Homozygosity mapping and targeted genomic sequencing reveal the gene responsible for cerebellar hypoplasia and quadrupedal locomotion in a consanguineous kindred

Suleyman Gulsuner, Ayse Begum Tekinay, Katja Doerschner, Huseyin Boyaci, Kaya Bilguvar, Hilal Unal, Aslihan Ors, O. Emre Onat, Ergin Atalar, A. Nazli Basak, Haluk Topaloglu, Tulay Kansu, Meliha Tan, Uner Tan, Murat Gunel, Tayfun Ozcelik

Research output: Contribution to journalArticlepeer-review

Abstract

The biological basis for the development of the cerebro-cerebellar structures required for posture and gait in humans is poorly understood. We investigated a large consanguineous family from Turkey exhibiting an extremely rare phenotype associated with quadrupedal locomotion, mental retardation, and cerebro-cerebellar hypoplasia, linked to a 7.1-Mb region of homozygosity on chromosome 17p13.1-13.3. Diffusion weighted imaging and fiber tractography of the patients' brains revealed morphological abnormalities in the cerebellum and corpus callosum, in particular atrophy of superior, middle, and inferior peduncles of the cerebellum. Structural magnetic resonance imaging showed additional morphometric abnormalities in several cortical areas, including the corpus callosum, precentral gyrus, and Brodmann areas BA6, BA44, and BA45. Targeted sequencing of the entire homozygous region in three affected individuals and two obligate carriers uncovered a private missense mutation, WDR81 p.P856L, which cosegregated with the condition in the extended family. The mutation lies in a highly conserved region of WDR81, flanked by an N-terminal BEACH domain and C-terminal WD40 beta-propeller domains. WDR81 is predicted to be a transmembrane protein. It is highly expressed in the cerebellum and corpus callosum, in particular in the Purkinje cell layer of the cerebellum. WDR81 represents the third gene, after VLDLR and CA8, implicated in quadrupedal locomotion in humans.

Original languageEnglish (US)
Pages (from-to)1995-2003
Number of pages9
JournalGenome Research
Volume21
Issue number12
DOIs
StatePublished - Dec 2011
Externally publishedYes

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)

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