Triple-A syndrome
Rare autosomal recessive disorder with achalasia, addisonianism, and alacrima.
Triple-A syndrome, also known as AAA syndrome, is a rare autosomal recessive congenital disorder first identified by Jeremy Allgrove and colleagues in 1978. It is characterized by the triad of achalasia, addisonianism (primary adrenal insufficiency), and alacrima (absence of tear secretion), with alacrima usually being the earliest manifestation. The disorder is progressive and can take years to develop the full clinical picture, with variability and heterogeneity in presentation.
- field
- Medical genetics
- known_for
- Triple-A syndrome (achalasia, addisonianism, alacrima)
- inheritance
- Autosomal recessive
- associated_gene
- AAAS gene (encodes ALADIN protein)
- chromosome_location
- 12q13
Lore & Background
Triple-A syndrome was first identified by Jeremy Allgrove and colleagues in 1978, and since then just over 100 cases have been reported. In most cases, there is no family history of the syndrome. The disorder is associated with mutations in the AAAS gene, which encodes the ALADIN protein, a component of the nuclear pore complex. Mutant ALADIN mis-localizes in the cytoplasm, causing selective failure of nuclear protein import and hypersensitivity to oxidative stress, as well as decreased nuclear import of DNA repair proteins such as aprataxin and DNA ligase I, potentially leading to cell death.
Reader's Guide
Triple-A syndrome is significant as a rare genetic disorder that illustrates the complex interplay between nuclear pore function, DNA repair, and multisystem disease. Its progressive nature and variable presentation—including neurodegeneration, autonomic dysfunction, and mild intellectual disability—highlight the challenges in diagnosis and management. The syndrome is typically managed symptomatically with hormone replacement for adrenal insufficiency, lubricating eye drops, and surgical intervention for achalasia. Early diagnosis, aided by genetic testing, can prevent morbidity and improve growth in children. The discovery of genotypic heterogeneity suggests that other genes and environmental factors may also contribute to the phenotype, underscoring the need for further research into the mechanisms of this disorder.
Did You Know?
- Alacrima (lack of tears) is usually the earliest manifestation of Triple-A syndrome.
- The disorder has been suggested to be called 4A syndrome due to the presence of neurodegeneration or autonomic dysfunction.
- The AAAS gene maps to human chromosome 12q13 near the type II keratin gene cluster.
- Female mice homozygously null for ALADIN are sterile.
More in Medical triads 1-24
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