Variable phenotype of Pierson syndrome.

Area of Science:

• Genetics
• Ophthalmology
• Nephrology

Background:

• Pierson syndrome is a rare genetic disorder linked to the LAMB2 gene, typically presenting with congenital nephrotic syndrome and bilateral microcoria.
• The laminin beta2 chain, encoded by LAMB2, is crucial for glomerular basement membrane (GBM) structure and function.

Observation:

• Two Pierson syndrome cases with atypical phenotypes are presented: one with infantile nephrotic syndrome and preserved renal function, the other with isolated nephrotic syndrome and later ocular complications.
• Electron microscopy revealed irregular lamellation of the GBM in both patients, a significant ultrastructural finding.

Findings:

• Genetic analysis identified distinct LAMB2 mutations in both patients, including frame-shifting deletions and a missense mutation.
• The study demonstrates wide phenotypic variability in Pierson syndrome, with discordant severity between renal and ocular manifestations.
• Genotype-phenotype correlations are suggested, alongside potential roles for unknown genetic or environmental modifiers.

Implications:

• Ultrastructural GBM changes serve as a valuable diagnostic marker for Pierson syndrome.
• Understanding the broad phenotypic spectrum and potential modifiers is crucial for accurate diagnosis and management of Pierson syndrome.
• Further research into genotype-phenotype correlations and modifier roles can improve prognostic accuracy and therapeutic strategies.