Genetics of Dupuytren's disease

Effects of mitochondrial transplantation on chronic pressure wound healing in a human patient

BACKGROUND AIMS

Wound healing is a multistage process that requires a concerted effort of various cell types. The intricate processes involved in the healing of wounds result in high energy requirements. Furthermore, mitochondria play a crucial role in the healing process because of their involvement in neo angiogenesis, growth factor synthesis, and cell differentiation. It is unclear how mitochondria transplantation, a promising new approach, influences wound healing.

METHODS

In this study, healthy autologous mitochondria obtained from skeletal muscle were injected into chronic pressure wounds as an intervention to promote wound healing.

RESULTS

Mitochondrial transplantation accelerated wound healing by reducing wound size, increasing granulation tissue, and hastening epithelialization.

CONCLUSIONS

This study is the first to demonstrate the therapeutic efficacy of mitochondrial transplantation in wound healing.

RNA-seq unravels distinct expression profiles of keloids and Dupuytren's disease

Keloid scars and Dupuytren's disease are two common, chronic, and incurable fibroproliferative disorders that, among other shared clinical features, may induce joint contractures. We employed bulk RNA sequencing to discern potential shared gene expression patterns and underlying pathological pathways between these two conditions. Our aim was to uncover potential molecular targets that could pave the way for novel therapeutic strategies. Differentially expressed genes (DEGs) were functionally annotated using Gene Ontology (GO) terms and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways with the Database for Annotation, Visualization, and Integrated Discovery (DAVID). The protein-protein-interaction (PPI) networks were constructed by using the Search Tool for the Retrieval of Interacting Genes (STRING) and Cytoscape. The Molecular Complex Detection (MCODE) plugin was used for downstream analysis of the PPI networks. A total of 1922 DEGs were identified within Dupuytren's and keloid samples, yet no overlapping gene expression profiles were detected. Significantly enriched GO terms were related to skin development and tendon formation in keloid scars and Dupuytren's disease, respectively. The PPI network analysis revealed 10 genes and the module analysis provided six protein networks, which might play an integral part in disease development. These genes, including CDH1, ERBB2, CASP3 and RPS27A, may serve as new targets for future research to develop biomarkers and/or therapeutic agents.

Integrating External Controls by Regression Calibration for Genome-Wide Association Study

Genome-wide association studies (GWAS) have successfully revealed many disease-associated genetic variants. For a case-control study, the adequate power of an association test can be achieved with a large sample size, although genotyping large samples is expensive. A cost-effective strategy to boost power is to integrate external control samples with publicly available genotyped data. However, the naive integration of external controls may inflate the type I error rates if ignoring the systematic differences (batch effect) between studies, such as the differences in sequencing platforms, genotype-calling procedures, population stratification, and so forth. To account for the batch effect, we propose an approach by integrating External Controls into the Association Test by Regression Calibration (iECAT-RC) in case-control association studies. Extensive simulation studies show that iECAT-RC not only can control type I error rates but also can boost statistical power in all models. We also apply iECAT-RC to the UK Biobank data for M72 Fibroblastic disorders by considering genotype calling as the batch effect. Four SNPs associated with fibroblastic disorders have been detected by iECAT-RC and the other two comparison methods, iECAT-Score and Internal. However, our method has a higher probability of identifying these significant SNPs in the scenario of an unbalanced case-control association study.

Exploring the potential relationship between frozen shoulder and Dupuytren's disease through bioinformatics analysis and machine learning

Background

Frozen shoulder (FS) and Dupuytren's disease (DD) are two closely related diseases, but the mechanism of their interaction is unknown. Our study sought to elucidate the molecular mechanism of these two diseases through shared gene and protein interactions.

Methods

GSE75152 and GSE140731 data were downloaded from the Gene Expression Omnibus (GEO) database, and shared genes between FS and DD were selected by using R packages. Then, we used Cytoscape software and the STRING database to produce a protein-protein interaction (PPI) network. Important interaction networks and hub genes were selected through MCODE and cytoHubba algorithms. To explore the potential mechanisms of the development of the two diseases, the hub genes were further enriched by GO and KEGG analyses. We predicted the transcription factors (TFs) of hub genes with Transcriptional Regulatory Relationships Unraveled by Sentence-based Text mining (TRRUST). Moreover, we identified candidate genes for FS with DD with cytoHubba and machine learning algorithms. Finally, we analyzed the role of immunocyte infiltration in FS and constructed the relationship between candidate genes and immunocytes in FS.

Results

We identified a total of 321 shared genes. The results of GO and KEGG enrichment of shared genes showed that extracellular matrix and collagen fibril tissue play a certain role in the occurrence and development of disease. According to the importance of genes, we constructed the key PPI network of shared genes and the top 15 hub genes for FS with DD. Then, we predicted that five TFs are related to the hub genes and are highly expressed in the FS group. Machine learning results show that the candidate genes POSTN and COL11A1 may be key for FS with DD. Finally, immune cell infiltration revealed the disorder of immunocytes in FS patients, and expression of candidate genes can affect immunocyte infiltration.

Conclusion

We identified a PPI network, 15 hub genes, and two immune-related candidate genes (POSTN and COL11A1) using bioinformatics analysis and machine learning algorithms. These genes have the potential to serve as diagnostic genes for FS in DD patients. Furthermore, our study reveals disorder of immunocytes in FS.

Analysis of a National Database Investigating Development of Trigger Finger after Treatment of Dupuytren Disease

Dupuytren disease is associated with inflammation and myofibroblast overgrowth, as is stenosing tenosynovitis (trigger finger). Both are linked with fibroblast proliferation, but a potential associative link between the diseases is unknown. The purpose of this study was to evaluate the progression of trigger finger following treatment for Dupuytren contracture in a large database.

Methods

A commercial database encompassing 53 million patients was utilized from January 1, 2010 to March 31, 2020. The study cohort included patients diagnosed with either Dupuytren disease or trigger finger utilizing International Classification Codes 9 and 10. Terminology codes were used to identify common Dupuytren procedures, as well as trigger finger release. Logistic regression analysis was used to define independent risk factors for developing trigger finger.

Results

A total of 593,606 patients were diagnosed with trigger finger. Of these patients, 15,416 (2.6%) were diagnosed with trigger finger after diagnosis of Dupuytren disease, whereas 2603 (0.4%) patients were diagnosed with trigger finger after treatment of Dupuytren contracture. Independent risk factors for trigger finger included age 65 years or older (OR 1.00, P < 0.05), diabetes (OR 1.12, P < 0.05) and obesity (OR 1.20, P < 0.005). Patients who received collagenase clostridium histolyticum treatment (OR 0.34, P < 0.005) for Dupuytren contracture were significantly less likely to develop trigger finger.

