Friedreich's Ataxia-Health Index: Development and Validation of a Novel Disease-Specific Patient-Reported Outcome Measure.

Background and Objectives: To develop a valid, disease-specific, patient-reported outcome (PRO) measure for adolescents and adults with Friedreich ataxia (FA) for use in therapeutic trials. Methods: We conducted semistructured qualitative interviews and a national cross-sectional study of individuals with FA to determine the most prevalent and burdensome symptoms and symptomatic themes to this population. These symptoms and symptomatic themes were included as questions in the first version of the Friedreich's Ataxia-Health Index (FA-HI). We subsequently used factor analysis, beta interviews with 17 individuals with FA, and test-retest reliability assessments with 20 individuals with FA to evaluate, refine, and optimize the FA-HI. Finally, we determined the capability of the FA-HI to differentiate between subgroups of FA participants with varying levels of disease severity. Results: Participants with FA identified 18 symptomatic themes of importance to be included as subscales in the FA-HI. The FA-HI demonstrates high internal consistency and test-retest reliability, and it was identified by participants as highly relevant, comprehensive, and easy to complete. FA-HI total and subscale scores statistically differentiated between subgroups of participants with varying levels of disease burden. Discussion: Initial evaluation of the FA-HI supports its validity and reliability as a PRO for assessing how individuals with FA feel and function.

Patient-Reported Impact of Symptoms in Friedreich Ataxia.

BACKGROUND AND OBJECTIVES: To determine the prevalence and relative importance of symptoms experienced by children and adults with Friedreich ataxia (FA) and to identify factors associated with a higher burden of disease. METHODS: We conducted qualitative interviews with individuals with FA and caregivers of pediatric individuals with FA to identify potential symptoms of importance to those living with FA. We subsequently performed a cross-sectional study to assess which symptoms have the highest prevalence and importance in FA and to determine which factors are associated with a higher burden of disease. RESULTS: Thirty-nine participants provided 2,527 quotes regarding the symptomatic burden of FA. Two hundred two individuals (153 individuals with FA and 49 caregivers) participated in a subsequent cross-sectional study. Individuals with FA and caregivers identified impaired coordination, limitations with mobility and walking, inability to do activities, fatigue, and lower extremity weakness as the most prevalent and life-altering symptomatic themes in FA. Muscle stiffness and functional staging for ataxia were associated with the prevalence of symptomatic themes in FA. In addition, the length of smaller GAA expansion and the mean length of both GAA expansions were strongly associated with the onset of symptoms in FA. DISCUSSION: There are a wide variety of symptoms that affect the lives of individuals with FA. These symptoms, many underrecognized, have different levels of importance and occur at different rates in the FA population. The most common and life altering of these symptoms represent potential targets for future therapeutic interventions.

The attitude of patients with progressive ataxias towards clinical trials.

BACKGROUND: The development of new therapies may rely on the conduct of human experimentation as well as later clinical trials of therapeutic interventions. Ethical considerations seek to protect the patient from risk but few have sought to ascertain the attitude to such risk of patients with progressive debilitating or terminal conditions, for which no mitigating or curative therapies exist. Such understanding is also important if recruitment is to be maximized. We therefore sought to define the motivations for and barriers to trial participation amongst patients with progressive ataxias, as well as their condition-specific trial preferences. METHODS: We conducted an online survey consisting of 29 questions covering four key domains (demographics, personal motivation, drug therapy and study design) relating to the design of clinical trials. Two major ataxia charities, Ataxia UK and the Friedreich's Ataxia Research Alliance (FARA) sent the survey to their members. Responses were analysed by disease and by ambulatory status. RESULTS: Of 342 respondents, 204 reported a diagnosis of Friedreich's ataxia (FRDA), 55 inherited cerebellar ataxia (CA) and 70 idiopathic CA. The most important symptoms to be addressed by a trial were considered to be balance problems and ambulation, although these were superseded by speech problems in wheelchair users. Common motivations for participation were potential benefits to self and others. Reasons for non-participation included concerns about side effects, and the burden and cost of travel. Financial reimbursement for expenses was reported to be likely to increase trial engagement, Phase two trials were the most popular to participate in, and the use of a placebo arm was seen as a disincentive. Across all disease subgroups, drug repurposing trials proved popular and just under 70% of participants would be prepared to undergo intrathecal drug administration. CONCLUSIONS: Knowledge of motivations for and barriers to trial participation as well as the acceptability of investigations, time commitments and routes of drug administration should inform better, more patient focused trial design. This in turn may improve recruitment and retention of participants to future trials.

