The need for continuous quality assessment for providing optimal comprehensive care for patients with alpha-1 antitrypsin deficiency.

Background: Alpha-1-antitrypsin deficiency (AATD) is an orphan disease that mainly affecting the liver and the lung. This creates difficulties to ensure that comprehensive care is administered to both organ systems. Past assessments of care delivered to patients with AATD demonstrated that improvements are needed. For that reason, we reassessed a population of patients with AATD in a large health care system to see if past findings affected present care. Methods: We performed electronic health record (EHR) reviews on all patients with documented AATD and confirmed the diagnosis by evidence of genotyping. We then selected the patients with the ZZ genotype to review comprehensive care. We further compared the findings in patients treated by different specialists (allergy immunology, gastroenterology, and pulmonary). The data were captured and assessed by using a secure web application for building and managing online surveys and data bases. REDCap. Results: We found a total of 329 patients with diagnostic codes for AATD, of these, 203 patients had a confirmed abnormal genotype. Confirmed genotypes were MZ (n = 69), ZZ (n = 48), MS (n = 22), SZ (n = 22). Further focus was applied to the care of the ZZ population secondary to a predisposition to potential severe lung and liver disease. The findings suggest that care can be improved no matter which specialist cares for the patient. Conclusion: Our study demonstrated that all three subspecialty groups had room for improvement in providing care to patients with AATD. Our study further demonstrated the need for recurrent quality-assurance programs that may be aided by care suggestions built into the EHR.

[Screening for alpha1-antitrypsin deficiency using dried blood spot: Assessment of the first 20 months]. / Dépistage du déficit en alpha1-antitrypsine sur sang capillaire recueilli sur papier-filtre : bilan des 20 premiers mois.

INTRODUCTION: Alpha1-antitrypsin deficiency is a predisposing factor for pulmonary disease and under-diagnosis is a significant problem. The results of a targeted screening in patients with respiratory symptoms possibly indicative of severe deficiency are reported here. METHODS: Data were collected from March 2016 to October 2017 on patients who had a capillary blood sample collected during a consultation with a pulmonologist and sent to the laboratory for processing to determine alpha1-antitrypsin concentration, phenotype and possibly genotype. RESULTS: In 20 months, 3728 test kits were requested by 566 pulmonologists and 718 (19 %) specimens sent: among these, 708 were analyzable and 613 were accompanied by clinical information. Of the 708 samples, 70 % had no phenotype associated with quantitative alpha1- antitrypsin deficiency, 7 % had a phenotype associated with a severe deficiency and 23 % had a phenotype associated with an intermediate deficiency. One hundred and eight patients carried at least one PI*Z allele which is considered to be a risk factor for liver disease. CONCLUSIONS: The results of this targeted screening program for alpha1- antitrypsin deficiency using a dried capillary blood sample reflect improvement in early diagnosis of this deficiency in lung disease with good adherence of the pulmonologists to this awareness campaign.

The undiagnosed disease burden associated with alpha-1 antitrypsin deficiency genotypes.

Alpha-1 antitrypsin deficiency (AATD), mainly due to the PI*ZZ genotype in SERPINA1, is one of the most common inherited diseases. Since it is associated with a high disease burden and partially prevented by smoking cessation, identification of PI*ZZ individuals through genotyping could improve health outcomes.We examined the frequency of the PI*ZZ genotype in individuals with and without diagnosed AATD from UK Biobank, and assessed the associations of the genotypes with clinical outcomes and mortality. A phenome-wide association study (PheWAS) was conducted to reveal disease associations with genotypes. A polygenic risk score (PRS) for forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio was used to evaluate variable penetrance of PI*ZZ.Among 458 164 European-ancestry participants in UK Biobank, 140 had the PI*ZZ genotype and only nine (6.4%, 95% CI 3.4-11.7%) of them were diagnosed with AATD. Those with PI*ZZ had a substantially higher odds of COPD (OR 8.8, 95% CI 5.8-13.3), asthma (OR 2.0, 95% CI 1.4-3.0), bronchiectasis (OR 7.3, 95%CI 3.2-16.8), pneumonia (OR 2.7, 95% CI 1.5-4.9) and cirrhosis (OR 7.8, 95% CI 2.5-24.6) diagnoses and a higher hazard of mortality (2.4, 95% CI 1.2-4.6), compared to PI*MM (wildtype) (n=398 424). These associations were stronger among smokers. PheWAS demonstrated associations with increased odds of empyema, pneumothorax, cachexia, polycythaemia, aneurysm and pancreatitis. Polygenic risk score and PI*ZZ were independently associated with FEV1/FVC <0.7 (OR 1.4 per 1-sd change, 95% CI 1.4-1.5 and OR 4.5, 95% CI 3.0-6.9, respectively).The important underdiagnosis of AATD, whose outcomes are partially preventable through smoking cession, could be improved through genotype-guided diagnosis.

