known mild chronic renal insufficiency (KDOQI stage 2) due to long standing hypertension and atherosclerosis during the treatment with lenvatinib. These severe AEs due to anti-VEGF tyrosine kinase inhibitor treatment were unknown so far. In conclusion, these 2 cases argue for increased awareness for the possibility of renal failure as a consequence of anti-VEFG treatment. Predisposing conditions like known mild chronic renal insufficiency with only mild proteinuria and with atherosclerosis or precipitating co-medications like zoledronate infusion need to be accounted for to prevent these severe AEs.

Early Flow Disturbances of Tunnelled Haemodialysis Catheters and Topographic Landmarks in Chest X-Ray.

BACKGROUND/AIMS: The position of the tip of tunnelled haemodialysis (HD) catheters (THC) might influence flow characteristics during HD. In chest X-ray (CXR), carina-related landmarks may be practicable to verify the THC position, and tip-carina distance (TCD) might be useful to predict early-flow dysfunctions. METHODS: In this single-centre, retrospective study, the TCD and the angle between the distal catheter and the body vertical axis (tip-body vertical-angle [TVA]) was measured in 115 THC by post-procedure CXR with 2 investigators. The parameters were proved to be feasible by interrater-reliability and correlated with the incidence of flow-dysfunction within 10 days after insertion. RESULTS: Steep-aligned (TVA <40°, p < 0.01) and deep-ending catheters (TCD: right-sighted >1.5 cm or left-sighted >4.5 cm below the carina; p < 0.01) showed a significantly less dysfunction with a good interrater-reliability (R[TVA] = 0.8, R[TCD] = 0.9). CONCLUSIONS: Carina-related landmarks in CXR might be helpful to predict early-flow dysfunctions. However, randomized studies will be necessary to confirm this in fluoroscopic-guided placement during the insertion of THC.

The Pituitary-Thyroid Axis and Prolactin Secretion in Hemodialysis Patients in Two Endemic Regions of Eastern Germany.

INTRODUCTION: Endocrine disorders of the pituitary axes are frequent in patients with hemodialysis (CKD5D). The aim of this multicenter study (Leipzig (L), Quedlinburg and Blankenburg in the Harz region (Hz)) in CKD5D patients was to evaluate influences of CKD5D related factors, morphological and biochemical parameters, and serum iodine and prolactin concentrations on the pituitary-thyroid axis. PATIENTS AND METHODS: 170 patients (L n=58; Hz n=112) were included in this prospective, non-interventional, cross-sectional study. Mann-Whitney-U-test and bivariate correlation analyses with Spearman-Rho test (r correlation coefficient) were used in statistical analysis. RESULTS: TSH was higher in patients with prolactin concentrations>370 mIU/l (p=0.013), in patients with high flux membranes (p=0.0013) and in patients with longer dialysis vintage (p=0.04). Median iodine serum concentrations were slightly elevated in the Leipzig cohort (p=0.001) and correlated with fT4 (p<0.001, r=0.43) and albumin (p=0.001, r=0.245) but not with morphological signs. Albumin was correlated with fT3 (p<0.001, r=0.339) and fT4 (p<0.001, r=0.421). Prolactin was correlated with residual excretion rate (p=0.001, r=- 0.303) and thyroid volume (p=0.027, r=0.217). CONCLUSIONS: In the assessment of the thyroid status in CKD5D patients, the synopsis of the clinical and nutritional status, comorbidities, ultrasound of the thyroid gland and laboratory results is necessary for further intervention with hormone replacement. Standardized reference values of the pituitary-thyroid axis should be critically evaluated and are still lacking in CKD5D.

Dual RAAS Blockade with Aliskiren in Patients with Severely Impaired Chronic Kidney Disease.

