Human Molecular Genetics Advance Access originally published online on April 10, 2008
Human Molecular Genetics 2008 17(14):2150-2159; doi:10.1093/hmg/ddn114
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Novel mutations in LHX3 are associated with hypopituitarism and sensorineural hearing loss
1 Genetics Unit, DGHA, Ministry of Health, Muscat, Sultanate of Oman 2 Developmental Endocrinology Research Group, Clinical and Molecular Genetics Unit 3 MRC-Wellcome Trust Human Developmental Biology Resource, Neural Development Unit 4 Clinical and Molecular Genetics Unit, Institute of Child Health, London, UK 5 Institute of Experimental Pediatric Endocrinology, Charite, Berlin, Germany 6 Pediatric Endocrine Unit, Royal Hospital, Muscat, Sultanate of Oman 7 Department of Endocrinology, Royal Manchester Children’s Hospital, Manchester, UK
* To whom correspondence should be addressed at: Clinical and Molecular Genetics Unit, Institute of Child Health, 30 Guilford Street, London WC1 N 1EH, UK. Tel: +44 2079052657; Fax: +44 2079052832; Email: m.dattani{at}ich.ucl.ac.uk
Received January 18, 2008; Revised March 20, 2008; Accepted April 8, 2008
Homozygous loss-of-function mutations in the transcription factor LHX3 have been associated with hypopituitarism with structural anterior pituitary defects and cervical abnormalities with or without restricted neck rotation. We report two novel recessive mutations in LHX3 in four patients from two unrelated pedigrees. Clinical evaluation revealed that all four patients exhibit varying degrees of bilateral sensorineural hearing loss, which has not been previously reported in association with LHX3 mutations, in addition to hypopituitarism including adrenocorticotropic hormone deficiency and an unusual skin and skeletal phenotype in one family. Furthermore, re-evaluation of three patients previously described with LHX3 mutations showed they also exhibit varying degrees of bilateral sensorineural hearing loss. We have investigated a possible role for LHX3 in inner ear development in humans using in situ hybridization of human embryonic and fetal tissue. LHX3 is expressed in defined regions of the sensory epithelium of the developing inner ear in a pattern overlapping that of SOX2, which precedes the onset of LHX3 expression and is known to be required for inner ear and pituitary development in both mice and humans. Moreover, we show that SOX2 is capable of binding to and activating transcription of the LHX3 proximal promoter in vitro. This study therefore extends the phenotypic spectrum associated with LHX3 mutations to encompass variable sensorineural hearing loss and suggests a possible interaction between LHX3 and SOX2 likely to be important for development of both the inner ear and the anterior pituitary in human embryonic development.
The authors wish it to be known that, in their opinion, the first two authors should be regarded as joint First Authors.