Subclinical Hypothyroidism is Not Associated with Femoral Osteoporosis in Individuals Aged 50 Years or Older.

BACKGROUND: Thyroid dysfunction and osteoporosis are conditions strongly associated with aging, and the prevalence of both conditions is expected to increase in the coming decades. Thyroid hormones regulate bone metabolism, and the role of subclinical hypothyroidism on bone mineral density (BMD) is still controversial. Hence, this study aims to assess the association of subclinical hypothyroidism with femoral osteopenia and osteoporosis in individuals aged 50 years or older. METHODOLOGY: This retrospective cohort study was carried out with 864 outpatients having at least one result for TSH levels before the first record of dual-energy X-ray absorptiometry (DXA). The primary endpoints were osteopenia (-2.5 standard deviation (SD)

Eosinophil granule major basic protein 1 deposition in eosinophilic esophagitis correlates with symptoms independent of eosinophil counts.

In patients with eosinophilic esophagitis (EoE), symptoms often do not correlate with peak eosinophil counts (PEC) determined on histopathological examination of biopsy specimens. This may be because eosinophils degranulate during active disease and lose their morphological identity as intact cells and, therefore, are not enumerated on microscopic examination. Eosinophil granule proteins that are released into tissues with degranulation, including major basic protein 1 (eMBP1), likely contribute to disease pathogenesis and, therefore, may correlate with symptoms better than PEC. We sought to determine whether symptoms in patients with EoE more closely relate to eosinophil granule protein deposition than to eosinophil enumeration, especially in patients with fewer than 15 eosinophils per high power field (HPF). Esophageal biopsy specimens from 34 patients diagnosed with EoE were obtained for histopathological examination and for evaluation of eMBP1 staining by indirect immunofluorescence. PEC by histopathology were compared to extracellular eMBP1 grades by immunostaining. PEC and eMBP1 grades also were analyzed for their relationship to symptoms and clinical course. Biopsy specimens from 19 of the 34 patients had fewer than 15 PEC on histopathological examination, and the other 15 patients had 15 or greater PEC. Positive eMBP1 immunostaining was found in all symptomatic patients. EoE symptoms were related to eMBP1 immunostaining grades (p = 0.0001), but not PEC (P = 0.14). Eosinophil granule protein deposition, specifically eMBP1, is increased in esophageal biopsy specimens from symptomatic patients with EoE and may be a marker of disease activity, including patients with EoE who have 'resolved' disease.

Effects of comprehensive medication review on opioid overuse among medicare beneficiaries.

Objectives: This study examined the effects of the comprehensive medication review of Medicare medication therapy management programs on opioid overuse among Medicare beneficiaries. Methods: This retrospective study analyzed Medicare data from 2016 to 2017. The intervention group included Medicare beneficiaries who newly received comprehensive medication review in 2017; the control group referred to patients who met the general eligible criteria for the medication therapy management program but did not enroll in 2016 or 2017. Propensity score matching was performed to increase characteristic compatibility between the intervention and control groups. Three measures of opioid overuse were analyzed: use of opioids at a high dosage, use of opioids from multiple providers, and concurrent use of opioids and benzodiazepines. The effects of comprehensive medication review on opioid overuse were analyzed with a multivariate logistic regression with an interaction term between the receipt of comprehensive medication review and the year 2017. Key Findings: The proportion of concurrent use of opioids and benzodiazepines declined at a greater rate among the recipients (2.21%) than non-recipients (1.55%) of the comprehensive medication review. In the adjusted analysis, the odds ratio of no concurrent use of opioids and benzodiazepines was 5% higher (1.05; 95% confidence interval = 1.02-1.09) among recipients than non-recipients. These significant findings were not found for the other two measures of opioid overuse. Conclusions: Comprehensive medication review is associated with reduced concurrent use of opioids and benzodiazepines among Medicare beneficiaries. Such service should be incorporated into the current approaches for addressing the opioid epidemic.

Incarcerated Ink: A Case of Mycobacterium chelonae.

A 30-year-old African American male presented with pain and swelling of the right foot one month after receiving a tattoo on this foot in prison. During his admission for presumed cellulitis, he developed a rash on his contralateral (left) leg, which had been tattooed 10 months prior. A biopsy of the contralateral (left) leg showed acute, chronic, and granulomatous inflammation with a differential diagnosis including infection. His overall condition and both legs worsened, prompting biopsy and tissue culture of the right ankle and foot. Pathology of the right foot showed a granulomatous reaction. Culture grew Mycobacterium chelonae. This case highlights the importance of considering infectious etiologies for rashes appearing within tattoos and represents the importance of a full investigation to obtain the correct diagnosis.