Update on molecular diagnosis of hereditary hemorrhagic telangiectasia.

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant, vascular disease hallmarked by the development of arteriovenous malformations (AVMs). Germline mutations in two genes, endoglin (ENG) and activin receptor like kinase 1 (ACVRL1), have been implicated in this disease. This report describes molecular diagnosis in a consecutive series of 600 individuals with clinical features of HHT disease. Each coding exon and flanking intronic regions of ENG and ACVRL1 genes was sequenced. Exonic copy number was quantified in probands without a coding sequence mutation. Novel nonsynonymous variants were further analyzed to predict functional consequences. In addition, common single nucleotide polymorphisms genotypes and haplotypes for the two genes were compared between individuals with and without mutations. The highest mutation detection rate (87% [95% CI 80.2-91.5]) was observed in probands who met all four Curacao criteria (epistaxis, telangiectases, AVMs and family history). More than 30% of identified mutations were novel; however, only 6% were variants of unknown significance. Determining the significance of novel mutations as related to disease presents additional challenges. Detection of multiple alterations in the same proband also requires careful evaluation for disease association. In conclusion, the sensitivity of molecular diagnosis is highest in probands with a clinically confirmed diagnosis of HHT. However, a substantial fraction of probands in this group do not carry an identifiable mutation in the coding exons of these two genes. This suggests alternate mechanisms of gene inactivation or involvement of alternate loci, and it requires further investigation.

Recent advances in retinoblastoma genetic research.

PURPOSE OF REVIEW: Retinoblastoma is a pediatric eye tumor that serves as a paradigm for understanding the genetic basis of cancer. This review will highlight recent advances in retinoblastoma genetic research and discuss how these new findings influence our knowledge of retinoblastoma tumorigenesis and management. RECENT FINDINGS: Current data demonstrate that retinomas, benign retinal tumors found in some retinoblastoma patients, exhibit bi-allelic mutations in RB1, the retinoblastoma gene, and lack of expression of the retinoblastoma protein. Interestingly, retinomas demonstrate a low level of genomic instability that becomes progressively more severe in retinoblastoma tumors. Additionally, a subset of retinomas share genomic alterations with retinoblastoma. Collectively, these data suggest that retinomas represent true premalignant lesions and not regressed retinoblastoma tumors, as previously thought. Translational advances in retinoblastoma genetic research include development of an allele-specific assay that now enables the identification of mutational mosaicism, thereby increasing the rate of RB1 mutation detection in bilaterally affected patients to as high as 95%. SUMMARY: These and related research efforts reveal novel data that enhance our understanding of the biology of retinoblastoma. These observations may facilitate new therapeutic approaches to further decrease the morbidity and mortality associated with retinoblastoma and other more common forms of cancer.

Sulfotransferase (SULT) 1A1 polymorphic variants *1, *2, and *3 are associated with altered enzymatic activity, cellular phenotype, and protein degradation.

The superfamily of sulfotransferase (SULT) enzymes catalyzes the sulfate conjugation of several pharmacologically important endo- and xenobiotics. SULT1A1 catalyzes the sulfation of small planar phenols such as neurotransmitters, steroid hormones, acetaminophen, and p-nitrophenol (PNP). Genetic polymorphisms in the human SULT1A1 gene define three alleles, SULT1A1*1, *2, and *3. The enzyme activities of the SULT1A1 allozymes were studied with a variety of substrates, including PNP, 17beta-estradiol, 2-methoxyestradiol, catecholestrogens, the antiestrogen 4-hydroxytamoxifen (OHT), and dietary flavonoids. Using purified recombinant SULT1A1 protein, marked differences in *1, *2, and *3 activity toward every substrate studied were noted. Substrate inhibition was observed for most substrates. In general, the trend in V(max) estimates was *1 > *3 > *2; however, V(max)/K(m) estimate trends varied with substrate. In MCF-7 cells stably expressing either SULT1A1*1 or *2, the antiestrogenic response to OHT was found to be allele-specific: the cells expressing *2 exhibited a better antiproliferative response. The intracellular stability of the *1 and *2 allozymes was examined in insect as well as mammalian cells. The SULT1A1*2 protein had a shorter half-life than the *1 protein. In addition, the *2 protein was ubiquitinated to a greater extent than *1, suggesting increased degradation via a proteasome pathway. The results of this study suggest marked differences in activity of polymorphic SULT1A1 variants, including SULT1A1*3, toward a variety of substrates. These differences are potentially critical for understanding interindividual variability in drug response and toxicity, as well as cancer risk and incidence.

