Summary
Pierson syndrome is characterised by the association of congenital nephrotic syndrome and ocular anomalies with microcoria. Less than 30 cases have been described in the literature so far. Pierson syndrome results in proteinuria with nephrotic syndrome and histological lesions marked by diffuse mesangial sclerosis. Ocular anomalies are present from birth and include microcoria (small pupils that are not responsive to light) associated with absence of the pupillary dilator muscle in the iris, ciliary muscle atrophy, and abnormal eye development with lens-shape, retinal and corneal anomalies. Marked muscle hypotonia, movement disorders and psychomotor delay have also been reported. The disease is transmitted as an autosomal recessive trait. Mutations in the LAMB2 gene (3p21) encoding laminin beta 2 have been identified. Laminin beta 2 is expressed in the glomerular basement membrane at the neuromuscular junctions, as well as in the intraocular muscles, lens and retina. The diagnosis should be suspected on the basis of the association of early-onset nephrotic syndrome and microcoria. Prenatal diagnosis may be suspected following ultrasound detection of hyperechogenic kidneys and oligohydramnios. Antenatal diagnosis may be offered to families in which the disease-causing mutation has already been identified. The prognosis is severe, with most patients progressing towards renal failure within the first days or months of life. *Author: Prof. P. Niaudet (February 2007)*.
