A missense mutation in the PISA domain of HsSAS-6 causes autosomal recessive primary microcephaly in a large consanguineous Pakistani family

Item Type:	Article
Title:	A missense mutation in the PISA domain of HsSAS-6 causes autosomal recessive primary microcephaly in a large consanguineous Pakistani family
Creators Name:	Khan, M.A. and Rupp, V.M. and Orpinell, M. and Hussain, M.S. and Altmüller, J. and Steinmetz, M.O. and Enzinger, C. and Thiele, H. and Höhne, W. and Nürnberg, G. and Baig, S.M. and Ansar, M. and Nürnberg, P. and Vincent, J.B. and Speicher, M.R. and Gönczy, P. and Windpassinger, C.
Abstract:	Asymmetric cell division is essential for normal human brain development. Mutations in several genes encoding centrosomal proteins that participate in accurate cell division have been reported to cause autosomal recessive primary microcephaly (MCPH). By homozygosity mapping including three affected individuals from a consanguineous MCPH family from Pakistan, we delineated a critical region of 18.53 Mb on Chromosome 1p21.3-1p13.1. This region contains the gene encoding HsSAS-6, a centrosomal protein primordial for seeding the formation of new centrioles during the cell cycle. Both next-generation and Sanger sequencing revealed a homozygous c.185T>C missense mutation in the HsSAS-6 gene, resulting in a p.Ile62Thr substitution within a highly conserved region of the PISA domain of HsSAS-6. This variant is neither present in any single-nucleotide polymorphism or exome sequencing databases nor in a Pakistani control cohort. Experiments in tissue culture cells revealed that the Ile62Thr mutant of HsSAS-6 is substantially less efficient than the wild-type protein in sustaining centriole formation. Together, our findings demonstrate a dramatic impact of the mutation p.Ile62Thr on HsSAS-6 function and add this component to the list of genes mutated in primary microcephaly.
Keywords:	Amino Acid Sequence, Asian People, Base Sequence, Cell Cycle Proteins, Exome, Microcephaly, Missense Mutation, Molecular Sequence Data, Pakistan, Pedigree, Sequence Alignment, Single Nucleotide Polymorphism, Tertiary Protein Structure
Source:	Human Molecular Genetics
ISSN:	0964-6906
Publisher:	Oxford University Press
Volume:	23
Number:	22
Page Range:	5940-5949
Date:	15 November 2014
Official Publication:	https://doi.org/10.1093/hmg/ddu318
PubMed:	View item in PubMed

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