A genealogical assessment of heritable predisposition to asthma mortality

The Asthma Family Tree: Evaluating Associations Between Childhood, Parental, and Grandparental Asthma in Seven Chinese Cities

Objective: To evaluate the associations between childhood, parental, and grandparental asthma. Methods: We studied 59,484 children randomly selected from 94 kindergartens, elementary, and middle schools in seven Chinese cities from 2012 to 2013, using a cross-sectional survey-based study design. Information on their and their family members' (parents, paternal grandparents, and maternal grandparents) asthma status were reported by children's parents or guardians. Mixed effects logistic regressions were used to assess hereditary patterns of asthma and mediation analysis was performed to estimate the potential mediation effect of parents on the association between grandparental asthma and childhood asthma. Results: The magnitude of ORs for childhood asthma increased as the number of family members affected by asthma increased. Among children who had one family member with asthma, childhood asthma was associated with asthma in maternal grandmothers (OR: 2.08, 95% CI: 1.67-2.59), maternal grandfathers (OR: 2.08, 95% CI: 1.71-2.53), paternal grandmothers (OR: 2.40, 95% CI: 1.93-2.99), and paternal grandfathers (OR: 2.59, 95% CI: 2.14-3.13). Among children who had two family members with asthma, the highest asthma risk was found when both parents had asthma (OR: 15.92, 95% CI: 4.66-54.45). Parents had a small proportion of mediation effect (9-12%) on the association between grandparental asthma and childhood asthma. Conclusions: Grandparents with asthma were associated with childhood asthma and parents with asthma partially mediated the association.

Population genealogy resource shows evidence of familial clustering for Alzheimer disease

OBJECTIVE

To show the potential of a resource consisting of a genealogy of the US record linked to National Veterans Health Administration (VHA) patient data for investigation of the genetic contribution to health-related phenotypes, we present an analysis of familial clustering of VHA patients diagnosed with Alzheimer disease (AD).

METHODS

Patients with AD were identified by the International Classification of Diseases code. The Genealogical Index of Familiality method was used to compare the average relatedness of VHA patients with AD with expected relatedness. Relative risks for AD were estimated in first- to fifth- degree relatives of patients with AD using population rates for AD.

RESULTS

Evidence for significant excess relatedness and significantly elevated risks for AD in relatives was observed; multiple pedigrees with a significant excess of VHA patients with AD were identified.

CONCLUSIONS

This analysis of AD shows the nascent power of the US Veterans Genealogy Resource, in early stages, to provide evidence for familial clustering of multiple phenotypes, and shows the utility of this VHA genealogic resource for future genetic studies.

Evidence of an Inherited Predisposition for Spinal Cord Tumors

STUDY DESIGN

Retrospective study.

OBJECTIVES

To determine familial clustering of primary spinal cord tumors using a statewide genealogy database.

METHODS

The Utah Population Database (UPDB) was queried using ICD-Oncology (International Classification of Diseases for Oncology) codes for primary spinal cord tumors. The hypothesis of disproportionate familial clustering was tested using the Genealogical Index of Familiality (GIF). The relative risks (RRs) in relatives were calculated using the ratio of observed spinal cord tumors to expected spinal cord tumors in relatives using estimated rates from the UPDB. The related clusters of spinal cord cancer cases with a significant excess number of spinal cord cancer cases descending from a common founder pair were identified using internal UPDB rates.

RESULTS

The analysis of the GIF for individual with tumors of the spinal cord showed excess close and distant relatedness (case GIF = 3.82; control mean GIF = 2.68; P = .068). Excess relatedness for spinal cord cancers was observed when only more distant relationships were considered (P = .019). The RRs for spinal cord tumors were elevated in second- and third-degree relatives but this did not reach statistical significance (RR = 2.9, P = .15, and RR = 2.0, P = .14). Multiple extended pedigrees with a significant excess of spinal cord cancer cases among the descendants were identified.

CONCLUSIONS

The excess relatedness of tumor cases over controls in distant relationships, the higher RRs to distant relatives, and the discovery of high-risk pedigrees all suggest a familial predisposition to the development of spinal cord tumors.

Genetic Contribution to Nonsquamous, Non-Small Cell Lung Cancer in Nonsmokers

INTRODUCTION

Lung carcinogenesis is strongly influenced by environmental and heritable factors. The genetic contribution to the different histologic subtypes is unknown.

METHODS

A population-based computerized genealogy resource linked to a statewide cancer registry of lung cancer cases (N = 5408) was analyzed to evaluate the heritable contribution to lung cancer histologic subtype in smokers (n = 1751) and nonsmokers (n = 818). Statistical methods were used to test for significant excess relatedness of lung cancer cases.

