Heimler Syndrome Is Caused by Hypomorphic Mutations in the Peroxisome-Biogenesis Genes PEX1 and PEX6

Ilham Ratbi, Kim D. Falkenberg, Manou Sommen, Nada Al-Sheqaih, Soukaina Guaoua, Geert Vandeweyer, Jill E. Urquhart, Kate E. Chandler, Simon G. Williams, Neil A. Roberts, Mustapha El Alloussi, Graeme C. Black, Sacha Ferdinandusse, Hind Ramdi, Audrey Heimler, Alan Fryer, Sally-Ann Lynch, Nicola Cooper, Kai Ren Ong, Claire E. L. SmithChristopher F. Inglehearn, Alan J. Mighell, Claire Elcock, James A. Poulter, Marc Tischkowitz, Sally J. Davies, Abdelaziz Sefiani, Aleksandr A. Mironov, William G. Newman, Hans R. Waterham, Guy van Camp

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Heimler syndrome (HS) is a rare recessive disorder characterized by sensorineural hearing loss (SNHL), amelogenesis imperfecta, nail abnormalities, and occasional or late-onset retinal pigmentation. We ascertained eight families affected by HS and, by using a whole-exome sequencing approach, identified biallelic mutations in PEX1 or PEX6 in six of them. Loss-of-function mutations in both genes are known causes of a spectrum of autosomal-recessive peroxisome-biogenesis disorders (PBDs), including Zellweger syndrome. PBDs are characterized by leukodystrophy, hypotonia, SNHL, retinopathy, and skeletal, craniofacial, and liver abnormalities. We demonstrate that each HS-affected family has at least one hypomorphic allele that results in extremely mild peroxisomal dysfunction. Although individuals with HS share some subtle clinical features found in PBDs, the diagnosis was not suggested by routine blood and skin fibroblast analyses used to detect PBDs. In conclusion, our findings define HS as a mild PBD, expanding the pleiotropy of mutations in PEX1 and PEX6
Original languageEnglish
Pages (from-to)535-545
JournalAmerican journal of human genetics
Issue number4
Publication statusPublished - 2015

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