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Japanese family with a deficiency of lecithin:cholesterol acyltransferase (LCAT)
Insights
This study details the ninth Japanese family diagnosed with lecithin:cholesterol acyltransferase (LCAT) deficiency, a genetic disorder affecting lipid metabolism. Key findings include severe LCAT deficiency, altered lipoprotein profiles, and renal abnormalities in affected individuals.
Area of Science:
- Biochemistry
- Genetics
- Internal Medicine
Background:
- Lecithin:cholesterol acyltransferase (LCAT) deficiency is a rare genetic disorder impacting lipid metabolism.
- This condition is characterized by low levels of high-density lipoprotein (HDL) cholesterol and impaired cholesterol esterification.
- Understanding LCAT deficiency is crucial for diagnosing and managing associated health complications.
Observation:
- The study investigates the ninth known Japanese family with LCAT deficiency.
- Affected individuals presented with corneal opacity, decreased serum HDL-cholesterol, and abnormal lipoprotein profiles (low apo A-I/A-II, high apo E).
- Renal abnormalities such as microhematuria and proteinuria were observed, alongside characteristic blood smear findings (poikilocytosis, target cells).
Findings:
- Serum LCAT activity and mass were undetectable in the proband and his brother.
- Obligate heterozygotes (proband's sons) exhibited approximately 50% of normal LCAT activity, with low-normal HDL-cholesterol and apo A-I levels.
- The findings confirm a severe LCAT deficiency within this Japanese family, consistent with previous reports.
Implications:
- This case expands the known genetic diversity of LCAT deficiency.
- Identifying affected families aids in understanding the clinical spectrum and genetic basis of LCAT deficiency.
- Further research can elucidate the precise genotype-phenotype correlations and long-term consequences of LCAT deficiency.
Abstract:
We present findings in the ninth known Japanese family with lecithin:cholesterol acyltransferase (LCAT) deficiency. A 54-year-old man (proband) and his 58-year-old brother presented with corneal opacity. Both subjects showed a marked decrease in serum high density lipoprotein (HDL)-cholesterol and in the cholesteryl ester ratio. Although apo A-I and A-II were low, apo E tended to be high. Serum LCAT activity and mass were not detectable. Urinary examination showed microhematuria or proteinuria. Renal function was normal and no anemia was demonstrated, but blood smears showed poikilocytosis with target cells. The serum LCAT activity of the proband's three sons, obligate heterozygotes of LCAT deficiency, was about one-half the normal level, and HDL-cholesterol and apo A-I levels were low normal.