A new homozygous nonsense mutation in LAMA3A underlying laryngo-onycho-cutaneous syndrome.

[junctional epidermolysis bullosa]

Laryngo-onycho-cutaneous (LOC ) syndrome is a subtype of autosomal recessive junctional epidermolysis bullosa in which there is prominent skin and mucosal granulation tissue that can lead to delayed wound healing , laryngeal obstruction and blindness . Thus far , all cases are of Punjabi ancestry and have been shown to result from a founder mutation in the LAMA 3 gene , notably involving a single nucleotide insertion mutation in exon 39 , which is specific to the LAMA 3 A (designated exon 1 of LAMA 3 A ) and not the LAMA 3 B 1 or LAMA 3 B 2 isoforms . Here , we describe a new pedigree with LOC syndrome . Affected individuals (from Iran ) have the characteristic clinicopathological and molecular features of LOC syndrome : prominent granulation tissue (especially affecting the eyes ), normal intensity laminin-332 immunostaining at the dermal-epidermal junction , and autosomal recessive mutations in the LAMA 3 A -specific exon . The pathogenic mutation is a homozygous nonsense mutation , designated p .Gln 57 X , which just affects the laminin-α 3 a transcript . These findings therefore expand the molecular basis of LOC syndrome .