Homozygosity for a frequent and weakly penetrant predisposing allele at the RET locus in sporadic Hirschsprung disease. Issue 3 (2nd March 2005) - Pelet, A; de Pontual, L; Clément-Ziza, M; Salomon, R; Mugnier, C; Matsuda, F; Lathrop, M; Munnich, A; Feingold, J; Lyonnet, S; Abel, L; Amiel, J