Open Access Research

A mutation in KIF7 is responsible for the autosomal recessive syndrome of macrocephaly, multiple epiphyseal dysplasia and distinctive facial appearance

Bassam R Ali1, Jennifer L Silhavy2, Nadia A Akawi1, Joseph G Gleeson2 and Lihadh Al-Gazali3*

Author Affiliations

1 Department of Pathology, Faculty of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates

2 Department of Paediatrics and Neurosciences, University of California, San Diego, USA

3 Department of Paediatrics, Faculty of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al-Ain, United Arab Emirates

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Orphanet Journal of Rare Diseases 2012, 7:27 doi:10.1186/1750-1172-7-27

Published: 15 May 2012

Abstract

Background

We previously reported the existence of a unique autosomal recessive syndrome consisting of macrocephaly, multiple epiphyseal dysplasia and distinctive facial appearance mapping to chromosome 15q26.

Methods

In this manuscript, we have used whole exome sequencing on two affected members of a consanguineous family with this condition and carried out detailed bioinformatics analysis to elucidate the causative mutation.

Results

Our analysis resulted in the identification of a homozygous p.N1060S missense mutation in a highly conserved residue in KIF7, a regulator of Hedgehog signaling that has been recently found to be causing Joubert syndrome, fetal hydrolethalus and acrocallosal syndromes. The phenotype in our patients partially overlaps with the phenotypes associated with those syndromes but they also exhibit some distinctive features including multiple epiphyseal dysplasia.

Conclusions

We report the first missense homozygous disease-causing mutation in KIF7 and expand the clinical spectrum associated with mutations in this gene to include multiple epiphyseal dysplasia. The missense nature of the mutation might account for the unique presentation in our patients.

Keywords:
KIF7; Acrocallosal; Joubert; Sonic hedgehog; Dysmorphism; Multiple epiphyseal dysplasia; Fetal hydrolethalus