presence of recombinant derived RNA and DNA using a variety of molecular techniques. We have 
not included as part of the protocol an assessment of the effect of gene therapy on morbidity or 
mortality due to CAD. This would be extremely difficult in light of the heterogeneity of the 
disease and the limited number of patients to be enrolled in the study. The patients will also be 
carefully monitored for immunological responses to the recombinant derived receptor protein 
as well as morbid sequalae of cell transplantation and/or gene transfer. 
We believe that this therapy has a reasonable chance of diminishing the steady state level 
of cholesterol in the recipient which could blunt the progression of CAD. An additional benefit 
from these experiments is that we will learn more about the feasibility of ex vivo gene therapy 
which will be extremely helpful in the development of other morbid inherited metabolic 
diseases. 
B. Patient Evaluation and Selection 
Homozygous FH is an extremely morbid disease which leads to premature death due to 
sequelae of coronary artery disease (2). The natural history of homozygous FH was reviewed in 
Section II. B. 3. In brief, the level of residual LDL receptor activity is an important predictor of 
outcome: receptor negative patients (those that retain less than 2% residual receptor activity) 
die at an average age of about 11 to 12 years old (42, 43), whereas, receptor defective patients 
(those that retain greater than 2% residual receptor activity) die at an average age of 18 to 26 
years old (43-48). There is no proven effective therapy for this disease, however, most 
patients are treated with plasma exchange or LDL-apheresis, or intensive pharmacologic 
therapy (2). 
The patient population we are targeting for first attempts of gene therapy are 
homozygous FH patients whose CAD is advanced to the point where their prognosis is poor but 
they are still acceptable surgical candidates. We have elected not to subject this experimental 
therapy to patients whose prognosis is relatively good because of the relatively unknown risks 
associated with the procedure. Patients will be subjected to an extensive evaluation in order to 
assess their eligibility. A flow chart of this evaluation is provided in Figure 1. 
Patients with documented homozygous FH and symptomatic CAD will be evaluated for 
eligibility in this protocol. The diagnosis of FH will be based on the criteria of Sprecher et al. 
(43) which include a) elevated LDL cholesterol (>500 mg/dl), b) autosomal dominant mode of 
inheritance, c) early onset tendinous and tuberous xanthomas, and d) LDL receptor binding in 
cultured fibroblasts less than 20% of normal. An assessment of LDL receptor activity in 
fibroblasts will also be used to stratify this population of patients into low (receptor defective) 
and high (receptor negative) risk groups. Symptomatic CAD will be defined by the presence of 
angina pectoris or a history of myocardial infarction. 
Previous studies reviewed in Section III.B.3 indicate that receptor negative patients with 
symptomatic CAD have an extremely poor prognosis; average age of death is approximately 1 1 to 
12 years of age (42, 43). This group will, therefore, be considered candidates for gene therapy 
and will be further evaluated by the pediatric or adult cardiology service to assess the risk of 
surgery. The specific evaluation to be performed will depend on the consult services as well as 
the age and condition of the patient. A general approach to this evaluation is summarized in the 
flow chart (Figure 1) and described below. 
Initial cardiac evaluation of this group will include a history and physical exam, and an 
echocardiogram with doppler to assess left ventricular function and the possible existence of 
supravalvular or valvular aortic stenosis. Patients will be excluded from the protocol by the 
presence of any one of the following: 1) unstable angina pectoris, 2) left ventricular ejection 
fraction less than 30%, 3) decompensated congestive heart failure, 4) untreated ventricular 
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