A milder variant of Pierson syndrome

Congenital nephrotic syndrome (CNS) comprises a heterogeneous group of conditions having in common the disruption of normal glomerular permselectivity, and it carries a poor prognosis, with most patients progressing to end-stage renal disease. Recently, mutations in the LAMB2 gene encoding laminin β2 were described as the cause of Pierson syndrome, which is characterized by CNS and a complex ocular maldevelopment with microcoria as the most prominent clinical features. Most affected children exhibit early onset of chronic renal failure, neurodevelopmental deficits, and blindness. We report on a patient with CNS, high-grade myopia, and minor structural eye anomalies, including remnants of pupillary membranes, but no microcoria. The patient had not developed renal failure by the age of 16 months, and he showed no neurodevelopmental deficits. He was identified to be homozygous for a novel LAMB2 missense mutation. 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.