Conclusions

Dupuytren contracture is associated with inflammation and subsequent trigger finger development at a higher rate than the background population frequency. Collagenase clostridium histolyticum injection may lead to a decreased risk of trigger finger requiring surgical intervention in patients with risk factors.

Fibrosis-Associated Signaling Molecules Are Differentially Expressed in Palmar Connective Tissues of Patients with Carpal Tunnel Syndrome and Dupuytren's Disease

Carpal tunnel syndrome (CTS) and Dupuytren's disease (DD) are fibrotic conditions that affect the connective tissue of the hand and limit its functionality. The exact molecular mechanism underlying the fibrosis is unknown, and only some profibrotic factors have been investigated. In this cross-sectional study, we analyzed the expression of FGF signaling pathway molecules associated with fibrotic changes in the palmar fascia and the flexor retinaculum of 15 CTS patients and both clinically affected and unaffected palmar fascia of 15 DD patients, using immunofluorescence techniques. The expression of FGFR1, FGFR2, and CTGF in the blood vessel walls and surrounding connective tissue cells differed significantly between the analyzed groups, with changes in expression present even in clinically unremarkable tissues from DD patients. We also found altered expression of the analyzed factors, as well as TGF-β1 and syndecan-1 in DD-associated sweat glands, possibly implicating their role in the pathophysiology of the disease. The increased expression of profibrotic factors in the clinically unaffected palmar fascia of DD patients may indicate that more extensive excision is needed during surgical treatment, while the profibrotic factors could be potential targets for developing pharmacological therapeutic strategies against DD-associated fibrosis.

Palmar skin elasticity measured by the Cutometer MPA 580 is decreased in mild Dupuytren's disease compared to healthy controls

Introduction

Involvement of the palmar skin is often seen in patients with Dupuytren's disease (DD) with severe finger contractures. However, skin elasticity may be already decreased earlier in the disease. The Cutometer MPA 580 could provide an objective skin measurement tool to assess this decrease in elasticity. Linking objective skin measurements to functional outcome measures could lead to better prediction of disease progression. We set up a study to investigate if the Cutometer was able to detect differences in skin elasticity between patients with mild Dupuytren's disease and healthy controls.

Methods

A cross-sectional analytical study was performed. Three assessors measured skin elasticity (palmar hand) on two sites using the Cutometer on 30 patients with mild DD and 30 healthy controls. Student's t-test was used to evaluate differences in skin elasticity and a linear model to evaluate interactions between the groups and sites.

Results

Significant differences in skin elasticity were found between DD patients and controls, as well as differences based on the location examined.

Discussion

Similar to other skin conditions, the Cutometer MPA 580 was able to demonstrate a significant lower elasticity in the palmar skin in DD patients compared to healthy controls. A decrease in skin elasticity in different locations of the hand correlated with areas that often pose problems in the treatment of more severe DD. The Cutometer could potentially be a tool to identify these areas earlier in the disease.

Epineural Methylene Blue Injection May Aid Localization of Digital Nerves in Dupuytren's Surgery

Background

In Dupuytren's surgery, limited fasciectomy is still the gold-standard treatment. A relatively high risk of iatrogenic nerve injury has been observed especially when the spiral cords of the Dupuytren's tissue pull digital nerves away from their normal anatomical location. Intraoperative neural marking could facilitate locating the potentially displaced nerves. Hence, surgery could be undertaken more quickly with a lower risk of iatrogenic nerve injury.

Objectives

We hypothesize that digital nerves may be stained with methylene blue (MB) in vivo providing a visual aid to distinguish them from Dupuytren's tissue. We aim to (a) test an in vivo nerve staining technique using MB in a rat sciatic nerve model and to (b) assess the safety of epineural MB injection.

Methods

Three experiments were performed: first, the effects of (a) sham surgery, (b) epineural needle insertion, and (c) 40 μL epineural saline injection were tested in the rat sciatic nerve. Second, we determined the (a) histoanatomical localization of the epineurally injected 40 µL 1 m/m% MB stock solution and (b) we tested which saline dilution (i.e., 1:40, 1:80, and 1:160) of the stock solution does provide optimal blue color upon 40 µL epineural injection. Third, the functional and morphological effect of 40 µL 1:80 diluted MB injection was compared with that of saline, injected into the contralateral sciatic nerve. The functional effects were tested by assessing the pain threshold by using a dynamic plantar esthesiometer (DPA) and by examination of the animal's gate and paw posture. Sciatic nerves were subjected to histological examination and morphometry to test structural damage.

Results

Neither epineural needle insertion nor saline injection caused any functional or morphological changes. Histological examination revealed that the MB stained the epineural compartment. Epineural injection of 40 μL 1:80 diluted MB into the sciatic nerve stained an 18.18-mm segment of the nerve distal to the puncture point. DPA revealed unchanged pain threshold values on the plantar surface of the limbs. Normal gait and foot posture suggested normal motor functions in all groups. No histological changes were seen in the stained nerves, and the nerve fiber density remained unchanged.

Conclusion

We demonstrated that in vivo nerve staining with MB is a suitable method to mark nerves without causing detectable negative effect to the stained nerve. Human trials are required to prove the efficacy of the technique in Dupuytren's disease.

Palmar and plantar fibromatosis: a review

Palmar fibromatosis (Dupuytren disease/contracture) is the most common type of fibromatosis, defined as a benign proliferation of fibroblasts and myofibroblasts. The disease process is most common in white, middle-aged and older men occurring at the distal palmar crease leading to nodules and contracture, which in many cases recur after surgical treatment. In a similar process, plantar fibromatosis (Ledderhose disease) is a proliferation of fibroblasts and myofibroblasts on the plantar aponeurosis of mostly middle-aged patients that may lead to painful nodules but usually does not lead to contracture. Both processes are histologically similar, composed of a bland cellular proliferation of spindle cells with a bluish appearance and with a variable amount of background collagen, depending on the age of the lesion. The etiology of both lesions is still uncertain, while treatment ranges from observation to surgery, with some pharmacologic agents being investigated with mixed success. In this paper we provide an overview of both processes with regards to clinical and radiologic findings, pathophysiology, diagnosis, treatment, and prognosis.