Dual renin-angiotensin-aldosterone blockade (dRAASb) is purposed in the prevention of the cardiorenal syndrome (CRS). However, all attempts with dRAASb even in patients with moderate impaired chronic kidney disease (CKD) were terminated due to the typical severe adverse events (SAE), e. g., hyperkalemia and rise of serum creatinine. The aim of our study with the direct renin inhibitor aliskiren was to evaluate the effect of dRAASb with a washout phase in patients with severely advanced CKD. We have studied 45 patients (G3b to 4, A2 and >A3; median glomerular filtration rate (GFR) CKD-EPI 31 (23-40) ml/min per 1.73 m² BSA (body surface area), albumin-creatinine-ratio in urine (UACR) (0.413 (0.164 to 1.39) g/g) and proteinuria (0.5 (0.2 to 0.9) g/l) before, with and without aliskiren (150 respectively 300 mg per day) added to an angiotensin-converting enzyme inhibitor (ACEi) or an AT1-receptor blocker (ARB) over 4 ½ years. The dRAASb with aliskiren showed a significant decrease of proteinuria (0.5 to 0.38 g/l), especially in patients with an UACR≥350 mg/g and in the subgroup analysis e. g., in patients with diabetes, but proteinuria increased in the washout phase again. The blood pressure (130/80 mm Hg), serum potassium (4.9 to 5.0 mmol/l) and GFR remained nearly constant (31 to 29.5 ml/min per 1.73 m2 BSA). A more than 30% increase in serum creatinine was associated with an UACR>300 mg/g. The dRAASb has beneficial effects on proteinuria and is safe in patients with severely advanced CKD. However, in patients with high UACR (>300 mg/g) raise of creatinine and potassium have to be controlled.

Effective immunosuppressive management with belatacept and eculizumab in post-transplant aHUS due to a homozygous deletion of CFHR1/CFHR3 and the presence of CFH antibodies.

Atypical haemolytic uraemic syndrome (aHUS) may clinically present as acute renal graft failure resulting from excessive activation of the complement cascade. While mutations of complement-encoding genes predispose for aHUS, it is generally thought to require an additional insult (e.g. drugs) to trigger and manifest the full-blown clinical syndrome. Calcineurin inhibitors (CNIs) used for immunosuppression act as potential triggers, especially in the post-transplantation setting. Therefore, CNI-free immunosuppressive regimens may be beneficial. We report on a 58-year-old woman who developed aHUS with acute graft failure within 20 days after renal transplantation. Genetic investigation revealed a homozygous deletion of the CFH-related 1 (CFHR1) and CFHR3 genes in addition to the presence of autoantibodies against complement factor H (CFH). The patient was treated with plasmapheresis and administration of the complement component 5 (C5) antibody eculizumab, and her immunosuppressive regimen was switched from CNI (tacrolimus) to the cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitor belatacept. Renal graft function recovered and stabilized over an 18-month follow-up period. We describe the successful management of post-transplant aHUS using a CNI-free immunosuppressive regimen based on eculizumab and belatacept. Ideally, adequate molecular diagnostics, performed prior to transplantation, can identify relevant genetic risk factors for graft failure and help to select patients for individualized immunosuppressive regimens.

[Clinical Course of an Early Childhood-Onset Granulomatosis with Polyangiitis]. / Klinischer Verlauf einer Granulomatose mit Polyangiitis mit frühem Beginn in der Kindheit.

History A 26-year-old male patient presented with an eight-week history of unspecific symptoms such as weight loss and fever. Besides, he also suffered from haemoptysis, cough, and arthralgia. Since the age of twelve years, the patient has been treated for Wegner's granulomatosis. At the age of 20 years he received a kidney transplant which failed only four years later. Investigations The relapse we clinically suspected was confirmed by CT scan showing bilateral pulmonary manifestations. Moreover, we found highly positive antibodies against proteinase 3. Treatment and course After an induction therapy using Glucocorticoids and Rituximab, accompanied by plasmapheresis, the patient's clinical condition showed a marked improvement. We were able to discharge him continuing the treatment in an outpatient setting. Conclusion Childhood-onset GPA is a life-threatening disease and often characterized by recurring relapses as well as a significantly reduced quality of life for the patient.

Influence of Erythropoiesis-Stimulating Agents on HbA1c and Fructosamine in Patients with Haemodialysis.