RESULTS

Significant excess distant relatedness was observed for all lung cancer histologic subgroups analyzed except for the SCLC subset (p = 0.213). When histologic subsets of smokers and nonsmokers with lung cancer were considered, excess relatedness was observed only in nonsmokers with NSCLC (n = 653 [p = 0.026]) and, in particular, in those nonsmokers with the nonsquamous histologic subtype (n = 561 [p = 0.036]). A total of 61 pedigrees demonstrating a significant excess risk of nonsquamous lung cancer in nonsmokers were identified, and an excess of cases in females was observed among the individuals with these high-risk pedigrees.

CONCLUSIONS

This analysis supports a genetic predisposition to lung cancer carcinogenesis in nonsmokers with nonsquamous NSCLC.

Near-fatal asthma: a heterogeneous clinical entity

PURPOSE OF REVIEW

The aims of the present review were to describe the heterogeneous nature of near-fatal asthma (NFA) and to summarize the distinctive phenotypes identified in this subtype of asthma.

RECENT FINDINGS

Clinical, physiological, and histological studies have shown a large number of triggers, pathological mechanisms, and risk factors associated with NFA. Based on the demographic and clinical characteristics of the patients, the circumstances surrounding the asthma exacerbation and some distinctive features of the disease, several clinical profiles of asthma patients with NFA have been described. Recent data show new associations between some gene expression patterns and fatal asthma, as well as with some biological markers related to inflammatory or immunologic mechanisms in the airways. Also, the use of statistical methods, such as cluster analysis, allowed identifying and confirming different phenotypes of life-threatening asthma patients.

SUMMARY

NFA is a heterogeneous clinical entity, in which different patients' clinical profiles may coexist [e.g. rapid-onset NFA, NFA in patients with dyspnea hypoperception or sensitized to certain pneumoallergens (Alternaria alternata, soybean), NFA related to the menstrual cycle, brittle asthma]. Knowledge of these phenotypes as well as adequate and specific management strategies can reduce morbidity and mortality in patients suffering from NFA.

Mortality risk in patients with chronic rhinosinusitis and its association to asthma

BACKGROUND

Chronic rhinosinusitis (CRS) is a highly prevalent inflammatory condition, with significant effects on morbidity and quality of life. Given that other chronic inflammatory conditions have been associated with increased mortality risk, we sought to evaluate the relationship between mortality and CRS including the influence of asthma. Our objective was to determine if CRS, with or without asthma, is associated with altered risk of mortality.

METHODS

Using a statewide population database, we retrospectively identified 27,005 patients diagnosed with CRS between 1996 and 2012, and 134,440 unaffected controls matched 5:1 on birth year and sex. Risk of mortality was determined from Cox models and Kaplan-Meier curves were used to compare survival.

RESULTS

A significant interaction between CRS and asthma status was observed in which CRS appeared to confer a protective effect in asthma patients. Asthma, when present, increased mortality in CRS-negative controls (p-interaction < 0.0001). Independent of asthma status, CRS patients exhibited a decreased mortality risk (hazard ratio [HR] = 0.80; 95% confidence interval [CI], 0.74 to 0.85) compared to controls. However, in patients diagnosed at or before the median age of CRS onset (42 years) independent of asthma status, survival was not improved (HR = 0.98; 95% CI, 0.81 to 1.18). Risk of mortality was greater in CRS with nasal polyps (n = 1643) compared to 25,362 polyp-negative CRS patients (HR = 1.38; 95% CI, 1.09 to 1.77).

CONCLUSION

CRS was associated with lower risk of mortality compared to controls, and appeared to mitigate increased mortality from asthma. We posit that better survival conferred by CRS may be secondary to treatment. However, the etiology of this relationship and the effect of CRS treatment on mortality are unknown.

Evidence for an Environmental and Inherited Predisposition Contributing to the Risk for Global Tendinopathies or Compression Neuropathies in Patients With Rotator Cuff Tears

Background:

Rotator cuff tearing has been found to be clinically associated with other tendinopathies and compression neuropathies; a significant excess of these phenotypes has been seen in patients with rotator cuff tears. It is unclear if the association is secondary to environmental or genetic influences.

Purpose:

To examine population-based data for comorbid association of rotator cuff tearing and tendinopathies and compression neuropathies and to determine whether the association extends to relatives of patients with rotator cuff tears, which could suggest a genetic contribution.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

The Utah Population Database (UPDB) contains health and genealogical data on over 2 million Utah residents. Current Procedural Terminology, Fourth Revision, codes (CPT 4) and International Classification of Diseases, Ninth Revision, codes (ICD-9) entered in patient records were used to identify patients with rotator cuff tearing and with comorbid tendinopathies and compression neuropathies. We tested the hypothesis of excess familial clustering of these other phenotypes with rotator cuff tearing using a well-established method (estimation of relative risks) in the overall study group of rotator cuff patients (N = 1889).

