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Homozygous missense variants in YKT6 result in loss of function and are associated with developmental delay, with or without severe infantile liver disease and risk for hepatocellular carcinoma
Journal article   Open access   Peer reviewed

Homozygous missense variants in YKT6 result in loss of function and are associated with developmental delay, with or without severe infantile liver disease and risk for hepatocellular carcinoma

Mengqi Ma, Mythily Ganapathi, Yiming Zheng, Kai-Li Tan, Oguz Kanca, Kevin E Bove, Norma Quintanilla, Sebnem O Sag, Sehime G Temel, Charles A LeDuc, …
Genetics in medicine, Vol.26(7), 101125
07/2024
DOI: 10.1016/j.gim.2024.101125
PMCID: PMC11335040
PMID: 38522068
url
https://doi.org/10.1016/j.gim.2024.101125View
Published (Version of record) Open Access

Abstract

YKT6 plays important roles in multiple intracellular vesicle trafficking events but has not been associated with Mendelian diseases. We report three unrelated individuals with rare homozygous missense variants in YKT6 who exhibited neurological disease with or without a progressive infantile liver disease. We modeled the variants in Drosophila. We generated wild-type and variant genomic rescue constructs (GRs) of the fly ortholog dYkt6 and compared their ability in rescuing the loss-of-function phenotypes in mutant flies. We also generated a dYkt6 allele to assess the expression pattern of dYkt6. Two individuals are homozygous for YKT6 [NM_006555.3:c.554A>G p.(Tyr185Cys)] and exhibited normal prenatal course followed by failure to thrive, developmental delay and progressive liver disease. Haplotype analysis identified a shared homozygous region flanking the variant, suggesting a common ancestry. The third individual is homozygous for YKT6 [NM_006555.3:c.191A>G p.(Tyr64Cys)] and exhibited neurodevelopmental disorders and optic atrophy. Fly dYkt6 is essential and is expressed in the fat body (analogous to liver) and central nervous system. Wild-type GR can rescue the lethality and autophagic flux defects whereas the variants are less efficient in rescuing the phenotypes. The YKT6 variants are partial loss-of-function alleles and the p.(Tyr185Cys) is more severe than p.(Tyr64Cys).
Failure To Thrive autophagy Drosophila Syrian Christians of India fat body

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