The Clinical, Biochemical, and Familial Presentation of Type V Hyperlipoproteinemia in Childhood.

Abstract. Primary type V hyperlipoproteinemia was identified in two preadolescent children. The propositus (kindred N) was a 10-year-old girl with severely creamy plasma, lipemia retinalis, hypertriglyceridemia (triglyceride level. 6,800 mg/100 ml), and hypercholesterolemia (cholesterol level, 490 mg/100 ml). Her parents and an 8-year-old sister all had endogenous hypertriglyceridemia (type IV hyperlipoproteinemia). In kindred A, an 11-year-old boy had triglyceride levels as high as 1,100 mg/100 ml and recurrent abdominal pain. His father had type V hyperlipoproteinemia; his mother was normal. All three of his older teenage siblings had type IV hyperlipoproteinemia. The enzymatic activities of lipoprotein lipase (LPL), hepatic triglyceride lipase (HTL), and histaminase (H) were studied in postheparin plasma. The LPL level was low in the children and both parents in kindred N. LPL level in kindred A was normal, except for one child with type IV hyperlipoproteinemia. HTL level was normal to above normal in both kindreds. Most patients had a normal H level, but one parent (kindred N) had no preheparin H and very low levels of postheparin H. There was a strong correlation (r = 0.58, significant at < 1% level) between the release of LPL and H but not between HTL and H (r = 0,22). The mean (+/- 1 S.D.) levels of the enzymes were as follows: LPL, 2.8 +/- 0.7 micro mol/ml/hr in kindred N and 5.4 +/- 2.2 micro mol/ml/hr in kindred A; H, 13.4 +/- 6.8 units/ml in kindred N and 22.0 +/- 11.9 units/ml in kindred A; and HTL, 18.0 +/- 7.1 micro mol/ml/hr in kindred N and 14.9 +/- 6.3 micro mol/ml/hr in kindred A. The enzymatic activities of kindreds N and A were significantly different for LPI, (P < .001) and H (.025 < P < .05) but not... [ABSTRACT FROM AUTHOR]