Cytokine gene polymorphisms and Alzheimer's disease in Brazil.

BACKGROUND: Single-nucleotide polymorphisms in genes encoding immunological mediators can affect the biological activity of these molecules by regulating transcription, translation, or secretion, modulating the genetic risk of inflammatory damage in Alzheimer's disease (AD). Nonetheless, the Brazilian contingent is highly admixed, and few association trials performed herein with AD patients have considered genetic ancestry estimates as co-variables when investigating markers for this complex trait. METHODS: We analyzed polymorphisms in 10 inflammatory genes and compared the genotype distribution across outpatients with late-onset AD and noncognitively impaired subjects from Midwest Brazil under a strict criterion, and controlling for ancestry heritage and ApoE genotype. RESULTS: Our findings show an almost 40% lower chance of AD (p = 0.004) among homozygotes of the IL10 -1082A allele (rs1800896). Dichotomization to ApoE and mean ancestry levels did not affect protection, except among those with greater European or minor African heritage. CONCLUSION: The IL10 locus seems to affect the onset of AD in a context sensitive to the genetic ancestry of Brazilian older adults.

Amerindian genetic ancestry protects against Alzheimer's disease.

BACKGROUND: Alzheimer's disease (AD) is the most common form of dementia worldwide, and bears remarkable evidence for a differential prevalence among continental populations. In this scenario, estimating ancestry proportions in recently admixed populations is a strategy that can help increasing knowledge about the genetic structure of this complex trait. AIM/METHODS: Our purpose was to assess mean ancestry estimates for the three main parental contributors to the Brazilian contingent (European, African and Amerindian) using a panel of 12 ancestry informative markers. Outpatients with the late-onset form of AD (n = 120) were compared for ancestry levels with non-cognitively impaired subjects (n = 412) in the Midwest Brazil, controlling for classic clinical, social and anthropometric risk factors. RESULTS: Our findings show a 3-fold greater genetic Amerindian content among control subjects compared to AD patients (p < 0.001). CONCLUSION: Our results suggest that the allelic architecture of Native Americans can confer protection against the onset of the disease.

Usual dietary intake and cardiovascular risk factors in older Brazilian women.

AIM: To evaluate habitual macronutrient intake and its association with common cardiovascular risk factors in Brazilian elderly women. METHODS: Analytical cross-sectional study with 293 subjects. Carbohydrate, protein and lipid intakes were determined based on a non-consecutive three-day dietary record. The following conditions were evaluated: dyslipidemia, systemic arterial hypertension, and type 2 diabetes. RESULTS: Anthropometric, clinical and biochemical data revealed an elevated prevalence of classic cardiovascular risk factors in the sample. Higher energy intake from omega-3 fatty acid was associated with elevated levels of high-density lipoprotein cholesterol (p<0.05), whereas a diet pattern with a relatively lower energy content from monounsaturated fatty acids was associated with the presence of type 2 diabetes (p<0.05). CONCLUSIONS: Results corroborate experimental reports and contribute by suggesting that the usual diet, independently of supplementation, may be valuable in promoting health and preventing chronic diseases of aging.

Lessons from genome-wide association studies findings in Alzheimer's disease.

Alzheimer's disease (AD) is the most common neurodegenerative disorder with a complex genetic background. Recent genome-wide association studies (GWAS) have placed important new contributors into the genetic framework of early- and late-onset forms of this dementia. Besides confirming the major role of classic allelic variants (e.g. apolipoprotein E) in the development of AD, GWAS have thus far implicated over 20 single nucleotide polymorphisms in AD. In this review, we summarize the findings of 16 AD-based GWAS performed to date whose public registries are available at the National Human Genome Research Institute, with an emphasis on understanding whether the polymorphic markers under consideration support functional implications to the pathophysiological role of the major genetic risk factors unraveled by GWAS.

Long-term resistance training is associated with reduced circulating levels of IL-6, IFN-γ and TNF-α in elderly women.