Reduced Susceptibility to VIRIP-Based HIV-1 Entry Inhibitors Has a High Genetic Barrier and Severe Fitness Costs.

VIRIP has been identified as natural HIV-1 inhibitor targeting the gp41 fusion peptide. An optimized analogue (VIR-576) was effective in a phase I/II clinical trial and initial studies showed that HIV-1 resistance to VIRIP-based inhibitors has a high genetic barrier. Partially resistant CXCR4 (X4)-tropic HIV-1 NL4-3 variants could be obtained, however, after more than 15 months of passaging in MT-4 cells in the presence of another derivative (VIR-353). Sequence analyses identified the accumulation of seven mutations across the HIV-1 envelope glycoprotein but outside the gp41 fusion peptide. The authors suggested that the three initial alterations conferred resistance, while subsequent changes restored viral fitness. Here, we introduced these mutations individually and in combination into X4- and CCR5 (R5)-tropic HIV-1 constructs and determined their impact on VIR-353 and VIR-576 susceptibility, viral infectivity, replication fitness, and fusogenicity. We found that essentially all seven mutations contribute to reduced susceptibility to VIRIP-based inhibitors. HIV-1 constructs containing ≥4 changes were substantially more resistant to both VIRIP-based inhibitors and the VRC34.01 antibody targeting the fusion peptide. However, they were also much less infectious and fusogenic than those harboring only the three initial alterations. Furthermore, the additional changes attenuated rather than rescued HIV-1 replication in primary human cells. Thus, the genetic barrier to HIV-1 resistance against VIRIP-based inhibitors is higher than previously suggested, and mutations reducing viral susceptibility come at a severe fitness cost that was not rescued during long-term cell culture passage.IMPORTANCE Many viral pathogens are critically dependent on fusion peptides (FPs) that are inserted into the cellular membrane for infection. Initially, it was thought that FPs cannot be targeted for therapy because they are hardly accessible. However, an optimized derivative (VIR-576) of an endogenous fragment of α1-antitrypsin, named VIRIP, targeting the gp41 FP reduced viral loads in HIV-1-infected individuals. Characterization of HIV-1 variants selected during long-term cell-culture passage in the presence of a VIRIP derivative suggested that just three mutations in the HIV-1 Env protein might be sufficient for VIRIP resistance and that four subsequent changes restored viral fitness. Here, we show that all seven mutations contribute to reduced viral susceptibility to VIRIP-based inhibitors and demonstrate that the additional changes strongly impair rather than rescue HIV-1 infectivity, fusogenicity, and replication fitness. High genetic barrier to resistance and severe fitness cost support further clinical development of this class of antiviral agents.

Comparison of non-invasive assessment of liver fibrosis in patients with alpha1-antitrypsin deficiency using magnetic resonance elastography (MRE), acoustic radiation force impulse (ARFI) Quantification, and 2D-shear wave elastography (2D-SWE).

PURPOSE: Although it has been known for decades that patients with alpha1-antitrypsin deficiency (AATD) have an increased risk of cirrhosis and hepatocellular carcinoma, limited data exist on non-invasive imaging-based methods for assessing liver fibrosis such as magnetic resonance elastography (MRE) and acoustic radiation force impulse (ARFI) quantification, and no data exist on 2D-shear wave elastography (2D-SWE). Therefore, the purpose of this study is to evaluate and compare the applicability of different elastography methods for the assessment of AATD-related liver fibrosis. METHODS: Fifteen clinically asymptomatic AATD patients (11 homozygous PiZZ, 4 heterozygous PiMZ) and 16 matched healthy volunteers were examined using MRE and ARFI quantification. Additionally, patients were examined with 2D-SWE. RESULTS: A high correlation is evident for the shear wave speed (SWS) determined with different elastography methods in AATD patients: 2D-SWE/MRE, ARFI quantification/2D-SWE, and ARFI quantification/MRE (R = 0.8587, 0.7425, and 0.6914, respectively; P≤0.0089). Four AATD patients with pathologically increased SWS were consistently identified with all three methods-MRE, ARFI quantification, and 2D-SWE. CONCLUSION: The high correlation and consistent identification of patients with pathologically increased SWS using MRE, ARFI quantification, and 2D-SWE suggest that elastography has the potential to become a suitable imaging tool for the assessment of AATD-related liver fibrosis. These promising results provide motivation for further investigation of non-invasive assessment of AATD-related liver fibrosis using elastography.