Biomimetic analyses of interactions between macrophages and palmar fascia myofibroblasts derived from Dupuytren's disease reveal distinct inflammatory cytokine responses

Dupuytren's disease (DD) is a common and heritable fibrosis of the hand. It is characterized by the shortening and thickening of the palmar fascia into myofibroblastic nodules that can progress to palmar-digital contractures and permanent loss of dexterity. Molecular analyses of DD tissues and the presence of inflammatory cell infiltrates suggest a pathogenesis initiated by a proinflammatory fascial milieu that promotes myofibroblast activation and palmar fascia contractures. However, the relative contributions of vascular and/or tissue derived immune system cells and cytokine-sensitive stromal myofibroblasts to the development of this proinflammatory microenvironment are poorly understood. To gain insights into this process, we have developed and tested a collagen-based 3D tissue biomimetic co-culture system to assess paracrine interactions between THP-1-derived pro-inflammatory macrophages and primary human palmar fascia myofibroblasts (PFMs). We observed significant and reproducible impacts of collagen-adherent macrophage and PFM co-cultures on the cytokine gene expression profiles of these cells compared to their respective monocultures, and significant changes to the resulting cytokine milieu in their shared culture media, notably TNF and IL-6. Our findings are consistent with central roles for PFMs in cytokine production and immunoregulation of the pro-inflammatory milieu hypothesized to promote DD development.

The worldwide prevalence of the Dupuytren disease: a comprehensive systematic review and meta-analysis

Background

The Dupuytren disease is a benign fibroproliferative disorder that leads to the formation of the collagen knots and fibres in the palmar fascia. The previous studies reveal different levels of Dupuytren’s prevalence worldwide; hence, this study uses meta-analysis to approximate the prevalence of Dupuytren globally.

Methods

In this study, systematic review and meta-analysis have been conducted on the previous studies focused on the prevalence of the Dupuytren disease. The search keywords were Prevalence, Prevalent, Epidemiology, Dupuytren Contracture, Dupuytren and Incidence. Subsequently, SID, MagIran, ScienceDirect, Embase, Scopus, PubMed and Web of Science databases and Google Scholar search engine were searched without a lower time limit and until June 2020. In order to analyse reliable studies, the stochastic effects model was used and the I² index was applied to test the heterogeneity of the selected studies. Data analysis was performed within the Comprehensive Meta-Analysis Software version 2.0.

Results

By evaluating 85 studies (10 in Asia, 56 in Europe, 2 in Africa and 17 studies in America) with a total sample size of 6628506 individuals, the prevalence of Dupuytren disease in the world is found as 8.2% (95% CI 5.7–11.7%). The highest prevalence rate is reported in Africa with 17.2% (95% CI 13–22.3%). According to the subgroup analysis, in terms of underlying diseases, the highest prevalence was obtained in patients with type 1 diabetes with 34.1% (95% CI 25–44.6%). The results of meta-regression revealed a decreasing trend in the prevalence of Dupuytren disease by increasing the sample size and the research year (P < 0.05).

Conclusion

The results of this study show that the prevalence of Dupuytren disease is particularly higher in alcoholic patients with diabetes. Therefore, the officials of the World Health Organization should design measures for the prevention and treatment of this disease.

Mitochondria in skin health, aging, and disease

The skin is a high turnover organ, and its constant renewal depends on the rapid proliferation of its progenitor cells. The energy requirement for these metabolically active cells is met by mitochondrial respiration, an ATP generating process driven by a series of protein complexes collectively known as the electron transport chain (ETC) that is located on the inner membrane of the mitochondria. However, reactive oxygen species (ROS) like superoxide, singlet oxygen, peroxides are inevitably produced during respiration and disrupt macromolecular and cellular structures if not quenched by the antioxidant system. The oxidative damage caused by mitochondrial ROS production has been established as the molecular basis of multiple pathophysiological conditions, including aging and cancer. Not surprisingly, the mitochondria are the primary organelle affected during chronological and UV-induced skin aging, the phenotypic manifestations of which are the direct consequence of mitochondrial dysfunction. Also, deletions and other aberrations in the mitochondrial DNA (mtDNA) are frequent in photo-aged skin and skin cancer lesions. Recent studies have revealed a more innate role of the mitochondria in maintaining skin homeostasis and pigmentation, which are affected when the essential mitochondrial functions are impaired. Some common and rare skin disorders have a mitochondrial involvement and include dermal manifestations of primary mitochondrial diseases as well as congenital skin diseases caused by damaged mitochondria. With studies increasingly supporting the close association between mitochondria and skin health, its therapeutic targeting in the skin-either via an ATP production boost or free radical scavenging-has gained attention from clinicians and aestheticians alike. Numerous bioactive compounds have been identified that improve mitochondrial functions and have proved effective against aged and diseased skin. In this review, we discuss the essential role of mitochondria in regulating normal and abnormal skin physiology and the possibility of targeting this organelle in various skin disorders.

Dupuytren's disease: A reality in Black Africa

Long regarded as a disease exclusively found amongst Northern Europeans, Dupuytren's disease was seldom studied amongst Black Africans. Thus, we sought to study the impact of Dupuytren's disease, its etiological, clinical and evolutionary peculiarities on a segment of the Senegalese population. This study analyzed data derived from clinical observations carried out between January 2006 and December 2018. It involved Senegalese subjects with Dupuytren's disease, the patients' history, profession, habitus, clinical findings, therapeutic modalities and disease staging. The population included 20 men and 6 women averaging 63.5 years of age (range 45-77). None of the patients reported a family of Dupuytren's disease. Twelve patients had diabetes, 11 were smokers and 22 were engaged exclusively in manual labor. The condition was bilateral in 14 cases. Tubiana stages N, I, II, III and IV were found in 31, 15, 9, 5 and 6 rays, respectively. Conservative treatment was done in 11 patients. Surgical treatment was carried out in the other 15 patients: needle fasciotomy (N=10) including two bilateral involvement and open fasciectomy (N=7). Functional outcomes were satisfactory. Lesions were all stable in the short and medium term. Two patients had progressive lesions on a longer-term basis. Dupuytren's disease is real among Afro-descendants from Senegal even though it is seldom studied. Based on the patients' recollection of Dupuytren's disease in their families, heredity is not yet a proven factor. The early forms are more common, and the lesions remain stable for a long time.

Increased Risk of Incident Disease in Men with Peyronie's Disease: Analysis of U.S. Claims Data

BACKGROUND

The subsequent health risks associated with Peyronie's disease (PD) are unknown.

