Mutation of TBCK causes a rare recessive developmental disorder.
OBJECTIVE
To characterize the underlying genetic defect in a family with 3 siblings affected by a severe, yet viable, congenital disorder.


METHODS
Extensive genetic and metabolic investigations were performed, and the affected children were imaged at different ages. Whole-genome genotyping and whole-exome sequencing were undertaken. A single large region (>8 Mb) of homozygosity in chromosome 4 (chr4:100,268,553-108,609,628) was identified that was shared only in affected siblings. Inspection of genetic variability within this region led to the identification of a novel mutation. Sanger sequencing confirmed segregation of the mutation with disease.


RESULTS
All affected siblings share homozygosity for a novel 4-bp deletion in the gene TBCK (NM_033115:c.614_617del:p.205_206del).


CONCLUSIONS
This finding provides the genetic cause of a severe inherited disease in a family and extends the number of mutations and phenotypes associated with this recently identified disease gene.
Department of Molecular Neuroscience (R.J.G., J.B.), Institute of Neurology; MRC Laboratory for Molecular Cell Biology (R.B., S.E.M.), University College London; Manchester Centre for Genomic Medicine (D.D.), University of Manchester and Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust; Royal Preston Hospital (C.d.G.), Genetics and Genomics Medicine Programme (S.E.M.), UCL Institute of Child Health and Department of Genetics, Evolution and Environment, University College London, UK.
Rita J
RJ
Guerreiro
Department of Molecular Neuroscience (R.J.G., J.B.), Institute of Neurology; MRC Laboratory for Molecular Cell Biology (R.B., S.E.M.), University College London; Manchester Centre for Genomic Medicine (D.D.), University of Manchester and Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust; Royal Preston Hospital (C.d.G.), Genetics and Genomics Medicine Programme (S.E.M.), UCL Institute of Child Health and Department of Genetics, Evolution and Environment, University College London, UK.
Rachel
R
Brown
Department of Molecular Neuroscience (R.J.G., J.B.), Institute of Neurology; MRC Laboratory for Molecular Cell Biology (R.B., S.E.M.), University College London; Manchester Centre for Genomic Medicine (D.D.), University of Manchester and Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust; Royal Preston Hospital (C.d.G.), Genetics and Genomics Medicine Programme (S.E.M.), UCL Institute of Child Health and Department of Genetics, Evolution and Environment, University College London, UK.
Donnai
D
Dian
Department of Molecular Neuroscience (R.J.G., J.B.), Institute of Neurology; MRC Laboratory for Molecular Cell Biology (R.B., S.E.M.), University College London; Manchester Centre for Genomic Medicine (D.D.), University of Manchester and Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust; Royal Preston Hospital (C.d.G.), Genetics and Genomics Medicine Programme (S.E.M.), UCL Institute of Child Health and Department of Genetics, Evolution and Environment, University College London, UK.
Christian
C
de Goede
Department of Molecular Neuroscience (R.J.G., J.B.), Institute of Neurology; MRC Laboratory for Molecular Cell Biology (R.B., S.E.M.), University College London; Manchester Centre for Genomic Medicine (D.D.), University of Manchester and Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust; Royal Preston Hospital (C.d.G.), Genetics and Genomics Medicine Programme (S.E.M.), UCL Institute of Child Health and Department of Genetics, Evolution and Environment, University College London, UK.
Jose
J
Bras
Department of Molecular Neuroscience (R.J.G., J.B.), Institute of Neurology; MRC Laboratory for Molecular Cell Biology (R.B., S.E.M.), University College London; Manchester Centre for Genomic Medicine (D.D.), University of Manchester and Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust; Royal Preston Hospital (C.d.G.), Genetics and Genomics Medicine Programme (S.E.M.), UCL Institute of Child Health and Department of Genetics, Evolution and Environment, University College London, UK.
Sara E
SE
Mole