Abstract
Lysosomal Acid Phosphatase Deficiency (LAPD) is characterized by vomiting, lethargy, opisthotonus, terminal bleeding and death in early infancy (Nadler & Egan, NEJM: 282: 302, 1970). Acid phosphatase (AcP) activity in fibroblast from patients with this disorder is decreased to 30% of normal in original homogenates (OH) and to less than 2% in the lysosomal fraction (Lys). Recently we have observed a patient with similar clinical manifestations but who expired at 36 hours of age. AcP in his fibroblasts was reduced to 2% of normal in OH and was not detectable in Lys. Therefore, this was considered to represent a total acid phosphatase deficiency (TAPD).
In comparing the AcP activities of the two patients with normal, several differences were notes. Addition of 1 ug/ml of prednisolone to these cultures induced AcP to 50% of normal in LAPD cells but had no effect on TAPD cells. This induction was inhibited by actinomycin D, puromycin and chloramphenicol. After mixing and hybridization of LAPD and TAPD cells an increase in AcP activity up to 50% of normal could be observed in OH and Lys after one week. Addition of prednisolone could not induce any further AcP activity in the mixed or hybrid cultures.
These studies clearly indicate genetic heterogeneity for acid phosphatase deficiency. The stimulation of AcP activity by prednisolone suggests that the basic defect in LAPD is an altered regulatory mechanism in contrast to that of a structural gene defect in TAPD. The potential usefulness of prednisolone theraphy in patients with LAPD is suggested.
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Nadler, H. Genetic heterogeneity in acid phosphatase deficiency. Pediatr Res 5, 421 (1971). https://doi.org/10.1203/00006450-197108000-00209
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DOI: https://doi.org/10.1203/00006450-197108000-00209