Thread by @thatdnaguy

#ASHG20 VF
Impaired eIF5A function causes a craniofacial-neurodevelopmental syndrome that is partially rescued in model systems by spermidine.
Victor Faundes.

#ASHG20 VF by trio whole exome find de novo heterozygous frameshift in EF15A in a patient with a syndrome similar to Kabuki syndrome.

#ASHG20 VF Used Gene Matcher to find additional patients with similar phenotypic featurs. Find additional EIF5A variants in these patients. Developmental delay. Microcephaly, micrognathia.

#ASHG20 VF What does EIF5A? Essential to resolve ribosomal stalling caused by polyproline tracts (PPT). What is the mechanism for the variants?

#ASHG20 VF Transformed blood cells from patient with p.R109Tfs*8 variant. Looked at lymphocyte cell lines. RT-qPCR showed lower level of EIF5A in the patient cells.

#ASHG20 VF Suggests that the effect is haploinsufficiency. Did growth curves in yeast with human EIF5A [ I think that's right, some slight technical issues with sound ]

#ASHG20 VF p.T48N and p.G106R impaired growth. Frameshift not viable. p.E122K didn't change growth.

#ASHG20 VF What do the variants do with respect to the ribosome? The variant alleles have reduced eIF5A associted with the 80S subunit. Increase in free 60S subunit. Increase in the 60S / 80S ratio.

#ASHG20 VF Looked on western. total levels of protein reduced with p.G106R and p.E122K. Hypusinated eIF5A reduced by p.T48N.

#ASHG20 VF Made some poly-proline reporter constructs. p.T48N and p.G106R decreased synthesis of both. p.E122K reduced slightly the synthesis of one. Is reduced protein expression the method?

#ASHG20 VF Look at genes known to be associated with microcephaly. Test for poly-proline tracts. They are 27% more enriched for poly-proline tracts when compared to genes not associated with microcephaly. P = 0.0057.

#ASHG20 VF Is there a way to rescue? Spermidine is the substrate for hypusine and can partially replace eIF5A function. Add spermidine to media for yeast studies. See improvement toward wildtype with regard to growth rates.

#ASHG20 VF eif5A morpholino causes micrognathia in zebrafish. Partially rescued by the addition of spermidine.