Alternative titles; symbolsCHROMOSOME 19 OPEN READING FRAME 56; C19ORF56ASTERIXHGNC Approved Gene Symbol: WDR83OSCytogenetic location: 19p13.13 Genomic coord...
Alternative titles; symbols
HGNC Approved Gene Symbol: WDR83OS
Cytogenetic location: 19p13.13 Genomic coordinates (GRCh38): 19:12,668,070-12,671,022 (from NCBI)
▼ Cloning and Expression
Pinho et al. (2011) cloned chicken Wdr83os, which they called Asterix. Asterix is highly conserved across all vertebrates, as well as invertebrates. In situ hybridization showed Asterix expression in developing nervous system of chick embryos. The transcripts appeared in the prospective neural plate during gastrulation and remained expressed in the neural plate, neural tube, and placodes at least until stage 14.
By database analysis, Pinho et al. (2011) mapped the WDR83OS gene to chromosome 19.
Gross (2019) mapped the WDR83OS gene to chromosome 19p13.3 based on an alignment of the WDR83OS sequence (GenBank BC042919) with the genomic sequence (GRCh38).
▼ Gene Function
Using a time-course study, Pinho et al. (2011) identified Asterix as an early response gene to neural-inducing signals from the organizer, the Hensen node, in chick embryos. Neuronal secreted factor FGF (see 600483) was necessary and sufficient for induction of Asterix.
Chitwood and Hegde (2020) identified the PAT complex, an abundant obligate heterodimer of the widely conserved endoplasmic reticulum (ER)-resident membrane proteins CCDC47 (618260) and Asterix. The PAT complex engages nascent transmembrane domains that contain unshielded hydrophilic side chains within the lipid bilayer, and it disengages concomitant with substrate folding. Cells that lack either subunit of the PAT complex show reduced biogenesis of numerous multispanning membrane proteins. Thus, Chitwood and Hegde (2020) concluded the PAT complex is an intramembrane chaperone that protects transmembrane domains during assembly to minimize misfolding of multispanning membrane proteins and maintain cellular protein homeostasis.
▼ Molecular Genetics
For discussion of a possible association between familial intrahepatic cholestasis (see 211600) and mutation in the WDR83OS gene, see 619309.0001.
▼ ALLELIC VARIANTS ( 1 Selected Example):
.0001 VARIANT OF UNKNOWN SIGNIFICANCE
This variant is classified as a variant of unknown significance because its contribution to familial intrahepatic cholestasis (see 211600) has not been confirmed.
By autozygosity mapping followed by exome sequencing in 3 sibs from a consanguineous family (family 7) who presented with a consistent combination of hypercholanemia (high total serum bile acids and ALP with normal ALT, AST, and total bilirubin), intractable itching, impaired intellectual development (IQ 45), progressive microcephaly, dysmorphic facies, short stature, and genital abnormalities, Maddirevula et al. (2019) identified homozygosity for a splice donor site mutation (c.156+1G-T, NM_016145.3), resulting in a frameshift and premature termination. The mutation was confirmed by RT-PCR using RNA from patient lymphoblasts (r.51_156del; Arg17SerfsTer2). The genital abnormalities included large clitoris in 1 affected girl, and undescended testes status after orchidopexy in the affected boy.