Analbuminemia produced by a novel splicing mutation

Area of Science:

• Genetics
• Molecular Biology
• Biochemistry

Background:

• Analbuminemia is a rare autosomal recessive disorder characterized by extremely low or absent serum albumin.
• It results from various mutations in the human albumin gene, affecting albumin synthesis.
• This condition is typically identified in individuals who are homozygous or compound heterozygous for defective albumin gene alleles.

Observation:

• A Turkish infant presented with analbuminemia, exhibiting a significantly reduced albumin concentration of approximately 9.0 g/L.
• Genetic screening of the albumin gene revealed a homozygous T-->C transition at nucleotide 13381 in intron 11.
• This previously unreported mutation was named 'Bartin' after the patient's family's geographical origin.

Findings:

• The Bartin mutation disrupts the conserved GT dinucleotide at the 5' splice site of intron 11, leading to exon 11 skipping.
• Reverse transcription-PCR analysis of albumin mRNA confirmed the exon 11 skipping.
• The resulting frameshift in exon 12 creates a premature stop codon, yielding a truncated protein of 410 amino acids.

Implications:

• This study identifies a novel mutation responsible for analbuminemia, expanding the known spectrum of albumin gene defects.
• Understanding the molecular basis of analbuminemia aids in diagnosing and potentially managing this rare genetic disorder.
• The findings contribute to the broader understanding of gene splicing mechanisms and their role in human diseases.