A recurrent de novo ZSWIM6 variant in a Japanese patient with severe neurodevelopmental delay and frequent vomiting

Entry of ZSWIM4 to the nucleus is crucial for its inhibition of KIT and BMAL1 in gastrointestinal stromal tumors

BACKGROUND

Zinc finger SWIM-type containing 4 (ZSWIM4) is a zinc finger protein with its function largely uncharacterized. In this study, we aimed to investigate the role of ZSWIM4 in gastrointestinal stromal tumors (GISTs).

RESULTS

We found that ZSWIM4 expression is inhibited by the predominantly mutated protein KIT in GISTs, while conversely, ZSWIM4 inhibits KIT expression and downstream signaling. Consistent with the observation, ZSWIM4 inhibited GIST cell survival and proliferation in vitro. RNA sequencing of GISTs from KITV558A/WT mice and KITV558A/WT/ZSWIM4-/- mice showed that loss of ZSWIM4 expression increases the expression of circadian clock pathway member BMAL1 which contributes to GIST cell survival and proliferation. In addition, we found that KIT signaling increases the distribution of ZSWIM4 in the nucleus of GIST cells, and which is important for its inhibition of KIT and BMAL1. In agreement with the results in vitro, the in vivo studies showed that ZSWIM4 deficiency increases the tumorigenesis of GISTs in KITV558A/WT mice.

CONCLUSIONS

Taken together, our results revealed that the entry of ZSWIM4 to the nucleus is important for its inhibition of KIT and BMAL1, ultimately attenuating GIST tumorigenesis. The results provide a novel insight in the understanding of signal transduction in GISTs and lay strong theoretical basis for the advancement of GIST treatment.

Recurrent de novo pathogenic variant of WASF1 in a Japanese patient with neurodevelopmental disorder with absent language and variable seizures

A recurrent de novo pathogenic variant of WASF1, NM_003931:c.1516C>T [p.Arg506*], was identified in a 6-year-old female Japanese patient with severe developmental delay, hypotonia, hyperkinetic behavior, and distinctive facial features. The initial report of five adult patients with WASF1 variants was the only previous report regarding variants of this gene; this is the second such report, reaffirming that rare but recurrent truncating variants of WASF1 are associated with severe neurodevelopmental disorders.