AIM

This cohort study assesses the risk of developing auto-immune conditions and common chronic health conditions after a diagnosis of PD. We hypothesize that an increase in auto-immune disease will be evident in men with PD, as has been suggested in smaller studies.

METHODS

We determined the longitudinal incidence of 13 auto-immune diseases and 25 common chronic conditions in a cohort from the Truven Health Analytics (Ann Arbor, Michigan, USA) database from 2007-2013. The cohort included men with 1 of 3 exposures in 2007: (1) men with PD, (2) men with erectile dysfunction (ED) but not PD, and (3) men without PD or ED, matched on age and follow-up duration.

OUTCOMES

To assess incidence, we utilized a Cox regression model adjusting for age, smoking, obesity, health care visits per year, urology visits per year, and years of follow-up.

RESULTS

We included 8,728 men with PD; 204,147 men with ED; and 87,280 controls. Men with PD had an increased risk of developing benign prostatic hyperplasia (hazard ratio [HR] 1.21, 95% CI 1.16-1.27), prostatitis (HR 1.21, 95% CI 1.12-1.31), and lower urinary tract symptoms (HR 1.10, 95% CI 1.05-1.16) when compared to both men with ED and age-matched controls without ED or PD even when controlling for the number of urology visits per year. Compared to controls, men with PD also had an increased risk of developing keloids. No significant risk for any auto-immune disease was observed.

CLINICAL IMPLICATIONS

Clinicians should have heightened awareness for these relevant co-morbidities when treating men with PD.

STRENGTHS & LIMITATIONS

Utilizing a claims database provides one of the largest cohorts of men with PD ever published but claims databases lack some individual patient data such as risk factors and demographic information relevant to PD, including: penile injury, history of urologic procedures, and other lifestyle factors.

CONCLUSION

Men with PD had a higher risk of benign prostatic hyperplasia, lower urinary tract symptoms, prostatitis, and keloids after a diagnosis of PD, but no increased risk of auto-immune conditions. These findings suggest a common etiology for these conditions that may manifest itself in diseases at different times in men's life cycle. Pastuszak AW, Rodriguez KM, Solomon ZJ, et al. Increased Risk of Incident Disease in Men with Peyronie's Disease: Analysis of U.S. Claims Data. J Sex Med 2018;15:894-901.

The Etiology of Peyronie's Disease: Pathogenesis and Genetic Contributions

INTRODUCTION

Peyronie's disease (PD) is a chronic fibrosing condition that contributes to penile deformity, curvature, and pain. Initial familial studies demonstrated potential genetic links to PD. Since that time, very few investigations have significantly advanced the science in this area. Hence, there is a large opportunity and significant need to better study the underlying genomics and pathogenesis of PD.

AIM

To summarize the current genomic literature relevant to PD.

METHODS

A review was performed of all PubMed-indexed literature from 1970-2018 relating to the pathophysiology and genetics of PD. Key findings were categorically summarized to include epidemiology, risk factors, inheritance patterns, chromosomal instability, genetic associations, epigenetics, differential gene expression, and preclinical models of PD.

MAIN OUTCOME MEASURES

Summary of the current literature on the genetics of PD.

RESULTS

PD is a common condition and has several known risk factors and comorbid disease associations. Although men with PD are believed to be genetically predisposed, there are likely several subtypes of the condition, each with varied pathophysiological disorders and contributing factors. Available data suggest that PD is associated with underlying genetic instability, including dysregulation of genes relating to fibrosis and cellular degradation, thus, resulting in abnormal plaque development and penile deformity. Preclinical models, including cell cultures and rat models, demonstrate several consistencies with PD clinical and histopathologic characteristics; however, an ideal model with spontaneous development of PD is lacking.

CONCLUSION

Based on limited data, PD likely represents a heterogeneous condition, with both heritable and environmentally-driven epigenetic factors contributing to its development and progression. However, there remains a significant gap in the literature on the underlying cause and pathophysiology of the condition, suggesting a substantial need for further investigation and study. Sharma KL, Alom M, Trost L. The Etiology of Peyronie's Disease: Pathogenesis and Genetic Contributions. Sex Med Rev 2020;8:314-323.

Association between occupational exposure and Dupuytren's contracture using a job-exposure matrix and self-reported exposure in the CONSTANCES cohort

BACKGROUND

Although several studies highlighted an association between occupational exposure and Dupuytren's contracture (DC), they were often limited by the highly selected population. We aimed to study this association using a job-exposure matrix (JEM) and self-reported exposure in a large cohort.

METHODS

From CONSTANCES, a French population-based prospective cohort, we retrieved sex, age, social position, alcohol/tobacco intake and diabetes. Lifetime exposures were assessed by two different methods: with the biomechanical JEM 'JEM Constances', we assessed exposure to vibration and/or forearm rotation for participants whose work history was available, and from a self-administered questionnaire, we retrieved self-reported exposure to arduous work and/or carrying heavy loads. Surgery for DC was collected from the French Health Administrative database from 2009 to 2016. Multivariate logistic regression models adjusted for confounders were built to assess association between surgery for DC and occupational exposures.

RESULTS

Work history was retrieved for 23 795 subjects among whom 98 underwent surgery for DC. Adjusted OR (aOR) was 2.08 (1.03-4.2) for being ever exposed to vibration and/or forearm rotation for subjects <60 years and 1.20 (0.69-2.08) for subjects ≥60 years. Data for self-reported exposure were available for 81 801 participants among whom 367 underwent surgery for DC. aOR for being exposed more than 20 years to arduous work and/or carrying heavy loads was 2.01 (1.32-3.04) for subjects <60 years and 1.04 (0.7-1.54) for subjects ≥60.

CONCLUSIONS

Manual work is associated with surgery for DC among younger subjects. Monitoring exposed workers is important to prevent future functional limitations.

Dupuytren contracture as a sign of systemic disease

Dupuytren contracture (DC) is predominantly an autosomal dominant disorder characterized by hypertrophy and contraction of the palmar fascia that results in tethered flexion of the affected digits. It has its highest prevalence in the North European population or in people of Viking descent, and its incidence is growing with age. DC shares a common inheritance mode, predisposing factors, comorbidities, pathophysiology, and evolution with Ledderhose disease, Garrod knuckle pads, and Peyronie disease. Nonmelanoma skin cancer also has a higher incidence in the population of North European phenotype and apparently a common genetic polymorphism. Psoriasis shares many risk factors and comorbidities with DC and has a higher prevalence in patients with DC. We suggest a close relationship among DC, some skin malignancies, and psoriasis. Regular monitoring for those skin diseases in all patients with DC is highly recommended.

