Deficiency of Lysosomal Acid Phosphatase

Abstract

Acid phosphatase activity in a patient with a new familial metabolic disorder (characterized by intermittent vomiting, hypotonia, lethargy, opisthotonos, terminal bleeding and death in early infancy) was deficient in the lysosomal fraction of homogenates of cultivated fibroblasts, brain, liver, spleen and kidney. Amniotic-fluid cells obtained at 13 weeks in a subsequent pregnancy had no demonstrable acid phosphatase activity. The pregnancy was interrupted, and no detectable levels of acid phosphatase were found in homogenates of fetal organs. The lysosomal fraction of homogenates of cultivated fibroblasts from both parents (first cousins) had acid phosphatase levels of 3.0 ± 0.9 μmoles of p-nitrophenol phosphate (PNP) per hour per microgram of protein as compared to control levels of 7.2 ± 0.7 μmoles of PNP. Heterozygotes could not be distinguished from controls in untreated lymphocytes, whereas marked differences were found after 56 hours of phytohemagglutinin treatment. This suggests that the condition is inherited as an autosomal recessive disorder.