Analyses of prealbumin mRNAs in individuals with familial amyloidotic polyneuropathy.

The distribution of prealbumin mRNA in various tissues of a control subject and an individual with familial amyloidotic polyneuropathy (FAP) was investigated using a cloned human prealbumin cDNA as a probe. Prealbumin mRNAs were detected in the total RNAs from liver and choroid plexus of brain, but not in those from brain, heart, kidney, and thyroid gland. The level of prealbumin mRNA in the choroid plexus was about 100-fold higher than that in the liver. We detected no differences in the sizes of prealbumin mRNAs in the liver and choroid plexus of the control subject, or in those of the individual with FAP, and found that the prealbumin mRNAs in these tissues had been transcribed from a common transcription initiation site. The levels of prealbumin mRNAs in the livers of four control subjects and those of six individuals with FAP were much the same. Because all the individuals with FAP so far examined were heterozygous for the prealbumin gene, carrying one normal and one mutant gene, the levels of the normal and mutant prealbumin mRNAs in the liver and the brain tissue containing choroid plexus were separately estimated and were found to be approximately equal.