Dupuytren's and Ledderhose Diseases in a Family with LMNA-Related Cardiomyopathy and a Novel Variant in the ASTE1 Gene

Dupuytren's disease (palmar fibromatosis) involves nodules in fascia of the hand that leads to flexion contractures. Ledderhose disease (plantar fibromatosis) is similar with nodules of the foot. While clinical aspects are well-described, genetic mechanisms are unknown. We report a family with cardiac disease due to a heterozygous LMNA mutation (c.736C>T, p.Gln246Stop) with palmar/plantar fibromatosis and investigate the hypothesis that a second rare DNA variant increases the risk for fibrotic disease in LMNA mutation carriers. The proband and six family members were evaluated for the cardiac and hand/feet phenotypes and tested for the LMNA mutation. Fibroblast RNA studies revealed monoallelic expression of the normal LMNA allele and reduced lamin A/C mRNAs consistent with LMNA haploinsufficiency. A novel, heterozygous missense variant (c.230T>C, p.Val77Ala) in the Asteroid Homolog 1 (ASTE1) gene was identified as a potential risk factor in fibrotic disease using exome sequencing and family studies of five family members: four LMNA mutation carriers with fibromatosis and one individual without the LMNA mutation and no fibromatosis. With a possible role in epidermal growth factor receptor signaling, ASTE1 may contribute to the increased risk for palmar/plantar fibromatosis in patients with Lamin A/C haploinsufficiency.

Evidence-Based Medicine: Options for Dupuytren's Contracture: Incise, Excise, and Dissolve

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Understand updates in the basic science, epidemiology, and treatment of Dupuytren's disease. 2. Understand treatment with needle aponeurotomy, collagenase, and fasciectomy. 3. Understand advanced needle techniques for Dupuytren's contracture. 4. Understand the safety and effectiveness of a new treatment, collagenase.

SUMMARY

The literature on Dupuytren's disease encompasses many specialties. Its treatment is generally by perforating, excising, or dissolving the affected tissues. This article reviews the changing understanding of this disease and treatment options.

Multiple Recurrences in Aggressive Forms of Dupuytren's Disease-Can Patients Benefit from Repeated Selective Fasciectomy?

Background:

In Dupuytren’s disease (DD), limited fasciectomy is the mainstay of surgical therapy in patients at risk of contractures and disease recurrences. New minimally invasive treatments such as injection of collagenase clostridium histolyticum have evolved as a common tool for the preliminary treatment of Dupuytren’s contractures. However, recurrences and their therapy remain controversial. In this study, we evaluate the benefit of repeated limited fasciectomy in patients with aggressive forms of the disease and multiple recurrences of contractures.

Methods:

We evaluated the outcome of 16 patients undergoing limited fasciectomy 3 or more times on a single hand.

Results:

Postoperatively, 10 of 13 (76.9%) patients were satisfied with the clinical result after the last operation; 10 of 12 (83.3%) patients would choose to have their surgery repeated, if so needed. The mean improvement of proximal interphalangeal joint range of motion was 59.2 degrees (SD 26.8) and 86.2% (SD 19.9). There were no severe complications after treatment within the observed time period.

Conclusions:

Our findings demonstrate that patients with recurrence of contractures after multiple previous treatments in aggressive forms of DD can benefit from surgical intervention. In conclusion, repeated limited fasciectomy remains indicated in patients after previous surgeries with DD.

Anti-fibrotic action of pirfenidone in Dupuytren's disease-derived fibroblasts

BACKGROUND

Dupuytren's disease (DD) is a complex fibro-proliferative disorder of the hand that is often progressive and eventually can cause contractures of the affected fingers. Transforming growth factor beta (TGF-β1) has been implicated as a key stimulator of myofibroblast activity and fascial contraction in DD. Pirfenidone (PFD) is an active small molecule shown to inhibit TGF-β1-mediated action in other fibrotic disorders. This study investigates the efficacy of PFD in vitro in inhibiting TGF-β1-mediated cellular functions leading to Dupuytren's fibrosis.

METHODS

Fibroblasts harvested from (DD) and carpal tunnel (CT)- tissues were treated with or without TGF-β1 and/or PFD and were subjected to cell migration, cell proliferation and cell contraction assays. ELISA; western blots and real time RT-PCR assays were performed to determine the levels of fibronectin; p-Smad2/Smad3; alpha-smooth muscle actin (α-SMA), α2 chain of type I collagen and α1 chain of type III collagen respectively.

RESULTS

Our results show that PFD effectively inhibits TGF-β1-induced cell migration, proliferation and cell contractile properties of both CT- and DD-derived fibroblasts. TGF-β1-induced α-SMA mRNA and protein levels were inhibited at the higher concentration of PFD (800 μg/ml). Interestingly, TGF-β1 induction of type I and type III collagens and fibronectin was inhibited by PFD in both CT- and DD- derived fibroblasts, but the effect was more prominent in DD cells. PFD down-regulated TGF-β1-induced phosphorylation of Smad2/Smad3, a key factor in the TGF-β1 signaling pathway.

CONCLUSION

Taken together these results suggest the PFD can potentially prevent TGF-β1-induced fibroblast to myofibroblast transformation and inhibit ECM production mainly Type I- and Type III- collagen and fibronectin in DD-derived fibroblasts. Further in-vivo studies with PFD may lead to a novel therapeutic application in preventing the progression or recurrence of Dupuytren's disease.

The Genetic Basis of Peyronie Disease: A Review

INTRODUCTION

Peyronie disease (PD) is a progressive fibrotic disorder of the penile tunica albuginea that results in fibrotic penile plaques and can lead to penile deformity. Characterized by aberrant fibrosis resulting in part from the persistence of myofibroblasts and altered gene expression, the molecular factors underpinning PD and other related fibrotic diatheses are just being elucidated. A genetic link to PD was first identified three decades ago using pedigree analyses. However, the specific genetic factors that predispose patients to aberrant fibrosis remain unknown, and the relations between these fibrotic conditions and other heritable diseases, including malignancy, are uncharacterized.

AIM

To review the current landscape linking molecular and genetic factors to aberrant fibrosis in PD and related fibrotic diatheses, including Dupuytren disease.

METHODS

Review and evaluation of the literature from 1970 to the present for genetic factors associated with PD were performed.

MAIN OUTCOME MEASURES

Data describing the genetic factors associated with PD were obtained.

