From Xanthomas to Genetic Diagnosis: A Case Report of Sitosterolemia in an Infant
with a Homozygous ABCG5 c 1166G A (p Arg389His) Variant
#MMPMID41340881
Deng Y
; Wang H
; Tang D
; Peng CE
Clin Cosmet Investig Dermatol
2025[]; 18
(?): 3189-3194
PMID41340881
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INTRODUCTION: Sitosterolemia is a rare autosomal recessive disorder characterized
by disrupted lipid metabolism and elevated plasma plant sterol levels. Clinical
manifestations often include cutaneous and tendon xanthomas and
hypercholesterolemia; delayed diagnosis can lead to cardiovascular disease and
hematological abnormalities. This case report describes an 11-month-old female
infant with sitosterolemia who presented with xanthomas appearing around 6 months
of age. Genetic sequencing identified a homozygous ABCG5 c.1166G>A (p.Arg389His)
mutation. This report aims to discuss the clinical features and genetic diagnosis
of sitosterolemia caused by ABCG5 mutations, highlighting the challenges and key
characteristics for early diagnosis to improve clinical awareness. CASE AND
METHODS: Clinical data of a pediatric patient with sitosterolemia caused by a
homozygous ABCG5 gene mutation were retrospectively analyzed. RESULTS: An
11-month-old female infant developed linear xanthomas in the skin folds of her
ankles at approximately 6 months of age, which progressively worsened. Blood
tests revealed significantly elevated total cholesterol and low-density
lipoprotein cholesterol (LDL-C) levels. Sequencing of coding regions for genes
associated with familial hypercholesterolemia and sitosterolemia identified a
homozygous ABCG5 mutation: c.1166G>A (p.Arg389His). Sanger sequencing confirmed
that this variant was inherited from each parent in a heterozygous state. The
diagnosis of sitosterolemia was confirmed based on genetic testing (ABCG5/ABCG8),
lipid profile results, and clinical presentation. CONCLUSION: Sitosterolemia
should be suspected in patients presenting with cutaneous xanthomas, prompting
thorough investigation including lipid profiling, genetic testing, and plasma
plant sterol quantification to avoid misdiagnosis as familial
hypercholesterolemia (FH).
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