Results:

Significantly elevated risk for elbow, hand/wrist, foot/ankle, knee, and hip tendinopathies, as well as for all tendinopathies and compression neuropathies, was observed in rotator cuff tear cases themselves (P < 2.8e^–13), in their spouses (P < .02), and in their first-degree relatives (P < 5.5e^–4). A significant excess of elbow (P = .01), foot/ankle (P = .04), and all tendinopathies (P = 3.1e^–3) was also observed in second-degree relatives, and a significant excess of compression neuropathies (P = .03) was observed in third-degree relatives.

Conclusion:

The current study shows strong evidence of familial clustering of rotator cuff tearing with other tendinopathies and with compression neuropathy. Observed increased risks in spouses and first-degree relatives supports shared environmental risk factors for rotator cuff tearing, most tendinopathies, and compression neuropathies. Increased risks to third-degree relatives for compression neuropathy suggest an association of these phenotypes that may have a shared genetic etiology.

Familial aggregation of Parkinson disease in Utah: A population-based analysis using death certificates

Objective:

To describe clustering of death from Parkinson disease (PD) in relatives in a large US study.

Methods:

We analyzed the Utah Population Database resource, which includes genealogy data of more than 2.7 million individuals linked to 519,061 individuals with a Utah death certificate (DC). We identified individuals whose DC included PD as a cause of death using ICD coding. In those individuals whose Utah DC listed PD as a cause of death, the relative risk (RR) of death with PD was determined among close and distant relatives using sex-, birth year–, and birthplace-specific rates.

Results:

We identified 4,031 individuals whose DC indicated PD. Among 18,127 first-degree relatives of probands with a Utah DC, the RR of death with PD was significantly increased (RR = 1.82, 95% confidence interval [CI] 1.61–2.04). The RR of death with PD was also significantly increased among 40,546 second-degree relatives with a Utah DC (RR = 1.44, 95% CI 1.29–1.60) and among 93,398 third-degree relatives with a Utah DC (RR = 1.10, 95% CI 1.03–1.18).

Conclusions:

Significant evidence for excess familial clustering was observed for PD deaths. The excess familial clustering and the significantly elevated RRs for PD among close and distant relatives strongly support a genetic contribution to PD mortality. These results confirm and expand the results of previous studies of PD by quantifying the risk of PD death among more distant relatives.

A Heritable Predisposition to Osteoarthritis of the Hip

Using THA as a proxy for underlying osteoarthritis, we describe population-based familial clustering of osteoarthritis of the hip. The GIF test for excess relatedness on 1049 patients that underwent THA (and do not have a diagnostic code for other conditions leading to THA) showed excess relatedness (P<0.001). Even when close relationships were ignored (closer than third-degree relationships), excess relatedness was observed (P=0.020). Relative risk was elevated in first-degree (RR 2.59; 95% CI 1.84-3.53, P=2.0e(-7)), second-degree (RR 1.66; 95% CI 1.11-2.39; P=0.0075) and third-degree relatives (RR 1.46; 95% CI 1.17-1.81; P=5.7e(-4)). Excess relatedness of individuals who had undergone THA for osteoarthritis and elevated risks to both near and distant relatives were observed.

Genetic analysis of low BMI phenotype in the Utah Population Database

The low body mass index (BMI) phenotype of less than 18.5 has been linked to medical and psychological morbidity as well as increased mortality risk. Although genetic factors have been shown to influence BMI across the entire BMI, the contribution of genetic factors to the low BMI phenotype is unclear. We hypothesized genetic factors would contribute to risk of a low BMI phenotype. To test this hypothesis, we conducted a genealogy data analysis using height and weight measurements from driver's license data from the Utah Population Data Base. The Genealogical Index of Familiality (GIF) test and relative risk in relatives were used to examine evidence for excess relatedness among individuals with the low BMI phenotype. The overall GIF test for excess relatedness in the low BMI phenotype showed a significant excess over expected (GIF 4.47 for all cases versus 4.10 for controls, overall empirical p-value<0.001). The significant excess relatedness was still observed when close relationships were ignored, supporting a specific genetic contribution rather than only a family environmental effect. This study supports a specific genetic contribution in the risk for the low BMI phenotype. Better understanding of the genetic contribution to low BMI holds promise for weight regulation and potentially for novel strategies in the treatment of leanness and obesity.

Strong evidence for a genetic contribution to late-onset Alzheimer's disease mortality: a population-based study

BACKGROUND

Alzheimer's disease (AD) is an international health concern that has a devastating effect on patients and families. While several genetic risk factors for AD have been identified much of the genetic variance in AD remains unexplained. There are limited published assessments of the familiality of Alzheimer's disease. Here we present the largest genealogy-based analysis of AD to date.