OBJECTIVE: The increase in inflammatory activity associated with aging is a characteristic of chronic disease processes that accounts for most of the mortality in the elderly. Resistance training (RT) has been shown to promote metabolic and functional benefits in this population. The objective of this study was to investigate the association between long-term RT and circulating levels of the proinflammatory mediators IL-6, TNF-α and IFN-γ in elderly women. METHODS: This cross-sectional study included 54 older outpatients divided into a group that underwent RT (n = 28) for an average of 8.6 ± 0.3 months and a sedentary group (n = 26). Measurements were taken only at the end of the intervention, and cytokine values were log-transformed. Dietary intake was controlled as a confounding factor. RESULTS: The RT group presented reduced levels of log10IFN-γ (approx. 45%; p = 0.003), log10IL-6 (approx. 30%; p = 0.002) and log10TNF-α (approx. 22%; p = 0.036). Total caloric intake and systolic arterial blood pressure were significantly lower in the RT group (p = 0.001 and p = 0.022, respectively). Pearson's product moment correlation test revealed a negative association between the fat-free mass (FFM) index and log-transformed IL-6 levels (p = 0.03; n = 54) and a trend towards significance for the correlation between the FFM index and log10IFN-γ (p = 0.05; n = 54). CONCLUSION: Long-term, moderate-intensity RT in elderly women is associated with lower circulating levels of cytokines that are potentially implicated in disorders associated with physical inactivity and aging.

Spectroscopic and Photophysical Investigation of Model Dipyrroles Common to Bilins: Exploring Natural Design for Steering Torsion to Divergent Functions.

Biliproteins are a unique class of photosynthetic proteins in their diverse, and at times, divergent biophysical function. The two contexts of photosynthetic light harvesting and photoreception demonstrate characteristically opposite criteria for success, with light harvesting demanding structurally-rigid chromophores which minimize excitation quenching, and photoreception requiring structural flexibility to enable conformational isomerization. The functional plasticity borne out in these two biological contexts is a consequence of the structural plasticity of the pigments utilized by biliproteins-linear tetrapyrroles, or bilins. In this work, the intrinsic flexibility of the bilin framework is investigated in a bottom-up fashion by reducing the active nuclear degrees of freedom through model dipyrrole subunits of the bilin core and terminus free of external protein interactions. Steady-state spectroscopy was carried out on the dipyrrole (DPY) and dipyrrinone (DPN) subunits free in solution to characterize their intrinsic spectroscopic properties including absorption strengths and nonradiative activity. Transient absorption (TA) spectroscopy was utilized to determine the mechanism and kinetics of nonradiative decay of the dipyrrole subunits, revealing dynamics dominated by rapid internal conversion with some Z→E isomerization observable in DPY. Computational analysis of the ground state conformational landscapes indicates enhanced complexity in the asymmetric terminal subunit, and the prediction was confirmed by heterogeneity of species and kinetics observed in TA. Taken together, the large oscillator strengths (f ∼ 0.6) of the dipyrrolic derivatives and chemically-efficient spectral tunability seen through the ∼100 nm difference in absorption spectra, validate Nature's "selection" of multi-pyrrole pigments for light capture applications. However, the rapid deactivation of the excited state via their natural torsional activity when free in solution would limit their effective biological function. Comparison with phytochrome and phycocyanin 645 crystal structures reveals binding motifs within the in vivo bilin environment that help to facilitate or inhibit specific inter-pyrrole twisting vital for protein operation.

Beneficial Roles of Cellulose Patch-Mediated Cell Therapy in Myocardial Infarction: A Preclinical Study.

Biological scaffolds have become an attractive approach for repairing the infarcted myocardium and have been shown to facilitate constructive remodeling in injured tissues. This study aimed to investigate the possible utilization of bacterial cellulose (BC) membrane patches containing cocultured cells to limit myocardial postinfarction pathology. Myocardial infarction (MI) was induced by ligating the left anterior descending coronary artery in 45 Wistar rats, and patches with or without cells were attached to the hearts. After one week, the animals underwent echocardiography to assess for ejection fraction and left ventricular end-diastolic and end-systolic volumes. Following patch formation, the cocultured cells retained viability of >90% over 14 days in culture. The patch was applied to the myocardial surface of the infarcted area after staying 14 days in culture. Interestingly, the BC membrane without cellular treatment showed higher preservation of cardiac dimensions; however, we did not observe improvement in the left ventricular ejection fraction of this group compared to coculture-treated membranes. Our results demonstrated an important role for BC in supporting cells known to produce cardioprotective soluble factors and may thus provide effective future therapeutic outcomes for patients suffering from ischemic heart disease.

The effects of intermittent stretching following a 4-week static stretching protocol: a randomized trial.

