Familial hypercholesterolemia in Utah kindred with novel R103W mutations in exon 4 of the LDL receptor gene

Area of Science:

• Genetics
• Cardiovascular Medicine
• Molecular Biology

Background:

• Familial hypercholesterolemia (FH) causes significantly elevated LDL cholesterol from childhood, leading to early coronary artery disease.
• Existing diagnostic criteria for FH are inadequate, causing under-diagnosis in families and over-diagnosis in the general population.
• Accurate, genetically validated criteria are crucial for early heterozygous FH diagnosis.

Purpose of the Study:

• To identify and validate genetic criteria for diagnosing heterozygous familial hypercholesterolemia (FH).
• To investigate a specific family with suspected FH and elevated LDL cholesterol levels.

Main Methods:

• Screening of all 18 exons and exon-intron boundaries of the LDL receptor gene for mutations.
• Utilizing Single-Strand Conformation Polymorphism (SSCP) method for mutation analysis in family members.
• Molecular genetic diagnosis to confirm FH status.

Main Results:

• A novel point mutation (C-to-T transversion at nucleotide 369) in the LDL receptor gene was identified in the proband.
• This mutation results in an amino acid substitution (Tryptophan to Arginine at codon 103 in exon 4).
• SSCP analysis confirmed the proband as heterozygous for the mutation, while six relatives were excluded from FH carrier status.

Conclusions:

• The identified novel LDL receptor gene mutation serves as a specific genetic marker for heterozygous FH.
• Molecular genetic testing, specifically SSCP, provides accurate diagnosis for FH within families.
• Genetically validated criteria are essential for precise early diagnosis of familial hypercholesterolemia.