METHODS

We assessed the familiality of AD in The Utah Population Database (UPDB), a population-based resource linking electronic health data repositories for the state with the computerized genealogy of the Utah settlers and their descendants. We searched UPDB for significant familial clustering of AD to evaluate the genetic contribution to disease. We compared the Genealogical Index of Familiality (GIF) between AD individuals and randomly selected controls and estimated the Relative Risk (RR) for a range of family relationships. Finally, we identified pedigrees with a significant excess of AD deaths.

RESULTS

The GIF analysis showed that pairs of individuals dying from AD were significantly more related than expected. This excess of relatedness was observed for both close and distant relationships. RRs for death from AD among relatives of individuals dying from AD were significantly increased for both close and more distant relatives. Multiple pedigrees had a significant excess of AD deaths.

CONCLUSIONS

These data strongly support a genetic contribution to the observed clustering of individuals dying from AD. This report is the first large population-based assessment of the familiality of AD mortality and provides the only reported estimates of relative risk of AD mortality in extended relatives to date. The high-risk pedigrees identified show a true excess of AD mortality (not just multiple cases) and are greater in depth and width than published AD pedigrees. The presence of these high-risk pedigrees strongly supports the possibility of rare predisposition variants not yet identified.

Use of a genealogical database demonstrates heritability of pulmonary fibrosis

BACKGROUND

Pulmonary fibrosis (PF) is a progressive fatal disease of unknown etiology. Identification of risk genes and pathways will enhance our understanding of this disease. Analysis of Utah genealogical resources has shown previously strong evidence for a genetic contribution to other disease, such as cancer. This approach has led to gene discovery in diseases, such as breast cancer and colon cancer and is used here for PF to quantify the heritability.

HYPOTHESIS

We hypothesize that there is a heritable contribution to death from PF and use existing genealogic and death certificate data to examine patterns of relatedness amongst individuals who have died of PF.

METHODS

We analyzed familial clustering of individuals who died from PF using the Utah Population Database, a unique population-based genealogical resource that has been linked to death certificates dating from 1904. We identified 1,000 individuals with at least three generations of genealogy data and a cause of death documented as PF (cases). We estimated the relative risk (RR) of death from PF among the first-, second-, and third-degree relatives of cases. We also tested the hypothesis of excess relatedness among the cases by comparing the average pairwise relatedness of all cases to the average pair-wise relatedness of 1,000 sets of matched controls.

RESULTS

We observed significantly increased risk for death from PF among the first- (RR = 4.69), second- (RR = 1.92), and third-degree relatives (RR = 1.14) of cases. The average relatedness of the 1,000 cases was significantly higher than the expected average relatedness of matched control sets (p < 0.001). When close (first- and second-degree) relationships were ignored, significantly increased relatedness remained (p = 0.002).

CONCLUSIONS

Our results demonstrate significant clustering among both close and distant relatives, providing strong support for genetic contributions to death from PF. High-risk pedigrees derived from this unique resource may help identify new risk genes and gene pathways.

Empiric evidence for a genetic contribution to predisposition to surgical site infection

The genetics of microbial pathogens have been extensively studied, but there has been little work on human genetic susceptibility to surgical site infection (SSI). We analyzed a large genealogical population database to study the familial contribution to SSI. We analyzed 651 individuals with International Classification of Disease, Ninth Revision codes indicating the presence of SSI. Matched hospital controls were randomly selected from the database based on birth year, sex, and birthplace. The average relatedness of all possible pairs of cases and separately of controls (×1000 sets) was compared empirically. The relative risk (RR) for SSI was estimated by comparing the number of observed affected individuals among the relatives of cases to the number of affected individuals observed among relatives of matched hospital controls. The genealogical index of familiality test for patients with SSI showed significant excess relatedness (p < 0.010); this excess was still observed when close relationships were ignored (p =  0.019). The RR for third-degree relatives of cases was significantly elevated (1.62, p = 0.029). The significant excess relatedness and the significantly elevated RR to distant relatives support a genetic predisposition to acquiring SSI.

Creation of a national resource with linked genealogy and phenotypic data: the Veterans Genealogy Project

PURPOSE

Creation of a genealogy of the United States and its ancestral populations is under way. When complete, this US genealogy will be record linked to the National Veteran's Health Administration medical data representing more than 8 million US veterans.

METHODS

Genealogical data are gathered from public sources, primarily the Internet. Record linking using data from relatives is accomplished to integrate multiple data sources and then to link genealogical data to the veteran's demographic data.