RESULTS

We describe the known structural chromosomal abnormalities and single-nucleotide polymorphisms associated with fibrotic diatheses and discuss the spectrum of differential gene expression data comparing normal tissues with those derived from men with PD or Dupuytren disease. We discuss epigenetic mechanisms that might regulate gene expression and alter predisposition to fibrosis.

CONCLUSION

Although the current understanding of the genetic factors associated with PD is limited, significant advances have been made during the past three decades. Further research is necessary to provide a more comprehensive understanding of the landscape of genetic factors responsible for the development of PD.

Dupuytren's disease therapy: targeting the vicious cycle of myofibroblasts?

INTRODUCTION

Dupuytren's disease (DD) is a proliferative fibromatosis of the hand, which causes permanent flexion contracture of the digits and, ultimately, loss of function. The treatment of DD is complex and involves surgical and nonsurgical approaches, with the goal of removing the affected tissue. New biological targets are under investigation in order to develop innovative therapies.

AREAS COVERED

The etiology of DD is still unknown. Several authors who focused their studies on the genetics of DD recognized an inherited autosomal dominant pattern. Actually, DD is a multifactorial and complex disease. Myofibroblasts are thought to play a crucial role in its pathogenesis, although their origin is not clear.

EXPERT OPINION

There is a general consensus that a better understanding of cellular and molecular mechanisms of DD will lead to the design of more specific and effective treatment alternatives. In this review, the authors hypothesize a new biological model for DD pathology, where myofibroblasts enhance the reservoir of the disease acting as if in a vicious cycle. This could help, ultimately, in identifying new therapeutic strategies to treat this common and disabling fibroproliferative disorder.

Epidemiological profile of Dupuytren's disease in Taiwan (Ethnic Chinese): a nationwide population-based study

BACKGROUND

The epidemiologic profile of ethnic Chinese patients with Dupuytren's disease is unknown. We therefore investigated the epidemiology of Dupuytren's disease using Taiwan's National Health Insurance Research Database.

METHODS

Patients who filed claims for treatment for Dupuytren's disease between January 2000 and December 2011 were identified in the database. Age- and gender-specific incidences were estimated by dividing the incidence number by population data.

RESULTS

We identified 1,078 patients with Dupuytren's disease (681 men, 397 women; male/female ratio: 1:1.72). The annual incidence rate ranged from 0.39-0.63/10(5) for men and 0.14-0.44/10(5) for women. A trend analysis revealed a rising trend in the annual incidence from 2001 to 2011 (p = 0.0199). The prevalence rate increased steadily from 0.46/10(5) in 2000 to 4.52/10(5) in 2011 (p = 0.0186). The mean age at onset was significantly higher in men than in women (60.7 ± 18.4 vs. 53.7 ± 15.5 years). Peak age at onset for men was 70-79 (28.1%) and for women was 50-59 (33.5%). Men > 60 years old had higher incidence rates than did women (incidence rate ratios: 2.0, 4.5, and 6.6 for those 60-69, 70-79, and ≥ 80, respectively). Hypertension (29.6%), diabetes mellitus (21.9%), hyperlipidemia (14.8%), ischemic heart disease (10.5%), and chronic obstructive pulmonary disease (8.0%) were the most common comorbidities.

CONCLUSIONS

The incidence and prevalence of Dupuytren's disease and the male/female ratio were significantly lower in ethnic Chinese than in Western ethnic groups. Moreover, the age at onset was significantly lower in ethnic Chinese women. However, the incidences of three comorbidities (hypertension, diabetes mellitus, and hyperlipidemia) were similar to those in other ethnicities.

SNPs previously associated with Dupuytren's disease replicated in a North American cohort

OBJECTIVE

Dupuytren's disease is a progressive fibrosis of the hand that often results in debilitating flexion contractures. Its etiology is not completely understood but likely involves both genetic and environmental factors. A recent study performed in Europe identified DNA variants that associate with Dupuytren's disease. Given the likelihood for genetic variation among populations, we planned to validate the genetic variants identified by this study in a North American population.

METHODS

In the Marshfield Clinic's Personalized Medicine Research Project, 296 cases with Dupuytren's disease were identified and matched 3-to-1 to controls without Dupuytren's disease. Clinical data were abstracted from the electronic medical record. The top 12 single nucleotide polymorphisms (SNPs) from the European study were selected and tested in a multiplex assay using the MassArray Analyzer 4 (Sequenom, Inc., San Diego, CA). Differences in allele frequency were determined, and variants with a P value of <0.004 were considered significant.

RESULTS

We replicated 5 of the 12 SNPs previously reported to be associated with Dupuytren's disease.

CONCLUSION

Our findings support a role for the Wnt signaling pathway in the development of Dupuytren's disease, and suggest that further study of this pathway may result in early diagnosis and non-surgical treatments for Dupuytren's disease.

Identification of histological patterns in clinically affected and unaffected palm regions in dupuytren's disease

Dupuytren's disease is a fibro-proliferative disease characterized by a disorder of the extracellular matrix (ECM) and high myofibroblast proliferation. However, studies failed to determine if the whole palm fascia is affected by the disease. The objective of this study was to analyze several components of the extracellular matrix of three types of tissues—Dupuytren's diseased contracture cords (DDC), palmar fascia clinically unaffected by Dupuytren's disease contracture (NPF), and normal forehand fascia (NFF). Histological analysis, quantification of cells recultured from each type of tissue, mRNA microarrays and immunohistochemistry for smooth muscle actin (SMA), fibrillar ECM components and non-fibrillar ECM components were carried out. The results showed that DDC samples had abundant fibrosis with reticular fibers and few elastic fibers, high cell proliferation and myofibroblasts, laminin and glycoproteins, whereas NFF did not show any of these findings. Interestingly, NPF tissues had more cells showing myofibroblasts differentiation and more collagen and reticular fibers, laminin and glycoproteins than NFF, although at lower level than DDC, with similar elastic fibers than DDC. Immunohistochemical expression of decorin was high in DDC, whereas versican was highly expressed NFF, with no differences for aggrecan. Cluster analysis revealed that the global expression profile of NPF was very similar to DDC, and reculturing methods showed that cells corresponding to DDC tissues proliferated more actively than NPF, and NPF more actively than NFF. All these results suggest that NPF tissues may be affected, and that a modification of the therapeutic approach used for the treatment of Dupuytren's disease should be considered.