HbA1c is the most accepted laboratory parameter for the long term observation of glucose control. There is still much of a debate about the use of HbA1c as a metabolic indicator in diabetic patients (DM) on haemodialysis (HD) and erythropoiesis-stimulating agent (ESA) therapy because of the altered erythrocyte turn over in patients with chronic kidney disease and haemodialysis (CKD5D). In 102 CKD5 patients with and without diabetes mellitus, we examined the dose dependent variability in HbA1c and fructosamine levels under haemodialysis and treated with epoetin α (n=48) and a new generation agent with continuous stimulation of methoxy polyethylene glycol epoetin beta (C.E.R.A.; n=54). HbA1c levels were affected by therapy with ESA treatments. ESA dose was inversely correlated with HbA1c and an escalation of 10.000 IU per week induced an estimated decrease of HbA1c of 0.6 percent. In addition, the increase of reticulocyte number as a marker for erythropoiesis was significantly inversely correlated with the increase of ΔHbA1c. ESA treatments had no such effect on the alternative metabolic parameter fructosamine. When compared, both therapeutic agents had comparable success in attaining haemoglobin (Hb) target values. C.E.R.A. showed better correlation and was more effective over a longer dose interval. Our results show that HbA1c levels in patients should be carefully interpreted based on interfering factors. Nevertheless, HbA1c is currently the most consistent parameter for use ascertaining metabolic status of patients suffering from diabetes mellitus.

Diagnosing FSGS without kidney biopsy - a novel INF2-mutation in a family with ESRD of unknown origin.

BACKGROUND: Patients on renal replacement therapy are often unaware of their underlying condition and hence suffer from so-called end-stage renal disease (ESRD) of unknown origin. However, an exact diagnosis is not only important for better estimating the prognosis, but also when preparing for kidney transplantation. Whilst patients with FSGS without a confirmed genetic cause have a high recurrence rate in the transplanted organ, patients with a mutation generally exhibit no recurrence and have a good prognosis. Furthermore, renal biopsy, which may be helpful for differential diagnosis, is usually contraindicated in end-stage kidneys. We here present the case of familial ESRD of unknown origin, which could be resolved by targeted genetic testing prior to planning of kidney transplantation. CASE PRESENTATION: A 32-year-old female with ESRD and nephrotic range proteinuria was admitted to our clinic. Family-history revealed that both mother and maternal grandmother had ESRD of unknown origin. As renal biopsy was impossible due to atrophic kidneys, we performed mutation analysis of genes known for dominant forms of FSGS and found a novel heterozygous mutation of INF2 (c.485 T > C, p.Leu162Pro). The same mutation could be detected in the index patient's mother (ESRD at age 50) and three brothers with normal serum-creatinine but mid or low range proteinuria. CONCLUSIONS: Genetic testing is warranted in families with ESRD of unknown origin and may provide a robust diagnosis even without kidney biopsy. It will help detecting relatives at risk who have to be excluded from potential kidney donation and who may benefit from timely initiation of protective measures in order to slow down disease progression.

Secreted frizzled-related protein 4 predicts progression of autosomal dominant polycystic kidney disease.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is a common autosomal dominant condition associated with renal cysts and development of renal failure. With the availability of potential therapies, one major obstacle remains the lack of readily available parameters that identify patients at risk for disease progression and/or determine the efficacy of therapeutic interventions within short observation periods. Increased total kidney volume (TKV) correlates with disease progression, but it remains unknown how accurate this parameter can predict disease progression at early stages. METHODS: To identify additional parameters that help to stratify ADPKD patients, we measured secreted frizzled-related protein 4 (sFRP4) serum concentrations at baseline and over the course of 18 months in 429 ADPKD patients. RESULTS: Serum creatinine and sFRP4 as well as TKV increased over time, and were significantly different from baseline values within 1 year. CONCLUSION: Elevated sFRP4 levels at baseline predicted a more rapid decline of renal function at 2, 3 and 5 years suggesting that sFRP4 serum levels may provide additional information to identify ADPKD patients at risk for rapid disease progression.

Autochthonous Dobrava-Belgrade virus infection in Eastern Germany.

A 21-year-old male patient from Borna, Saxony, in Eastern Germany, suffered from acute kidney injury (AKI) and symptoms typical for a hantavirus infection. These symptoms included nausea, vomiting, abdominal pain, diarrhea, and acute renal failure. Serological investigations by indirect IgM and IgG in-house ELISAs, commercial immunofluorescence and line assays, as well as chemiluminescence focus reduction neutralization assay confirmed an acute Dobrava-Belgrade virus (DOBV) infection of the patient. Serological and RT-PCR analyses of striped field mouse (Apodemus agrarius) trapped in a neighboring region of the residence of the patient identified an infection by DOBV, genotype Kurkino. This is the first report of an autochthonous DOBV infection in a German patient living far from the known endemic region in the north of the country. This finding has implications for the awareness of physicians in areas which are not recognized as hantavirus endemic regions but where the reservoir host of the virus is present.

