Alj Edwin Milgrom

binding site of the AFP gene promoter in one (2 ). AFP is a widely used tumor marker. Although HPAFP is a rare disorder, it needs to be considered and differentiated from tumors to avoid inappropriate explorations and treatment decisions. We present a simple test based on restriction fragment length polymorphism (RFLP) analysis for screening of HPAFP mutations. This test can be used in patients with increased AFP not accompanied by any obvious tumor or liver disease, and may avoid invasive studies. We have previously reported two unrelated families with HPAFP related to 119G A and 55C A substitutions (2 ). The 119G A mutation creates a PshAI restriction site. A gain of this site in HPAFP patients with the 119G A mutation produced two fragments on agarose gel electrophoresis compared with the one obtained from an individual without the substitution (Fig. 1A). DNA isolated from four individuals of family 1 was tested for the presence of the 119G A mutation by RFLP analysis. All of these patients also had increased AFP and were heterozygous for the RFLP (Fig. 1B). The individual with a normal AFP concentration was homozygous for the wild-type (WT) allele. The 55C A mutation abolished a SpeI restriction site. A loss of this site in HPAFP patients with the 55C A mutation produced one fragment on agarose gel electrophoresis compared with the two fragments obtained from a control individual (Fig. 1C). DNA isolated from seven individuals of family 2 was tested for the presence of the 55C A mutation by RFLP analysis. All of the affected family members who had increased serum AFP were heterozygous for the RFLP (Fig. 1D). The five individuals with normal AFP concentrations were homozygous for the WT allele. Our RFLP analysis is potentially useful for direct detection of both mutations known to be associated with HPAFP (2–4). Detection of the 119G A substitution by conformation-sensitive gel electrophoresis has recently been proposed (5 ). However, this method was designed for detection of the 119G A substitution and not of the second reported mutation ( 55C A). Our RFLP test is inexpensive and simple to perform.