RESULTS

This resource currently includes genealogy for more than 22 million individuals representing the Intermountain West and the East Coast. The demographic data for more than 40,000 veteran patients using Veterans Hospital Administration services in Utah and Massachusetts have already been record linked.

CONCLUSION

The resource is only in its second year of creation and already represents the largest such combination of genealogy and medical data in the world. The data sources, the creation of the genealogy, record-linking methods and results, proposed genetic analyses, and future directions are discussed.

A comprehensive survey of cancer risks in extended families

PURPOSE

Cancer is familial; yet known cancer predisposition genes, as well as recognized environmental factors, explain only a small percentage of familial cancer clusters. This population-based description of cancer clustering describes patterns of cancer coaggregation suggestive of a genetic predisposition.

METHODS

Using a computerized genealogy of Utah families linked to a statewide cancer registry, we estimated the relative risks for 36 different cancer sites in first-, second-, and third-degree relatives of cancer cases, for each cancer site individually, and between cancer sites. We estimated the sex- and birth-year-specific rates for cancer using 1 million individuals in the resource. We applied these rates to groups of cases or relatives and compared the observed and expected numbers of cancers to estimate relative risks.

RESULTS

Many cancer sites show significantly elevated relative risks among distant relatives for cancer of the same site, strongly supporting a heritable contribution. Multiple combinations of cancer sites were observed among first-, second-, and third-degree relatives, suggesting the existence of heritable syndromes involving more than one cancer site.

CONCLUSION

This complete description of coaggregation of cancer by site in a well-defined population provides a set of observations supporting heritable cancer predispositions and may support the existence of genetic factors for many different cancers.

Evidence of an inherited predisposition for cervical spondylotic myelopathy

STUDY DESIGN

A retrospective, population-based study cross-referencing a genealogic database of over 2 million Utah residents with 10 years of clinical diagnosis data from a large tertiary hospital.

OBJECTIVE

The objective of this study is to determine the presence or absence of an inherited predisposition to the development of cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

A genetic predisposition for the development of cervical spondylosis has been discussed in the literature with low-quality evidence. Families with a high incidence of disease or early-onset disease in monozygotic twins have both been reported. However, these suggestions of an inherited predisposition for disease have never been rigorously studied. The purpose of this study is to determine a genetic predisposition among patients diagnosed with CSM.

METHODS

The Utah Population Database combines health and genealogic data on over 2 million Utah residents. International Classification of Diseases, Ninth Revision (ICD-9) codes were used to identify 486 patients in the database with a diagnosis of CSM (ICD-9 code 721.1). The hypothesis of excessive familial clustering was tested using the Genealogical Index of Familiality (GIF), and relative risks (RRs) in relatives were estimated by comparing rates of disease in relatives with rates estimated in the relatives of five matched controls for each case. This methodology has been previously reported and validated for other disease conditions but not for CSM.

RESULTS

The GIF analysis for patients with CSM showed significant excess relatedness for disease (P < 0.001). RRs were significantly elevated in both first- (RR = 5.21, CI = 2.1-13.2, P < 0.001) and third-degree relatives (RR = 1.95, CI = 1.04-3.7, P < 0.05).

CONCLUSION

Excess relatedness of cases and significantly elevated RRs to both close and distant relatives supports an inherited predisposition to CSM.

Significant evidence for a heritable contribution to cancer predisposition: a review of cancer familiality by site

BACKGROUND/AIMS

Sound and rigorous well-established, and newly extended, methods for genetic epidemiological analysis were used to analyze population evidence for genetic contributions to risk for numerous common cancer sites in Utah. The Utah Population Database (UPDB) has provided important illumination of the familial contribution to cancer risk by cancer site.

METHODS

With over 15 years of new cancer data since the previous comprehensive familial cancer analysis, we tested for excess familial clustering using an expanded Genealogical Index of Familiality (dGIF) methodology that provides for a more informative, but conservative test for the existence of a genetic contribution to familial relatedness in cancer.

RESULTS

Some new cancer sites have been analyzed for the first time, having achieved sufficiently large sample size with additions to the UPDB. This new analysis has identified 6 cancer sites with significant evidence for a heritable contribution to risk, including lip, chronic lymphocytic leukemia, thyroid, lung, prostate, and melanoma.

CONCLUSIONS

Both environmentally and genetically-based familial clustering have clinical significance, and these results support increased surveillance for cancer of the same sites among close relatives of affected individuals for many more cancers than are typically considered.

Asthma mortality in Serbia: a 30-year analysis

INTRODUCTION

The asthma mortality pattern differs among countries. No published evidence is currently available on asthma mortality in a European low-middle-income country in socioeconomic transition. We analyzed the trend of asthma mortality rate in Serbia during the period 1980-2009.