Genome-wide linkage analysis is a powerful prenatal diagnostic tool in families with unknown genetic defects.

Genome-wide linkage analysis is an established tool to map inherited diseases. To our knowledge it has not been used in prenatal diagnostics of any genetic disorder. We present a family with a severe recessive mental retardation syndrome, where the mother wished pregnancy termination to avoid delivering another affected child. By genome-wide scanning using the Affymetrix (Santa Clara, CA, USA) 10k chip we were able to establish the disease haplotype. Without knowing the exact genetic defect, we excluded the condition in the fetus. The woman finally gave birth to a healthy baby. We suggest that genome-wide linkage analysis--based on either SNP mapping or full-genome sequencing--is a very useful tool in prenatal diagnostics of diseases.

Pilot study of extracorporeal removal of soluble fms-like tyrosine kinase 1 in preeclampsia.

BACKGROUND: Targeted therapies to stabilize the clinical manifestations and prolong pregnancy in preeclampsia do not exist. Soluble fms-like tyrosine kinase 1 (sFlt-1), an alternatively spliced variant of the vascular endothelial growth factor receptor 1, induces a preeclampsia-like phenotype in experimental models and circulates at elevated levels in human preeclampsia. Removing sFlt-1 may benefit women with very preterm (<32 weeks) preeclampsia. METHODS AND RESULTS: We first show that negatively charged dextran sulfate cellulose columns adsorb sFlt-1 in vitro. In 5 women with very preterm preeclampsia and elevated circulating sFlt-1 levels, we next demonstrate that a single dextran sulfate cellulose apheresis treatment reduces circulating sFlt-1 levels in a dose-dependent fashion. Finally, we performed multiple apheresis treatments in 3 additional women with very preterm (gestational age at admission 28, 30, and 27+4 weeks) preeclampsia and elevated circulating sFlt-1 levels. Dextran sulfate apheresis lowered circulating sFlt-1, reduced proteinuria, and stabilized blood pressure without apparent adverse events to mother and fetus. Pregnancy lasted for 15 and 19 days in women treated twice and 23 days in a woman treated 4 times. In each, there was evidence of fetal growth. CONCLUSIONS: This pilot study supports the hypothesis that extracorporeal apheresis can lower circulating sFlt-1 in very preterm preeclampsia. Further studies are warranted to determine whether this intervention safely and effectively prolongs pregnancy and improves maternal and fetal outcomes in this setting.

Faulty initiation of proteoglycan synthesis causes cardiac and joint defects.

Proteoglycans are a major component of extracellular matrix and contribute to normal embryonic and postnatal development by ensuring tissue stability and signaling functions. We studied five patients with recessive joint dislocations and congenital heart defects, including bicuspid aortic valve (BAV) and aortic root dilatation. We identified linkage to chromosome 11 and detected a mutation (c.830G>A, p.Arg277Gln) in B3GAT3, the gene coding for glucuronosyltransferase-I (GlcAT-I). The enzyme catalyzes an initial step in the synthesis of glycosaminoglycan side chains of proteoglycans. Patients' cells as well as recombinant mutant protein showed reduced glucuronyltransferase activity. Patient fibroblasts demonstrated decreased levels of dermatan sulfate, chondroitin sulfate, and heparan sulfate proteoglycans, indicating that the defect in linker synthesis affected all three lines of O-glycanated proteoglycans. Further studies demonstrated that GlcAT-I resides in the cis and cis-medial Golgi apparatus and is expressed in the affected tissues, i.e., heart, aorta, and bone. The study shows that reduced GlcAT-I activity impairs skeletal as well as heart development and results in variable combinations of heart malformations, including mitral valve prolapse, ventricular septal defect, and bicuspid aortic valve. The described family constitutes a syndrome characterized by heart defects and joint dislocations resulting from altered initiation of proteoglycan synthesis (Larsen-like syndrome, B3GAT3 type).