Stretching is performed in rehabilitation and sports conditioning programs. It is not known how often during a week stretching needs to be performed to maintain flexibility. Therefore, the purpose of this study was to determine the influence of intermittent stretching (i.e., 2-3 days/week) on hip range of motion (ROM) following a 4-week, daily stretching program. This study used a randomized, single-blind, test-retest design. Healthy adult subjects, age 18 to 50 years, were randomly assigned to 1 of 2 static stretching protocols: (a) standard protocol or (b) intermittent protocol. All subjects stretched their hamstrings daily for the first 4 weeks. The standard group discontinued all stretching after 4 weeks. The intermittent group continued to stretch 2 to 3 days per week for an additional 4 weeks. All subjects were measured for hip ROM weekly for the full 8 weeks. Thirty-two subjects completed the study (standard group = 14; intermittent group = 18, mean age 24.6 years). Mean hip ROM increased (p < 0.05) for both groups from before protocol (PRE) to Week 4 (standard group gain from 71.4 +/- 18.5 degrees to 90.6 +/- 20.5 degrees and intermittent group gain from 68.6 +/- 15.7 degrees to 89.1 +/- 16.8 degrees). During the final 4 weeks, mean hip ROM decreased (p < 0.05) for the standard group from 90.6 +/- 20.5 degrees to 83.9 +/- 20.3 degrees. Mean hip ROM for the intermittent group did not decrease during the final 4 weeks of the study (89.1 +/- 16.8 degrees to 93.2 +/- 14.9 degrees, p > 0.05). Intermittent stretching (i.e., 2 or 3 days/week) is sufficient to maintain ROM gains acquired from a prior static stretching program. Clinicians and trainers may educate their clients of the benefits of intermittent stretching to maintain flexibility.

Evidence for a contribution of the APOE (but not the ACE) gene to the sleep profile of non-demented elderly adults.

This study aims to investigate alleles of the human apolipoprotein E (APOE) and of the angiotensin-converting enzyme (ACE) genes as risk factors for poor quality of sleep in elderly individuals with no major cognitive decline. This cross-sectional, analytical study was conducted with 163 participants aged 75 years in average and 85% female. Sociodemographic, anthropometric and clinical data were gathered, and sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) and the Epworth scale, with patient followed for years prior to these evaluations to rule out onset of major mental disorders. Genotyping of classic polymorphic sites for the ApoE (rs429358 and rs7412) and the ACE (rs4646994) genes used peripheral DNA. A total of 63% of the subjects reported poor quality of sleep assessed by the PSQI whereas 54 (33%) reported daytime sleepiness through the Epworth scale. A significant correlation was observed between APOE and PSQI, with a greater frequency of the poor nighttime sleep quality phenotype among ε2 carriers, whereas no correlation was found among any of the sleep scores and the ACE genotypes. Thus, we suggest a correlation between APOE alleles and scale-assessed sleep quality scores in older adults, with no implications for ACE alleles, in a context devoid of cognitive impairment.

Successful treatment of recurrent Henoch-Schönlein purpura in a renal allograft with plasmapheresis.

Acute and severe cases of Henoch-Schönlein purpura (HSP) nephritis have been treated with plasmapheresis (PA) in both adults and children. It has been used either alone or with steroids, antiplatelets or cytoxic drugs. Generally, renal function has been shown to improve when PA is utilized. The role of PA in recurrent HSP after renal transplantation is unclear and has not been well described in the literature. We report a 29-year-old female with HSP who developed end-stage renal disease and subsequently underwent a renal transplantation with eventual loss of the allograft 5 years later due to recurrent HSP nephritis. Retransplantion was performed and the patient developed active HSP nephritis in her second allograft within a week after transplantation. In an effort to preserve her allograft, four cycles of PA were performed. Her proteinuria resolved and renal biopsies afterwards demonstrated marked reduction in mesangial IgA deposition. We conclude that PA may be useful in recurrent HSP nephritis, especially when used early. The risk of additional immunosuppression caused by PA needs to be considered. More studies need to be done to evaluate the efficacy of PA in this setting as well as to define the optimal treatment regimen.

A common polymorphism in the renin angiotensin system is associated with differential outcome of antihypertensive pharmacotherapy prescribed to Brazilian older women.