MATERIALS AND METHODOLOGY

a descriptive study; source of data: Republic of Serbia Institute of Statistics Death Registry. We analyzed asthma mortality data in the total population, including gender specific analysis, and in the selected ≥ 5-34 year age group. The International Classification of Diseases codes for asthma 493 (1980-1996) and J45 + J46 (1997-2009) were included. Population estimates were based on 1991 and 2002 census data, with extrapolation.

RESULTS

The over-all average mortality rate was 7.27 ± 2.14/100,000 inhabitants. The mortality rate peaked in 1981 at 11.3/100,000 but was 4.45/100,000 in the last year of analysis. While both overall mortality rate, as well as gender specific rates, showed clear decreases over the observed 30-year period (average absolute annual decrease of 0.195/100,000 inhabitants, 0.241/100,000 men and 0.149/100,000 women; p < 0.001) with corresponding relative annual decreases of 2.9% for the whole population, 3.0% for men and 2.8% for women, a stable trend of the rate was found in the age group ≥ 5-34 years. Male-to-female ratio was 1.59 ± 0.186, on average and it showed a stable trend over the observed period.

CONCLUSION

Although the failure of the health care system during the socioeconomic crisis of the 1990s might have transiently affected asthma mortality rates, the overall mortality rate for the disease shows a favorable decreasing trend.

Evidence of an inherited predisposition for cervical spondylotic myelopathy

STUDY DESIGN

A retrospective, population-based study cross-referencing a genealogic database of over 2 million Utah residents with 10 years of clinical diagnosis data from a large tertiary hospital.

OBJECTIVE

The objective of this study is to determine the presence or absence of an inherited predisposition to the development of cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

A genetic predisposition for the development of cervical spondylosis has been discussed in the literature with low-quality evidence. Families with a high incidence of disease or early-onset disease in monozygotic twins have both been reported. However, these suggestions of an inherited predisposition for disease have never been rigorously studied. The purpose of this study is to determine a genetic predisposition among patients diagnosed with CSM.

METHODS

The Utah Population Database combines health and genealogic data on over 2 million Utah residents. International Classification of Diseases, Ninth Revision (ICD-9) codes were used to identify 486 patients in the database with a diagnosis of CSM (ICD-9 code 721.1). The hypothesis of excessive familial clustering was tested using the Genealogical Index of Familiality (GIF), and relative risks (RRs) in relatives were estimated by comparing rates of disease in relatives with rates estimated in the relatives of five matched controls for each case. This methodology has been previously reported and validated for other disease conditions but not for CSM.

RESULTS

The GIF analysis for patients with CSM showed significant excess relatedness for disease (P < 0.001). RRs were significantly elevated in both first- (RR = 5.21, CI = 2.1-13.2, P < 0.001) and third-degree relatives (RR = 1.95, CI = 1.04-3.7, P < 0.05).

CONCLUSION

Excess relatedness of cases and significantly elevated RRs to both close and distant relatives supports an inherited predisposition to CSM.

Evidence for a heritable predisposition to Chronic Fatigue Syndrome

Background

Chronic Fatigue Syndrome (CFS) came to attention in the 1980s, but initial investigations did not find organic causes. Now decades later, the etiology of CFS has yet to be understood, and the role of genetic predisposition in CFS remains controversial. Recent reports of CFS association with the retrovirus xenotropic murine leukemic virus-related virus (XMRV) or other murine leukemia related retroviruses (MLV) might also suggest underlying genetic implications within the host immune system.

Methods

We present analyses of familial clustering of CFS in a computerized genealogical resource linking multiple generations of genealogy data with medical diagnosis data of a large Utah health care system. We compare pair-wise relatedness among cases to expected relatedness in the Utah population, and we estimate risk for CFS for first, second, and third degree relatives of CFS cases.

Results

We observed significant excess relatedness of CFS cases compared to that expected in this population. Significant excess relatedness was observed for both close (p <0.001) and distant relationships (p = 0.010). We also observed significant excess CFS relative risk among first (2.70, 95% CI: 1.56-4.66), second (2.34, 95% CI: 1.31-4.19), and third degree relatives (1.93, 95% CI: 1.21-3.07).

Conclusions

These analyses provide strong support for a heritable contribution to predisposition to Chronic Fatigue Syndrome. A population of high-risk CFS pedigrees has been identified, the study of which may provide additional understanding.

Evidence for an inherited predisposition to lumbar disc disease

BACKGROUND

A genetic predisposition for the development of symptomatic lumbar disc disease has been suggested by several twin sibling studies and subsequent genetic marker studies. The purpose of the present study was to define population-based familial clustering among individuals with a diagnosis of, or treated for, lumbar disc herniation or disc degeneration.