State-of-the-art testing for alpha-1 antitrypsin deficiency.

BACKGROUND: Alpha-1 antitrypsin deficiency (AATD) is a genetic condition characterized by low serum levels of the protein alpha-1 antitrypsin. Because there are no unique clinical symptoms that point to a definitive diagnosis of AATD, laboratory testing is crucial to differentiate this disease from others. OBJECTIVE: To summarize advances in laboratory techniques used to test for AATD. METHODS: Data were sourced from a nonsystematic literature review of MEDLINE and the author's personal literature collection, and by checking reference lists of sourced articles. RESULTS: Since the original description of AATD by Laurell and Eriksson in 1963, testing methods have undergone major changes. Currently, alpha-1 antitrypsin protein is quantified by immunologic measurement in serum, and the phenotype is characterized by isoelectric focusing and/or targeted genotyping of predefined mutations. In addition, whole-gene sequencing of the gene SERPINA1 can be undertaken. However, this is costly and generally used only if targeted genotyping cannot conclusively identify the variant. The introduction of next-generation sequencing (NGS), which enables rapid and accurate sequencing of large quantities of DNA fragments in a single reaction, may help reduce costs. With its increasing availability, NGS may begin to appear in testing protocols. Clinical guidelines recommend that patients are tested for AATD if they have chronic irreversible airflow obstruction, especially those with early onset disease or a positive family history of AATD. Despite this, AATD is still underrecognized, and significant delays exist between symptom onset and diagnosis. CONCLUSION: Traditional testing practices have limitations. Screening programs that incorporate NGS are the most comprehensive methods available for accurate diagnosis of AATD.

α-1-Antitrypsin deficiency: clinical variability, assessment, and treatment.

The recognition of α-1-antitrypsin deficiency, its function, and its role in predisposition to the development of severe emphysema was a watershed in our understanding of the pathophysiology of the condition. This led to the concept and development of intravenous replacement therapy used worldwide to protect against lung damage induced by neutrophil elastase. Nevertheless, much remained unknown about the deficiency and its impact, although in recent years the genetic and clinical variations in manifestation have provided new insights into assessing impact, efficacy of therapy, and development of new therapeutic strategies, including gene therapy, and outcome measures, such as biomarkers and computed tomography. The current article reviews this progress over the preceding 50 years.

Imbalance between neutrophil elastase and its inhibitor α1-antitrypsin in obesity alters insulin sensitivity, inflammation, and energy expenditure.

The molecular mechanisms involved in the development of obesity and related complications remain unclear. Here, we report that obese mice and human subjects have increased activity of neutrophil elastase (NE) and decreased serum levels of the NE inhibitor α1-antitrypsin (A1AT, SerpinA1). NE null (Ela2(-/-)) mice and A1AT transgenic mice were resistant to high-fat diet (HFD)-induced body weight gain, insulin resistance, inflammation, and fatty liver. NE inhibitor GW311616A reversed insulin resistance and body weight gain in HFD-fed mice. Ela2(-/-) mice also augmented circulating high molecular weight (HMW) adiponectin levels, phosphorylation of AMP-activated protein kinase (AMPK), and fatty acid oxidation (FAO) in the liver and brown adipose tissue (BAT) and uncoupling protein (UCP1) levels in the BAT. These data suggest that the A1AT-NE system regulates AMPK signaling, FAO, and energy expenditure. The imbalance between A1AT and NE contributes to the development of obesity and related inflammation, insulin resistance, and liver steatosis.

In silico assessment of potential druggable pockets on the surface of α1-antitrypsin conformers.