BACKGROUND: Since variations on the renin angiotensin (RA) system tend to exert effects on blood pressure, we investigated the association of the common ACE and AT1R polymorphisms with response to a multivariate pharmacotherapy. METHODS: This prospective study involved 169 hypertensive, community-dwelling older women. Genotypes were obtained by length analysis or direct sequencing of PCR products. Blood pressure-lowering pharmacotherapy was conducted according to current Brazilian Guidelines on Hypertension. RESULTS: Genotype frequencies were in agreement to the Hardy-Weinberg equilibrium. Interventions were found to represent actual hypertension-management practices in Brazil, and accounted for a significant reduction in both systolic (P<0.001) and diastolic (P<0.001) blood pressure. Concerning the effect of polymorphisms, no influence of the ACE and AT1R genotypes were found on the magnitude of the treatment-induced blood pressure reduction (P>0.05). Nonetheless, the clinical result varied according to the ACE alleles since mean systolic pressure was roughly 10 mm Hg higher in insertion (I) homozygotes than in the deletion (D) counterparts either in baseline (P=0.001) and endpoint (P=0.010). CONCLUSION: The outcome of the antihypertensive pharmacotherapy advocated by national guidelines was significantly influenced by the ACE I/D polymorphism but not by the AT1R 1166 A/C polymorphism among postmenopausal women.

RNA sequencing confirms similarities between PPI-responsive oesophageal eosinophilia and eosinophilic oesophagitis.

BACKGROUND: Although current American guidelines distinguish proton pump inhibitor-responsive oesophageal eosinophilia (PPI-REE) from eosinophilic oesophagitis (EoE), these entities are broadly similar. While two microarray studies showed that they have similar transcriptomes, more extensive RNA sequencing studies have not been done previously. AIM: To determine whether RNA sequencing identifies genetic markers distinguishing PPI-REE from EoE. METHODS: We retrospectively examined 13 PPI-REE and 14 EoE biopsies, matched for tissue eosinophil content, and 14 normal controls. Patients and controls were not PPI-treated at the time of biopsy. We did RNA sequencing on formalin-fixed, paraffin-embedded tissue, with differential expression confirmation by quantitative polymerase chain reaction (PCR). We validated the use of formalin-fixed, paraffin-embedded vs RNAlater-preserved tissue, and compared our formalin-fixed, paraffin-embedded EoE results to a prior EoE study. RESULTS: By RNA sequencing, no genes were differentially expressed between the EoE and PPI-REE groups at the false discovery rate (FDR) ≤0.01 level. Compared to normal controls, 1996 genes were differentially expressed in the PPI-REE group and 1306 genes in the EoE group. By less stringent criteria, only MAPK8IP2 was differentially expressed between PPI-REE and EoE (FDR = 0.029, 2.2-fold less in EoE than in PPI-REE), with similar results by PCR. KCNJ2, which was differentially expressed in a prior study, was similar in the EoE and PPI-REE groups by both RNA sequencing and real-time PCR. CONCLUSION: Eosinophilic oesophagitis and PPI-REE have comparable transcriptomes, confirming that they are part of the same disease continuum.

Interplay between circulating nitric oxide and interleukin-17 in elderly outpatients with non-inflammatory conditions.

Nitric oxide (NOx) availability in biological systems is associated with either favorable or unfavorable outcomes. In this sense, several studies bring about evidence that unbalanced NOx production may be underlying to the pathophysiology of vascular disorders. Our study investigated the possible association of clinical, biochemical and inflammatory variables with total circulating levels of NOx in elderly patients devoid of major inflammatory conditions. Clinical (demographics, lifestyle, anthropometry, pressoric traits) and biochemical characteristics (lipemic, glycemic and hormonal profiles) were assessed from 168 geriatrics outpatients eligible for primary care for age-related disorders. Furthermore, circulating levels of 10 inflammatory mediators and of NOx were measured. Correlation tests analyzed categorical or continuous traits according to serum NOx and found no association between NOx and any of the clinical or laboratory data but a negative correlation between plasma NOx concentrations and levels of the immune mediator IL17a (r = -0.236; P = 0.004). Evidence for a correlation between circulating NOx and IL17 is already present in the literature, mostly from studies conducted under inflammatory conditions. Our hypothesis is that such negative correlation can be attributed to an endogenous homeostatic system that IL17 production by the constitutively produced NOx from the vascular endothelium.

