Basinko, Audrey, Douet‐Guilbert, Nathalie, Parent, Philippe, Blondin, Gilles, Mingam, M., Monot, Françoise, Morel, Frédéric, Le Bris, Marie‐Josée, and De Braekeleer, Marc
This 15‐month boy was expressed at the cytogenetic laboratory because of psychomotor development delay. He was tall and had plagiocephaly, micrognathia, high nasal bridge, anteverted nostrils and pectus excavatum. A 46,XY,del(4)(p16.1p16.3) karyotype was found using high‐resolution R‐banding technique. FISH studies using the LSI Wolf–Hirschhorn dual color 4p16.3 and the TelVysion 4p probes showed no deletion. Using BACs, the distal breakpoint was located in 4p16.3, between RP11‐165K4 and RP11‐717M10 and the proximal breakpoint in 4p15.33, between RP11‐74M11 and RP11‐1J7; therefore, approximately 7.96 Mb of the short arm were deleted. The maternal karyotype showed the same deletion, but in a mosaic status. Two distinct phenotypes have been recognized on the basis of the chromosomal bands involved in 4p deletion: the Wolf–Hirschhorn syndrome (WHS) and a proximal 4p deletion syndrome (4p15.2–p15.32). Our observation confirms that the basic WHS phenotype maps distally to this region. © 2008 Wiley‐Liss, Inc.