Type C Niemann-Pick disease: documentation of abnormal LDL processing in lymphocytes

Area of Science:

• Biochemistry
• Genetics
• Cell Biology

Background:

• Niemann-Pick disease (Type C) is an inherited neurovisceral disorder.
• It involves abnormal intracellular cholesterol processing.
• This defect is present in fibroblasts of patients and carriers.

Purpose of the Study:

• To examine LDL-cholesterol esterification in cultured lymphocytes from NPC patients, heterozygotes, and controls.
• To correlate biochemical findings with cellular cholesterol accumulation.
• To assess lymphocyte-based diagnosis for NPC.

Main Methods:

• Cultured lymphocytes from 8 NPC patients, 8 heterozygotes, and 8 controls.
• Measurement of cholesteryl ester synthesis.
• Histochemical and electron microscopic examination of lymphocytes.

Main Results:

• Cholesteryl ester synthesis was significantly reduced in homozygous (8%) and heterozygous (45%) NPC cell lines compared to controls.
• Abnormal intracellular accumulation of unesterified cholesterol was observed in mutant lymphocytes.
• Lymphocyte cholesterol esterification accurately reflects the biochemical defect in NPC.

Conclusions:

• Lymphocyte cholesterol esterification is a reliable diagnostic marker for Niemann-Pick disease (Type C).
• Cultured lymphocytes are a valuable tool for studying the molecular basis of NPC.
• This method offers a quick and reliable confirmation of NPC diagnosis.