Serum levels of interleukin-2 differ between prostate cancer and benign prostatic hyperplasia / Níveis séricos de interleucina-2 diferem entre câncer de próstata e hiperplasia benigna da próstata

ABSTRACT Objective Investigation onthe systemic inflammatory profile ofpatients affected by prostate cancer (PCa) or prostatic hyperplasia (BPH) may contribute to characterize the pathological profile as well as enable identification of markers and promote alternatives for appropriate, less invasive treatments. Methods This research compared serum levels of 10 classic inflammatory mediators among patients aged 50 years or older affected by PCa or BPH. For this, clinical, biochemical, metabolic, anthropometric and inflammatory aspects of each patient was considered. Results From the statistical analysis, a weakpositive correlation (r = 0.16) between IL-2 with serum total PSA values was found. In addition, median serum IL-2 values were three times higher in patients with PCa compared to BPH patients. Conclusion By interpretation of current literature, we hypothesize that the activity of infiltratedtype M1 macrophages and activated cytotoxic cells in the neoplasm milieu might explain this increase of IL-2 as part of anendogenous anti-neoplastic response.

RESUMO Objetivo A investigação do perfil inflamatório sistêmico de pacientes acometidos por câncer de próstata (CaP) ou hiperplasia prostática (HPB) pode contribuir para caracterizar o perfil patológico, bem como possibilitar a identificação de marcadores e promover alternativas de tratamentos adequados e menos invasivos. Métodos Esta pesquisa comparou os níveis séricos de 10 mediadores inflamatórios clássicos em pacientes com 50 anos ou mais afetados por CaP ou HPB. Para tanto, foram considerados os aspectos clínicos, bioquímicos, metabólicos, antropométricos e inflamatórios de cada paciente. Resultados A partir da análise estatística, foi encontrada umacorrelação positiva fraca (r = 0,16) entre IL-2 com os valores de PSA total sé o. Além disso, os valores medianos de IL-2 no soro foram três vezes maiores em pacientes com CaP em comparação com pacientes com HPB. Conclusão Pela interpretação da literatura atual, hipotetizamos que a atividade de macrófagos do tipo M1 infiltrados e células citotóxicas ativadas no meio da neoplasia pode explicar esse aumento de IL-2 como parte de uma resposta antineoplásica endógena.

CHST6 mutations in North American subjects with macular corneal dystrophy: a comprehensive molecular genetic review.

PURPOSE: To evaluate mutations in the carbohydrate sulfotransferase-6 (CHST6) gene in American subjects with macular corneal dystrophy (MCD). METHODS: We analyzed CHST6 in 57 patients from 31 families with MCD from the United States, 57 carriers (parents or children), and 27 unaffected blood relatives of affected subjects. We compared the observed nucleotide sequences with those found by numerous investigators in other populations with MCD and in controls. RESULTS: In 24 families, the corneal disorder could be explained by mutations in the coding region of CHST6 or in the region upstream of this gene in both the maternal and paternal chromosome. In most instances of MCD a homozygous or heterozygous missense mutation in exon 3 of CHST6 was found. Six cases resulted from a deletion upstream of CHST6. CONCLUSIONS: Nucleotide changes within the coding region of CHST6 are predicted to alter the encoded protein significantly within evolutionary conserved parts of the encoded sulfotransferase. Our findings support the hypothesis that CHST6 mutations are cardinal to the pathogenesis of MCD. Moreover, the observation that some cases of MCD cannot be explained by mutations in CHST6 suggests that MCD may result from other subtle changes in CHST6 or from genetic heterogeneity.

Macular corneal dystrophy types I and II are caused by distinct mutations in the CHST6 gene in Iceland.

PURPOSE: To identify CHST6 mutations in five additional Icelandic cases of macular corneal dystrophy (MCD) type I and in four families with MCD type II from Iceland. METHODS: Genomic DNA was extracted from blood leukocytes of patients with MCD, their healthy family members, and from control individuals. CHST6 mutations were determined by PCR-sequencing. Immunophenotypes of MCD were determined by measuring antigenic keratan sulfate (AgKS) levels in serum and by an immunohistochemical study on corneal tissue. RESULTS: Five additional cases of MCD type I and four families with MCD type II from Iceland were studied. A homozygous p.A128V mutation in the coding region of the CHST6 gene was identified in four of the five MCD type I cases. The other person with MCD type I was a compound heterozygote for p.A128V and a frameshift p.V6fs resulting from a 10-base pair insertion (c.15_16insATGCTGTGCG). Four of five individuals with MCD type II were compound heterozygotes for p.A128V and p.V329L, thus sharing the same p.A128V mutation as MCD type I. One patient with MCD type II was homozygous for p.V329L. The p.V329L mutation was only found in MCD type II patients. An analysis of the upstream region of CHST6 disclosed no upstream deletion or replacements in Icelandic patients with MCD type II. CONCLUSIONS: The findings fit the haplotype analysis that we reported previously in Icelandic MCD families and indicate that different mutations in CHST6 cause MCD type I and type II in Iceland.