To describe the prenatal findings in Pierson syndrome, a newly defined autosomal recessive entity, comprising congenital nephrotic syndrome (CNS) with diffuse mesangial sclerosis and distinct eye abnormalities due to LAMB2 mutations.
These findings demonstrate that the spectrum of LAMB2-associated disorders is broader than previously anticipated and includes congenital nephrotic syndrome without eye anomalies or with minor ocular changes different from those observed in Pierson syndrome.
These findings demonstrate that the spectrum of LAMB2-associated disorders is broader than previously anticipated and includes congenital nephrotic syndrome without eye anomalies or with minor ocular changes different from those observed in Pierson syndrome.
This observation, together with two recent reports on milder variants of Pierson syndrome, corroborates the concept that the clinical expression of Pierson syndrome is more variable than initially described, and that milder phenotypes may be related to hypomorphic LAMB2 alleles.
The most common mutations are in 4 genes, 3 of which are podocyte genes: NPHS1 (Finnish nephropathy), NPHS2 (podocin-induced focal segmental glomerulosclerosis), WT1 (diffuse mesangial sclerosis), and LAMB2 (Pierson syndrome).
The majority of disease-causing LAMB2 mutations are truncating, consistent with the hypothesis that loss of laminin beta2 function is the molecular basis of Pierson syndrome.
The majority of disease-causing LAMB2 mutations are truncating, consistent with the hypothesis that loss of laminin beta2 function is the molecular basis of Pierson syndrome.
Genetic diseases affecting laminin and type IV collagen synthesis also are presented, with an emphasis on mutations to LAMB2 (Pierson syndrome) and COL4A3, COL4A4, and COL4A5 (Alport syndrome), and their experimental mouse models.
LAMB2 mutations cause Pierson syndrome (OMIM 609049), an autosomal recessive genetic disease typically characterized by congenital nephrotic syndrome (CNS) and early onset renal failure, as well as bilateral microcoria.