The search for druggable pockets on the surface of a protein is often performed on a single conformer, treated as a rigid body. Transient druggable pockets may be missed in this approach. Here, we describe a methodology for systematic in silico analysis of surface clefts across multiple conformers of the metastable protein α(1)-antitrypsin (A1AT). Pathological mutations disturb the conformational landscape of A1AT, triggering polymerisation that leads to emphysema and hepatic cirrhosis. Computational screens for small molecule inhibitors of polymerisation have generally focused on one major druggable site visible in all crystal structures of native A1AT. In an alternative approach, we scan all surface clefts observed in crystal structures of A1AT and in 100 computationally produced conformers, mimicking the native solution ensemble. We assess the persistence, variability and druggability of these pockets. Finally, we employ molecular docking using publicly available libraries of small molecules to explore scaffold preferences for each site. Our approach identifies a number of novel target sites for drug design. In particular one transient site shows favourable characteristics for druggability due to high enclosure and hydrophobicity. Hits against this and other druggable sites achieve docking scores corresponding to a K(d) in the µM-nM range, comparing favourably with a recently identified promising lead. Preliminary ThermoFluor studies support the docking predictions. In conclusion, our strategy shows considerable promise compared with the conventional single pocket/single conformer approach to in silico screening. Our best-scoring ligands warrant further experimental investigation.

A review of augmentation therapy for alpha-1 antitrypsin deficiency.

INTRODUCTION: Alpha-1 antitrypsin deficiency (AATD) is a relatively common, but under-recognized condition which manifests commonly with liver cirrhosis and emphysema. Specific therapy for lung-affected individuals with AATD is augmentation therapy, which consists of intravenous infusion of purified human plasma-derived alpha-1 antitrypsin (AAT). Augmentation therapy was first approved by the United States Food and Drug Administration (FDA) in 1987 for emphysema associated with severe AATD and today, six augmentation therapy preparations, all of which derive from pooled human plasma, have received FDA approval. AREAS COVERED: This paper reviews augmentation therapy for AATD, including the various available commercial preparations, their processing and biochemical differences, evidence regarding biochemical and clinical efficacy, patterns of clinical use, adverse effect profiles, cost-effectiveness and potential uses in conditions other than emphysema associated with AATD. Novel and emerging strategies for treating AATD are briefly discussed next, including alternative dosing and administration strategies, recombinant preparations, small molecule inhibitors of neutrophil elastase and of AAT polymerization, autophagy-enhancing drugs and gene therapy approaches. EXPERT OPINION: We conclude with a discussion of our approach to managing patients with AATD and use of augmentation therapy.

Computational methods for studying serpin conformational change and structural plasticity.

Currently, over a hundred high-resolution structures of serpins are available, exhibiting a wide range of conformations. However, our understanding of serpin dynamics and conformational change is still limited, mainly due to challenges of monitoring structural changes and characterizing transient conformations using experimental methods. Insight can be provided, however, by employing theoretical and computational approaches. In this chapter, we present an overview of such methods, focusing on molecular dynamics and simulation. As serpin conformational dynamics span a wide range of timescales, we discuss the relative merits of each method and suggest which method is suited to specific conformational phenomena.

Emerging drugs for alpha-1-antitrypsin deficiency.

IMPORTANCE OF THE FIELD: Alpha-1-antitrypsin (A1AT) deficiency is a common genetic condition that predisposes individuals to the development of chronic obstructive pulmonary disease (COPD) as a direct result of damage caused to the lung by proteolytic enzymes released by migrating neutrophils. The lack of A1AT fails to control these enzymes and in the most common genetic deficiency (Pi Z) is due to accumulation of A1AT in the liver as a result of polymer formation. There is no specific treatment for COPD but understanding the pathophysiology of the disease in A1AT deficiency has led to strategies being used or developed to prevent the lung and liver disease. These strategies may have benefits beyond A1AT deficiency. AREAS COVERED IN THIS REVIEW: The review covers the history of discovery of the nature and role of A1AT deficiency with particular emphasis on the pathophysiology of the lung disease. Evidence for the role of current therapies is provided together with data of preliminary or experimental strategies that are under development. WHAT THE READER WILL GAIN: The reader will gain insight into the role of proteinases in the pathophysiology of COPD with particular reference to A1AT deficiency, which is the only human model of the disease. Current evidence of the efficacy of augmentation is provided together with new ways of readdressing the balance between neutrophil proteinases and natural or synthetic inhibitors or repairing lung damage. TAKE HOME MESSAGE: A1AT deficiency is a good model to investigate the role of inflammation and proteolytic enzymes in the pathophysiology of COPD. Augmentation therapy is expensive but restores the deficiency to normal and current evidence suggests this ameliorates progression of the disease. Understanding the mechanisms involved has led to the development of newer strategies to protect the lung and liver from the development of disease but efficacy and safety concerns require careful introduction of these strategies. Although the condition is relatively common in the Northern hemisphere, the ability to deliver conventional Phase III clinical trials with lung physiology as the primary outcome will be limited by the sensitivity of the tests and number of patients required.

