Truncation of POC1A associated with short stature and extreme insulin resistance.


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Authors
Chen, Jian-Hua 
Segni, Maria 
Payne, Felicity 
Huang-Doran, Isabel  ORCID logo  https://orcid.org/0000-0002-0573-6557
Sleigh, Alison 
Abstract

We describe a female proband with primordial dwarfism, skeletal dysplasia, facial dysmorphism, extreme dyslipidaemic insulin resistance and fatty liver associated with a novel homozygous frameshift mutation in POC1A, predicted to affect two of the three protein products of the gene. POC1A encodes a protein associated with centrioles throughout the cell cycle and implicated in both mitotic spindle and primary ciliary function. Three homozygous mutations affecting all isoforms of POC1A have recently been implicated in a similar syndrome of primordial dwarfism, although no detailed metabolic phenotypes were described. Primary cells from the proband we describe exhibited increased centrosome amplification and multipolar spindle formation during mitosis, but showed normal DNA content, arguing against mitotic skipping, cleavage failure or cell fusion. Despite evidence of increased DNA damage in cells with supernumerary centrosomes, no aneuploidy was detected. Extensive centrosome clustering both at mitotic spindles and in primary cilia mitigated the consequences of centrosome amplification, and primary ciliary formation was normal. Although further metabolic studies of patients with POC1A mutations are warranted, we suggest that POC1A may be added to ALMS1 and PCNT as examples of centrosomal or pericentriolar proteins whose dysfunction leads to extreme dyslipidaemic insulin resistance. Further investigation of links between these molecular defects and adipose tissue dysfunction is likely to yield insights into mechanisms of adipose tissue maintenance and regeneration that are critical to metabolic health.

Description
Keywords
POC1A, centriole, centrosome, diabetes, dyslipidaemia, insulin resistance, primary cilium, short stature, skeletal dysplasia, Adult, Amino Acid Sequence, Body Height, Cell Cycle, Cell Cycle Proteins, Centrioles, Centrosome, Cytoskeletal Proteins, Dwarfism, Facies, Fatty Liver, Female, Frameshift Mutation, Humans, Insulin Resistance, Mitosis, Molecular Sequence Data, Protein Isoforms, Proteins, Sequence Alignment, Spindle Apparatus
Journal Title
J Mol Endocrinol
Conference Name
Journal ISSN
0952-5041
1479-6813
Volume Title
55
Publisher
Bioscientifica
Sponsorship
Medical Research Council (G0701532)
Wellcome Trust (095515/Z/11/Z)
Medical Research Council (MC_UU_12012/5)
Wellcome Trust (100574/Z/12/Z)
Medical Research Council (MC_UU_12012/5/B)
Wellcome Trust (098498/Z/12/Z)
Wellcome Trust (091551/Z/10/A)
Wellcome Trust (091310/Z/10/Z)
This work was supported by the Wellcome Trust [grant numbers WT098498, WT098051,WT095515, and WT091310]; the Medical Research Council [MRC_MC_UU_12012/5]; the United Kingdom National Institute for Health Research (NIHR) Cambridge Biomedical Research Centre.