Assignment ofLIPA,associated with human acid lipase deficiency,to human chromosome 10 and comparative assignment to mouse chromosome 19

The genetics of lysosomal acid lipase (LIP) has been investigated in human-Chinese hamster and mouse-Chinese hamster somatic cell hybrids. Cellulose acetate electrophoresis of human fibroblast extracts demonstrated that LIP activity consists of three isozymes. A deficiency of LIP activity has been observed in Wolman's disease (WD), cholesterol ester storage disease (CESD), and I-cell disease (ICD); this deficiency was associated with only one LIP isozyme, LIPA. We have demonstrated concordant segregation between human LIPA and human chromosome 10 and its enzyme marker glutamate oxaloacetate transaminase-1 (GOT1) in cell hybrid clones. Previous evidence suggested the different mutations associated with WD and CESD to be in the structural gene which we assign to human chromosome 10, while a different gene, involved in the processing of LIPA, is altered in ICD. These results indicate that several types of gene products are involved in the final expression of LIPA. In mouse-Chinese hamster hybrid clones, mouseLip-1 (homologous to humanLIPA) was assigned to chromosome 19. Previously, mouseGot-1 has been assigned to chromosome 19. Thus, theLIPA-GOT1 linkage group has remained intact during the 80×10⁶ years of evolution that separates humans and mice.Preliminary report of a portion of this work has been presented (30).