Genetic polymorphisms in human SULT1A1 and UGT1A1 genes associate with breast tumor characteristics: a case-series study.

INTRODUCTION: Estrogens are important in breast cancer development. SULT1A1 and UGT1A1 catalyze estrogen metabolism and are polymorphic. The SULT1A1*2 protein exhibits low activity, and a TA repeat within the UGT1A1 promoter alters the level of expression of the protein. We hypothesized that the SULT1A1*2 allozyme has decreased capacity to sulfate estrogens, that the SULT1A1*2 allele conferred increased capacity of cells to proliferate in response to estrogens, and that individuals with the variant SULT1A1 and UGT1A1 genotypes exhibited different breast tumor characteristics. METHODS: The capacity for SULT1A1*2 to sulfate 17beta-estradiol and the capacity for cells expressing SULT1A1*1 or SULT1A1*2 to proliferate in response to 17beta-estradiol was evaluated. A case-series study was performed in a total of 210 women with incident breast cancer, including 177 Caucasians, 25 African-Americans and eight women of other ethnic background. The SULT1A1 and UGT1A1 genotypes were determined and a logistic regression model was used to analyze genotype-phenotype associations. RESULTS: We determined that the SULT1A1*1/*1 high-activity genotype was associated with tumor size or=60 years (odds ratio = 3.70, 95% confidence interval = 1.33-10.00, P = 0.01). Individuals with both SULT1A1 and UGT1A1 high-activity genotypes had low tumor grade (odds ratio = 2.56, 95% confidence interval = 1.04-6.25, P = 0.05). Upon stratification by estrogen receptor status, significant associations were observed predominantly in estrogen receptor-negative tumors. CONCLUSION: The data suggest that genetic variation in SULT1A1 and UGT1A1 may influence breast cancer characteristics and might be important for breast cancer prognosis.

Analysis of methotrexate and folate transport by multidrug resistance protein 4 (ABCC4): MRP4 is a component of the methotrexate efflux system.

Human MRP4 (ABCC4, MOAT-B) is a lipophilic anion transporter that is able to confer resistance to nucleotide analogues and methotrexate (MTX). We previously investigated the implications of the ability of MRP4 to confer resistance to nucleotide analogues and determined that the pump is competent in the MgATP-energized transport of cyclic nucleotides and estradiol 17beta-D-glucuronide. Here we examine the potential role of MRP4 in conferring resistance to MTX and related processes by determining the selectivity of the transporter for MTX, MTX polyglutamates, and physiological folates. In so doing, it is shown that MRP4 is active in the transport of MTX as well as the physiological folates folic acid (FA) and N(5)-formyltetrahydrofolic acid (leucovorin). MTX, FA, and leucovorin are subject to high capacity [V(max(MTX)), 0.24 +/- 0.05 nmol/mg/min; V(max (FA)), 0.68 +/- 0.14 nmol/mg/min; V(max(leucovorin)), 1.95 +/- 0.18 nmol/mg/min], low affinity [K(m(MTX)), 0.22 +/- 0.01 mM; K(m(FA)), 0.17 +/- 0.02 mM; K(m (leucovorin)), 0.64 +/- 0.23 mM] transport by MRP4. In addition, as would be expected were MRP4 a component of the MTX efflux system, its capacity to transport this agent is abrogated by the addition of a single glutamyl residue. It is also shown that glutamylation similarly affects the ability of MRP2 to transport MTX. On the basis of these transport properties, it is concluded that the efflux system for MTX includes MRP2 and MRP4, in addition to MRP1 and MRP3, and that MRP4 represents a common efflux system for both MTX and certain nucleotide analogues.