METHODS

The Utah Population Database allows analysis of combined health and genealogic data for over one million Utah residents. We used the International Classification of Diseases, Ninth Revision, diagnosis codes entered in patient records to identify patients with a diagnosis of either lumbar disc herniation or lumbar disc degeneration and genealogic data. The hypothesis of excess relatedness (familial clustering) was tested with use of the Genealogical Index of Familiality, which compares the average relatedness of affected individuals with expected population relatedness. Relative risks in relatives were estimated by comparing rates of disease in relatives with expected population rates (estimated from the relatives of matched controls). This methodology has been previously reported for other disease conditions but not for spinal diseases.

RESULTS

The Genealogical Index of Familiality test for 1264 patients with lumbar disc disease showed a significant excess relatedness (p < 0.001). Relative risk in relatives was significantly elevated in both first-degree (relative risk, 4.15; p < 0.001) and third-degree relatives (relative risk, 1.46; p = 0.027).

CONCLUSIONS

Excess relatedness of affected individuals and elevated risks to both near and distant relatives was observed, strongly supporting a heritable contribution to the development of symptomatic lumbar disc disease.

[Adult asthma exacerbations in questions]

In this article a French working party critically review the international literature to revise the definition, pathophysiology, treatment and cost of exacerbations of adult asthma. The various guidelines do not always provide a consistent definition of exacerbations of asthma. An exacerbation can be defined as deterioration of clinical and/or functional parameters lasting more than 24 hours, without return to baseline, requiring a change of treatment. No single clinical or functional criterion can be used as an early marker of an exacerbation. Innate and acquired immune mechanisms, modified by contact with infectious, irritant or allergenic agents, participate in the pathogenesis of exacerbations, which are accompanied by bronchial inflammation. In 2010, mortality is related to progression of exacerbations, often occurring before the patient seeks medical attention. The objective of treatment is to control asthma and prevent exacerbations. However, many factors can trigger exacerbations and often cannot be controlled. The efficacy of inhaled corticosteroids has been demonstrated on reduction of the number of exacerbations and the number of asthma-related deaths. This treatment is cost-effective, especially in terms of reduction of exacerbations.

Using genetics to predict the natural history of asthma?

Clinical practice reminds us that there is considerable variability in the course of asthma over time. Treatment of patients with asthma would be considerably improved if one could accurately predict the likely course of disease over the life course. Recently, with the advent of the era of genome-wide association studies, there has been a monumental shift in our understanding of the genetic factors that underlie inherited susceptibility to asthma. Genes have been identified that modulate many aspects of the natural history of asthma, such as susceptibility to atopy, altered lung development, and susceptibility to more severe disease. Heritability studies have even suggested a role for genetic factors in remission of asthma. However, although the discovery of novel genetic factors underlying disease susceptibility has undoubtedly improved our understanding of disease pathogenesis, whether these advances have improved the ability to predict the natural history in individual patients is questionable, and the application of genetic testing to clinical practice remains some way off.

A heritable predisposition to pituitary tumors

Pituitary tumors are prevalent in the general population, with a frequency of nearly 1 in 5. The cause of most pituitary tumors remains unknown, although a genetic contribution is recognized for some. We analyzed the Utah Population Data Base (UPDB), a resource combining a computerized genealogy of the Utah population with a statewide tumor registry, to investigate familial clustering of pituitary tumors. We analyzed the genetic relationships among 741 individuals diagnosed with benign or malignant pituitary tumors who had Utah genealogy data. To test for evidence of genetic contribution to predisposition, we compared average relatedness between all pairs of individuals with pituitary tumors with the expected relatedness in this population. We also estimated relative risks (RRs) for pituitary tumors in close and distant relatives of cases by comparing observed and expected numbers of cases among relatives. Relative risks for first- and third-degree relatives were significantly elevated (RR = 2.83 and 1.63, respectively), while relative risk for second-degree relatives was not significantly different from 1.0 (RR = 0.83). The average pairwise relatedness of pituitary tumor cases was significantly higher than expected, even when close relationships were ignored. The significantly elevated risks to relatives as well as the significant excess distant relatedness observed in cases provide strong support for a genetic contribution to predisposition to pituitary tumors. Multiple high-risk pedigrees can be identified in the UPDB, and study of such pedigrees might allow identification of the gene(s) responsible for our observations. Recognizing genetic contribution to the disease may also help with counseling family members of affected individuals.

An application of the latent p value method to assess linkage in asthma pedigrees

OBJECTIVE

The latent p value is a recently proposed empirical method for assessing evidence against a null hypothesis in a stochastic system involving latent, unobservable variables. It is particularly applicable to genome-wide genetic linkage analysis for test statistics with poorly defined analytical distributions.

