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Genetic Analysis of Hereditary Transthyretin Ala97Ser Related Amyloidosis
06:33

Genetic Analysis of Hereditary Transthyretin Ala97Ser Related Amyloidosis

Published on: June 9, 2018

Two Spanish sibs with familial amyloidotic polyneuropathy homozygous for the V30M-TTR gene

M Munar-Qués1, J M López Domínguez, C Viader-Farré

  • 1Grupo de Estudio de la PAF, Mallorca, Spain.

Amyloid : the International Journal of Experimental and Clinical Investigation : the Official Journal of the International Society of Amyloidosis
|June 21, 2001
PubMed

Insights

Two Spanish siblings with familial amyloidotic polyneuropathy (FAP) showed aggressive sensorimotor syndrome due to homozygous V30M-TTR gene mutation. Clinical variations between siblings suggest genetic or environmental influences on FAP.

Area of Science:

  • Genetics
  • Neurology
  • Molecular Biology

Background:

  • Familial amyloidotic polyneuropathy (FAP) is a progressive, autosomal dominant disorder.
  • The V30M transthyretin (TTR) mutation is the most common cause of FAP worldwide.
  • Previous studies on FAP have primarily focused on heterozygous carriers of the V30M-TTR mutation.

Observation:

  • Two siblings with FAP homozygous for the V30M-TTR gene were identified in Spain.
  • Both siblings presented with a clinical picture similar to heterozygous FAP patients but with a more severe sensorimotor syndrome.
  • Notable clinical disparities were observed between the siblings regarding autonomic dysfunction, cranial nerve involvement, and renal complications.

Findings:

  • Homozygosity for the V30M-TTR mutation in FAP leads to a distinct clinical presentation with accelerated sensorimotor decline.
  • Genetic analysis confirmed homozygous V30M-TTR genotype in both affected siblings.
  • Protein analysis further corroborated the diagnosis and the specific genetic mutation.

Implications:

  • This case highlights the potential for significant clinical variability in FAP even within the same family and with the same homozygous mutation.
  • The observed differences suggest that non-genetic factors, such as environmental influences or other genetic modifiers, may play a role in modulating FAP phenotype.
  • Further research is warranted to elucidate the interplay between genetic background, environmental factors, and disease progression in homozygous FAP patients.

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