Comparison of the properties of rare variants of alpha1-proteinase inhibitor expressed in COS-1 cells and assessment of their potential as risk factors in human disease.

Among the more than 75 known variants of alpha(1)-proteinase inhibitor, a sub-population of rare, point mutations causing single amino acid replacements have been identified and classified as "at risk" alleles for development of pulmonary disease. In most cases, it is not clear how the amino acid replacements typical of these variants change the properties of the inhibitor to increase risk of disease in the affected individuals. To begin to address this question, we mutagenized a wild type alpha(1)-proteinase inhibitor cDNA to encode a panel of eight different point mutants reported to be associated with increased risk for development of pulmonary disease. These variants were then expressed in COS-l cells transiently transfected with plasmids containing the altered cDNAs. The effects of the mutations on the rates of secretion, cellular location, intracellular degradation, activity, stability, and tendency to aggregate were determined. Results of these studies show that, in some cases, the mutations affect the rate of secretion, the activity or both of these properties of alpha(1)-proteinase inhibitor in a manner consistent with its designation as an "at-risk" allele. In other cases, the mutations do not significantly change the properties of the inhibitor, suggesting that these may be normal variants and that their expression may not increase the risk of disease.

Augmentation therapy for alpha(1)-antitrypsin deficiency.

alpha(1)-Antitrypsin (AAT) deficiency is a common but under-recognised condition. Since its first description by Laurell and Eriksson in 1963, significant advances have been made in understanding the genetics, physiology and pathophysiology of this condition. The intravenous administration of purified AAT to AAT-deficient individuals has been shown to confer biochemical efficacy by raising the serum AAT level above an epidemiologically established 'protective threshold' while preserving the biochemical properties and functional capacity of the protease inhibitor. Although the lack of a large randomised controlled trial to date has precluded the definitive demonstration of clinical efficacy of intravenous AAT augmentation therapy, substantial evidence supporting its use in AAT-deficient individuals with moderate airflow obstruction has accumulated. For example, both large observational studies comparing rates of forced expiratory volume decline among recipients of augmentation therapy versus non-recipients have shown slower rates of decline among augmentation therapy recipients, especially those with moderately severe airflow obstruction. Also, some evidence suggests that use of augmentation therapy confers an anti-inflammatory effect. For example, a web-based survey suggested that recipients of augmentation therapy experienced fewer respiratory infections than non-recipients. Despite its high cost, intravenous AAT augmentation therapy remains the only US FDA-approved treatment option for patients with AAT deficiency. Research into new and evolving treatments is currently underway.

Genetic diversity of serum proteins in three subpopulations of the Maria Gond tribe of Madhya Pradesh, India.

The phenotype and allele frequency distribution of group specific component (GC), transferrin (TF), alpha-1-antitrypsin (PI) and apolipoprotein E (APOE) was determined by isoelectric focusing of plasma samples from three subpopulations (Bison Horn Maria of the Kuakonda and Tokapal Block, and Abuj Maria of the Abujmar Hills of the Orchha block) of the Maria Gond tribe of Madhya Pradesh, India. A considerable level of allele frequency variation was observed in these subpopulations, which highlighted social and geographical isolation among them. The average heterozygosity for these IEF subtype systems was high (29-39%) and the gene diversity among these subpopulation groups was of low to moderate range (1.4%). The overall analysis showed that these polymorphisms are useful anthropological markers for micro-evolutionary and genetic structure studies.

A preliminary assessment of alpha-1 antitrypsin S and Z deficiency allele frequencies in common variable immunodeficiency patients with and without bronchiectasis.