Mitochondrial dysfunction: a neglected component of skin diseases

Aberrant mitochondrial structure and function influence tissue homeostasis and thereby contribute to multiple human disorders and ageing. Ten per cent of patients with primary mitochondrial disorders present skin manifestations that can be categorized into hair abnormalities, rashes, pigmentation abnormalities and acrocyanosis. Less attention has been paid to the fact that several disorders of the skin are linked to alterations of mitochondrial energy metabolism. This review article summarizes the contribution of mitochondrial pathology to both common and rare skin diseases. We explore the intriguing observation that a wide array of skin disorders presents with primary or secondary mitochondrial pathology and that a variety of molecular defects can cause dysfunctional mitochondria. Among them are mutations in mitochondrial- and nuclear DNA-encoded subunits and assembly factors of oxidative phosphorylation (OXPHOS) complexes; mutations in intermediate filament proteins involved in linking, moving and shaping of mitochondria; and disorders of mitochondrial DNA metabolism, fatty acid metabolism and heme synthesis. Thus, we assume that mitochondrial involvement is the rule rather than the exception in skin diseases. We conclude the article by discussing how improving mitochondrial function can be beneficial for aged skin and can be used as an adjunct therapy for certain skin disorders. Consideration of mitochondrial energy metabolism in the skin creates a new perspective for both dermatologists and experts in metabolic disease.

Psychometric properties of health-related quality of life instruments in patients undergoing palmar fasciectomy for dupuytren's disease: a prospective study

BACKGROUND

The traditional outcome measured following treatment of Dupuytren's Disease (DD) has been digital range of motion; specifically the gain in digital extension. The outcomes research movement in the last three decades however has been advocating the measurement of outcomes from the patient's perspective using Health-Related Quality of Life questionnaires (HRQOL). Although several generic and region-specific HRQOL questionnaires exist, there is no guidance as to which one is the most appropriate for this population. The objective of this study is to evaluate the psychometric properties of three self-reported HRQOL outcome measures in patients with DD.

METHODS

Patients with DD were enrolled from the practices of three plastic surgeons. Test-retest reliability, concurrent validity and responsiveness of three HRQOL questionnaires were compared in a prospective study design. The HRQOL measures included Health Utilities Index Mark 3 (HUI3), Short Form-36 (SF-36), and the Michigan Hand Questionnaire (MHQ).

RESULTS

All three measures demonstrated good test-retest reliability (ICC = 0.77-0.85). Concurrent validity was found between the HUI3 pain and dexterity attributes and SF-36 physical summary score. The sensitivity of the MHQ to detect changes in the status of the patient was found to be high (effect size = 1.14) whereas that of the SF-36 was trivial.

CONCLUSIONS

The HUI3 and the MHQ seem to be reliable and valid tools to assess the HRQOL in patients with Dupuytren's Disease.

Down-regulation of collagen synthesis and matrix metalloproteinase expression in myofibroblasts from Dupuytren nodule using adenovirus-mediated relaxin gene therapy

Dupuytren's disease is a fibroproliferative connective tissue disorder characterized by contracture of the palmer fascia of the hand. Relaxin (RLN) is a multifunctional factor which contributes to the remodeling of the pelvic ligament by inhibiting fibrosis and inflammatory activities. The aim of this study was to investigate the effect of the RLN gene on the inhibition of fibrosis in myofibroblastic cells. Myofibroblast cells with adenovirus LacZ (Ad-LacZ) as a marker gene or adenovirus relaxin (Ad-RLN) as therapeutic gene showed transgene expressions in beta-galactosidase assay and Western blot analysis. Myofibroblastic cells with Ad-RLN demonstrated a 22% and 48% reduction in collagen I and III mRNA expressions respectively, a 50% decrease in MMP-1, 70% decrease in MMP-2, 80% decrease in MMP-9, and a 15% reduction in MMP-13 protein expression compared with cultures with viral control and saline control. In addition, myofibroblastic cells with Ad-RLN showed a 40% decrease in TIMP 1 and a 15% increase in TIMP 3 protein expression at 48 h compared to cultures with viral control and saline control. Also, myofibroblastic cell with Ad-RLN demonstrated a 74% inhibition of fibronectin and a 52% decrease in total collagen synthesis at 48 h compared with cultures with viral control and saline control. In conclusion, the RLN gene render antifibrogenic effect on myofibroblastic cells from Dupuytren's nodule via direct inhibition of collagen synthesis not through collagenolytic pathway such as MMP-1, -13, TIMP 1, and 3. Therefore relaxin can be an alternative therapeutic strategy in initial stage of Dupuytren's disease by its antifibrogenic effect.

URAM scale for functional assessment in Dupuytren's disease: a comparative study of its properties

OBJECTIVE

To test the convergent validity and ease of use of the Unité Rhumatologique des Affections de la Main (URAM) scale for patients with Dupuytren's disease.

METHODS

Patients were prospectively included. We compared the convergent validity of the URAM scale, the Cochin Hand Function Scale (CHFS) and the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, in terms of their correlation with the Tubiana score and self-assessed disability on a visual analog scale (VAS). Pearson's correlation was used for the convergent validity study. The response time for questionnaire completion was the outcome for ease of implementation.

RESULTS

We included 53 patients with Dupuytren's disease in the convergent validity study and 30 other patients with the disease in the time-response assessment. The URAM scale showed strong convergence with the Tubiana scale (r=0.64) and self-assessed disability on a VAS (r=0.69). Convergence with the Tubiana and self-assessed disability was higher for the URAM scale than the CHFS or DASH questionnaire. The mean [SD] response time was shorter for the URAM scale than the CHFS or DASH questionnaire (42 [20] vs 71 [35] and 103 [59] s, respectively, P<0.0001).

CONCLUSIONS

The results reinforce the psychometric merits of the URAM scale. Furthermore, the response time for assessing disability was shorter with the URAM scale than the CHFS or DASH questionnaire. This evidence supports the high recommendation for the use of the URAM scale in clinical practice and clinical studies to assess disability in Dupuytren's disease.

Dermatologic manifestations of diabetes mellitus: a review

Diabetes mellitus affects every organ of the body including the skin. Certain skin manifestations of diabetes are considered cutaneous markers of the disease, whereas others are nonspecific conditions that occur more frequently among individuals with diabetes compared with the general population. Diabetic patients have an increased susceptibility to some bacterial and fungal skin infections, which account, in part, for poor healing. Skin complications of diabetes provide clues to current and past metabolic status. Recognition of cutaneous markers may slow disease progression and ultimately improve the overall prognosis by enabling earlier diagnosis and treatment.

