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

Muzammil A. Khan, Verena M. Rupp, Meritxell Orpinell, Muhammad S. Hussain, Janine Altmüller, Michel O. Steinmetz, Christian Enzinger, Holger Thiele, Wolfgang Höhne, Gudrun Nürnberg, Shahid M. Baig, Muhammad Ansar, Peter Nürnberg, John B. Vincent, Michael R. Speicher, Pierre Gönczy, Christian Windpassinger

Research output: Contribution to journalArticlepeer-review

59 Citations (Scopus)

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 PISAdomain 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.

Original languageEnglish
Pages (from-to)5940-5949
Number of pages10
JournalHuman Molecular Genetics
Volume23
Issue number22
DOIs
Publication statusPublished - 15 Nov 2014
Externally publishedYes

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