Common variable immunodeficiency (CVID) is the name given to a clinically heterogeneous group of hypogammaglobulinaemic immunodeficiency states. Bronchiectasis is a feature of this disease and is believed to be the result of recurrent bacterial infection affecting the respiratory tract. Bronchiectasis is also a feature associated with emphysematous changes of the lung in alpha-1 antitrypsin (AAT) deficiency, a serious and relatively common disease, affecting 1 : 2000 in the United Kingdom. This has been demonstrated to result from possession of deficiency alleles, the most clinically important alleles being PI*Z and PI*S. Isolated reports of families with antibody deficiency and AAT deficiency have been published but to date no study has been performed to specifically investigate if AAT deficiency is associated with the lung damage seen in CVID patients. We have developed a PCR genotyping assay that identifies S and Z deficiency alleles and we have used this assay in a preliminary study to investigate the occurrence of these deficiency alleles of AAT in 43 CVID patients. Results of this preliminary study suggest that CVID patients did not have an altered distribution of AAT genes when compared to 70 normal controls. Subgrouping of CVID patients into those with and without bronchiectasis demonstrated a Z allele frequency of 0.077 in those patients with bronchiectasis, which is higher than found in normal controls, namely 0.029 (P < 0.15). Due to the relatively small numbers studied, these results are inconclusive in determining whether AAT deficiency may exacerbate lung damage in some CVID patient, the data does however, indicate that a larger multi-centre study involving many more CVID patients may be useful.

Assessment of bystander effect potency produced by intratumoral implantation of HSVtk-expressing cells using surrogate marker secretion to monitor tumor growth kinetics.

A molecular marker, human alpha-1-antitrypsin (hAAT) was transduced into tumor cells and its secretion was found to correlate with tumor growth or regression, allowing for an accurate and continuous measurement of tumor growth kinetics. Using this system, we investigated the therapeutic potential produced purely from the bystander effect of HSVtk+ CT26 cells to eradicate established CT26 colon carcinomas in mice by direct intratumoral implantation and subsequent ganciclovir administration. With lower ratios (0.1% and 1% of initial tumor burden), tumor growth kinetics went into a static (remission) phase of approximately 2 weeks duration before relapse and resumption of progressive tumor growth. When the number of CT26tk+ modified cells injected into the tumor equaled 10% to 100% of the initial tumor cell number the bystander effect was sufficient to completely eradicate established tumors indicating that a potent bystander killing effect is produced in this system, and that a cellular therapy based on this approach may have applications.

Genetic variation of serum proteins (GC, TF and PI subtypes) in the Baigas of Madhya Pradesh, India.

The distribution of group specific component (GC), transferrin (TF) and alpha-1-antitrypsin (PI) subtypes was determined by isoelectric focusing of plasma samples from 140 unrelated individuals belonging to the Baiga tribe of Madhya Pradesh, India. The allele frequencies observed for GC (GC*1S = 0.6742, GC*1F = 0.1326 and GC*2 = 0.1932), TF (TF*C1 = 0.7920, TF*C2 = 0.1606, TF*C3 = 0.0146 and TF*D = 0.0328) and PI (PI*M1 = 0.7179, PI*M2 = 0.1750, PI*M3 = 0.0893, PI*S = 0.0107 and PI*F = 0.0071) demonstrate appreciable heterogeneity of the Baigas compared to other populations of the region.

Alpha 1-antitrypsin deficiency. Impact of genetic discovery on medicine and society.

An increasing body of molecular information resulting from advances in basic research is being incorporated into clinical practice by medical genetics. The process by which these research advances progress from the laboratory to the bedside and their medical, social, and legal impact is a topic of intense current interest. Some authors have claimed that new genetic information may lead to discrimination in insurance and employment; change the way courts allocate responsibility for injury and resultant damages; and be inappropriately interpreted by the medical profession. To address some of these issues, we chose, as a model, to review alpha 1-antitrypsin deficiency, described over 30 years ago. At this time, such concerns with respect to alpha 1-antitrypsin deficiency have not yet been realized, perhaps for the following reasons: (1) knowledge of alpha 1-antitrypsin deficiency, while common among geneticists and pulmonologists, has not been well disseminated in the medical community; (2) insurers, employers, lawyers, and judges are not generally aware of the deficiency and its implications; (3) insurers, if they are aware of the deficiency, have not found it cost-effective to screen for the condition; and (4) in the legal context, case law involving other types of preexisting conditions is being applied to genetic predispositions.