Dupuytren's Contracture Cosegregation with Limb-Girdle Muscle Dystrophy

Limb-girdle muscular dystrophies (LGMDs) is a heterogeneous group of muscular dystrophies that mostly affect the pelvic and shoulder girdle muscle groups. We report here a case of neuromuscular disease associated with Dupuytren's contracture, which has never been described before as cosegregating with an autosomal dominant type of inheritance. Dupuytren's contracture is a common disease, especially in Northern Europe. Comorbid conditions associated with Dupuytren's contracture are repetitive trauma to the hands, diabetes, and seizures, but it has never before been associated with neuromuscular disease. We hypothesize that patients may harbor mutations in genes with functions related to neuromuscular disease and Dupuytren's contracture development.

Increased CCT-eta expression is a marker of latent and active disease and a modulator of fibroblast contractility in Dupuytren's contracture

Dupuytren's contracture (DC) is a fibroproliferative disorder of unknown etiology characterized by a scar-like contracture that develops in the palm and/or digits. We have previously reported that the eta subunit of the chaperonin containing T-complex polypeptide (CCT-eta) is increased in fibrotic wound healing, and is essential for the accumulation of α-smooth muscle actin (α-SMA) in fibroblasts. The purpose of this study was to determine if CCT-eta is similarly implicated in the aberrant fibrosis seen in DC and to investigate the role of CCT-eta in the behavior of myo/fibroblasts in DC. Fibroblasts were obtained from DC-affected palmar fascia, from adjacent phenotypically normal palmar fascia in the same DC patients (PF), and from non-DC palmar fascial tissues in patients undergoing carpal tunnel (CT) release. Inherent contractility in these three populations was examined using fibroblast-populated collagen lattices (FPCLs) and by cell traction force microscopy. Expression of CCT-eta and α-SMA protein was determined by Western blot. The effect of CCT-eta inhibition on the contractility of DC cells was determined by deploying an siRNA versus CCT-eta. DC cells were significantly more contractile than both matching palmar fascial (PF) cells and CT cells in both assays, with PF cells demonstrating an intermediate contractility in the FPCL assay. Whereas α-SMA protein was significantly increased only in DC cells compared to PF and CT cells, CCT-eta protein was significantly increased in both PF and DC cells compared to CT cells. siRNA-mediated depletion of CCT-eta inhibited the accumulation of both CCT-eta and α-SMA protein in DC cells, and also significantly decreased the contractility of treated DC cells. These observations suggest that increased expression of CCT-eta appears to be a marker for latent and active disease in these patients and to be essential for the increased contractility exhibited by these fibroblasts.

Common variants of the ALDH2 and DHDH genes and the risk of Dupuytren's disease

The object of this study was the investigation of four common variants of single nucleotide polymorphisms of the aldehyde dehydrogenase H2 gene and dihydrodiol dehydrogenase gene and their association with the occurrence of Dupuytren's disease. DNA samples were obtained from the peripheral blood of 300 consecutive patients. The control group comprised 300 healthy adults who were age matched with the Dupuytren's patients. All four common variants were analysed using TaqMan® genotyping assays and sequencing. The differences in the frequencies of variants of single nucleotide polymorphisms in patients and the control group were statistically tested. No significant differences were found in the frequencies of the variants of the aldehyde dehydrogenase H2 and dihydrodiol dehydrogenase genes between the groups. Likewise, no significant differences were found in the frequencies of the variants of the genes between men and women. We noted a statistically significantly higher prevalence of the variants of the dihydrodiol dehydrogenase gene (rs2270941 and rs11666105) in the group with a positive familial history of Dupuytren's disease, in comparison with the group with a negative familial history.

Dupuytren's Contracture in Alabama HFE Hemochromatosis Probands

BACKGROUND

Dupuytren's contracture (DC) and HFE hemochromatosis occur in some of the same at-risk populations and present with similar comorbid conditions.

METHODS

We estimated DC prevalence in two cohorts of white Alabama hemochromatosis probands (294 C282Y homozygotes, 67 C282Y/H63D compound heterozygotes) in a retrospective study. We performed logistic regressions on DC using the following independent variables: age, body mass index, heavy ethanol consumption, serum ferritin, elevated serum AST/ALT, non-alcoholic fatty liver disease, viral hepatitis, cirrhosis, and diabetes.

RESULTS

One man and two women with C282Y homozygosity had DC (prevalence 1.02%; 95% CI 0.35%-2.96%). A man with C282Y/H63D had DC (prevalence 1.49%; 95% CI 0.26%-7.98%). DC occurred as an autosomal dominant trait in his kinship. In regression analyses, no single variable predicted DC. We observed no new DC cases after the diagnosis of hemochromatosis (mean follow-up 12.9 ± 7.5 years (1 SD), and 9.0 ± 5.1 years, respectively).

CONCLUSIONS

Our prevalence estimates of DC in white Alabama hemochromatosis probands are similar to those found in the white US population cohorts. DC risk was unrelated to the variables we studied.

Evaluation of a mitochondrial DNA mutation in maternally inherited and sporadic cases of Dupuytren disease

OBJECTIVE

The purpose was to test the hypothesis that Dupuytren disease (DD) is associated with a previously reported mutation in mitochondrial DNA at position 2839.

METHODS

Two hundred sixty-nine cases of DD and an equal number of matched controls were identified in Marshfield Clinic's Personalized Medicine Research Project (PMRP). Clinical data used to describe the cohort were abstracted from the electronic medical records of the population. Genetic analysis of all the cases and controls was done using a custom synthesis TaqMan assay, while genetic analysis of sixteen of the above cases with a familial history of DD was performed by mitochondrial DNA sequencing at position C2839A.

RESULTS

Cases and controls were evenly distributed with 167 (62%) men and 102 (38%) women. The majority, 264 (98%) of the cases and controls were white non-Hispanic. Of the 269 cases, 16 were found to have a familial history of DD. Two cases had a maternal history, eight a paternal history, five an affected sibling, and one a paternal grandfather. All cases and controls were found to have only the C allele at the site of the reported mitochondrial C2839A polymorphism.

CONCLUSIONS

The previously reported mitochondrial mutation was not present in our small, maternally inherited cohort or in the total population of 538 cases and controls. This finding does not support the reported incidence of this polymorphism in 90% of the affected population with a maternal inheritance, and calls into question the role of the C2839A mitochondrial DNA polymorphism in familial or sporadic cases of DD.