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Modifier Genes in Microcephaly: A Report on WDR62 , CEP63 , RAD50 and PCNT Variants Exacerbating Disease Caused by Biallelic Mutations of ASPM and CENPJ .

Authors :
Makhdoom EUH
Waseem SS
Iqbal M
Abdullah U
Hussain G
Asif M
Budde B
Höhne W
Tinschert S
Saadi SM
Yousaf H
Ali Z
Fatima A
Kaygusuz E
Khan A
Jameel M
Khan S
Tariq M
Anjum I
Altmüller J
Thiele H
Höning S
Baig SM
Nürnberg P
Hussain MS
Source :
Genes [Genes (Basel)] 2021 May 13; Vol. 12 (5). Date of Electronic Publication: 2021 May 13.
Publication Year :
2021

Abstract

Congenital microcephaly is the clinical presentation of significantly reduced head circumference at birth. It manifests as both non-syndromic-microcephaly primary hereditary (MCPH)-and syndromic forms and shows considerable inter- and intrafamilial variability. It has been hypothesized that additional genetic variants may be responsible for this variability, but data are sparse. We have conducted deep phenotyping and genotyping of five Pakistani multiplex families with either MCPH ( n = 3) or Seckel syndrome ( n = 2). In addition to homozygous causal variants in ASPM or CENPJ , we discovered additional heterozygous modifier variants in WDR62, CEP63, RAD50 and PCNT -genes already known to be associated with neurological disorders. MCPH patients carrying an additional heterozygous modifier variant showed more severe phenotypic features. Likewise, the phenotype of Seckel syndrome caused by a novel CENPJ variant was aggravated to microcephalic osteodysplastic primordial dwarfism type II (MOPDII) in conjunction with an additional PCNT variant. We show that the CENPJ missense variant impairs splicing and decreases protein expression. We also observed centrosome amplification errors in patient cells, which were twofold higher in MOPDII as compared to Seckel cells. Taken together, these observations advocate for consideration of additional variants in related genes for their role in modifying the expressivity of the phenotype and need to be considered in genetic counseling and risk assessment.

Details

Language :
English
ISSN :
2073-4425
Volume :
12
Issue :
5
Database :
MEDLINE
Journal :
Genes
Publication Type :
Academic Journal
Accession number :
34068194
Full Text :
https://doi.org/10.3390/genes12050731