METHODS

We describe an implementation of the latent p value method and its application to a linkage analysis of asthma in 81 extended pedigrees containing 1,858 people genotyped at 533 microsatellite markers. We compare the performance of the latent p value method to a more conventional p value calculation. We also compare the performance of various linkage statistics within this pedigree resource.

RESULTS

Using a novel linkage score referred to as the C-link statistic, our analysis provides strong evidence for a recessive gene influencing asthma on chromosome 5q13 (median latent p value = 0.03). We also demonstrate remarkable improvement in computational requirements compared to a more conventional empirical p value calculation.

CONCLUSIONS

The latent p value method is indeed feasible and provides a computationally efficient means to evaluate evidence for linkage regardless of the choice of linkage statistic.

Evidence for an inherited predisposition contributing to the risk for rotator cuff disease

BACKGROUND

A genetic predisposition has been suggested to contribute to the risk for development of rotator cuff disease on the basis of observed family clusters of close relatives. We used a population-based resource combining genealogical data for Utah with clinical diagnosis data from a large Utah hospital to test the hypothesis of excess familial clustering for rotator cuff disease.

METHODS

The Utah Population Database contains combined health and genealogical data on over two million Utah residents. Current Procedural Terminology, Fourth Revision, codes (29827, 23412, 23410, and 23420) and International Classification of Diseases, Ninth Revision, codes (726.1, 727.61, and 840.4) entered in patient records were used to identify patients with rotator cuff disease. We tested the hypothesis of excess familial clustering using two well-established methods (the Genealogical Index of Familiality test and the estimation of relative risks in relatives) in the overall study group (3091 patients) and a subgroup of the study group diagnosed before the age of forty years (652 patients).

RESULTS

The Genealogical Index of Familiality test in patients diagnosed before the age of forty years showed significant excess relatedness for individuals with rotator cuff disease in close and distant relationships (as distant as third cousins) (p = 0.001). The relative risk of rotator cuff disease in the relatives of patients diagnosed before the age of forty years was significantly elevated for second degree (relative risk = 3.66, p = 0.0076) and third degree (relative risk = 1.81, p = 0.0479) relatives.

CONCLUSIONS

We analyzed a set of patients with diagnosed rotator cuff disease and a known genealogy to describe the familial clustering of affected individuals. The observations of significant excess relatedness of patients and the significantly elevated risks to both close and distant relatives of patients strongly support a heritable predisposition to rotator cuff disease.

Significant evidence for linkage to chromosome 5q13 in a genome-wide scan for asthma in an extended pedigree resource

Asthma is a multifactorial disease with undetermined genetic factors. We performed a genome-wide scan to identify predisposition loci for asthma. The asthma phenotype consisted of physician-confirmed presence or absence of asthma symptoms. We analyzed 81 extended Utah pedigrees ranging from three to six generations, including 742 affected individuals, ranging from 2 to 40 per pedigree. We performed parametric multipoint linkage analyses with dominant and recessive models. Our analysis revealed genome-wide significant evidence of linkage to region 5q13 (log of the odds ratio (LOD)=3.8, recessive model), and suggestive evidence for linkage to region 6p21 (LOD=2.1, dominant model). Both the 5q13 and 6p21 regions indicated in these analyses have been previously identified as regions of interest in other genome-wide scans for asthma-related phenotypes. The evidence of linkage at the 5q13 region represents the first significant evidence for linkage on a genome-wide basis for this locus. Linked pedigrees localize the region to approximately between 92.3-105.5 Mb.

Interpatient variability in rates of asthma progression: can genetics provide an answer?

Asthma is a heterogeneous disorder with a variable natural history. In children 3 patterns of the natural history of asthma have been described: early onset but transient, persistent, and later onset, with only the former leading to persistent asthma later in childhood. In adults a range of different asthma phenotypes differing in their environmental, inflammatory, and prognostic characteristics have also been described. These extend beyond allergic (extrinsic) and nonallergic (intrinsic) asthma to include persistent airflow obstruction and accelerated decrease in lung function over time. Asthma progression can be defined as the change in an individual's phenotype along a continuum ranging from nonasthmatic to asthmatic and subsequent development of severe chronic disease. It is clear that for prevention of asthma progression in patients, there is a need for both better understanding of the pathophysiology of asthma and identification of predictors of progression. Interpatient genetic variability has been shown to affect multiple facets of asthma progression, including increased susceptibility to atopy and subsequent asthma, progression to severe disease, and modification of the response to treatment. Thus genetic testing might provide a means for predicting the likely progression of an individual along the continuum, allowing targeting of preventative treatment. However, the prospect of the use of genetic information in clinical practice raises important social and ethical issues that will need to be addressed before genetic testing can be used to inform the preventative treatment of patients to prevent the development of progression of asthma in individuals.