1p35 deletion and PUM1 mutation

chromosome 1

1p35 deletion and PUM1 mutation discussed in a newly published article. Development of the nervous system is a complex process that is tightly regulated by protein levels and expression. One protein involved in this process is produced by a gene PUM1, located in 1p35, a region within the short arm of chromosome 1. Evidence suggests that loss of this gene creates an imbalance of the proteins mentioned above. Deletions 1p35 which involve PUM1 and mutations of this gene cause developmental delay, hyperactivity, smaller body size, infertility, and shortened lifespan.

This article analyzes patients with 1p35 deletions that include PUM1 to highlight the importance of this gene in neurological development, and to summarize the exact neurological symptoms resulting from loss of this gene. Of the fifteen patients described, nine had PUM1 loss as a result of a 1p35 deletion. All nine patients exhibited developmental delay. Eight of the nine had some form of language delay, seven had intellectual disability, six had ataxia (loss of control of bodily movements), and three had seizures.

Though the deletions in these nine patients varied in size and number of genes affected, PUM1 was missing in all cases. Within the deleted regions, no other genes have been associated with the neurodevelopmental issues described above. In cases where PUM1 is mutated, patients also exhibited developmental delay and other neurological abnormalities. This suggests that loss of this gene is the root of the symptoms.

The evidence above supports the idea that loss of PUM1 causes the neurodevelopmental problems found in persons with 1p35 deletions. PUM1 is important in development because the protein produced by this gene is involved in the regulation of six other major proteins, important in protein metabolism, angiogenesis (development of blood vessels), and cell-cycle regulation. Disruption of these processes can have a severe impact on the developing brain. More research needs to be conducted on the role of PUM1 in the brain, but the article gives enough evidence to support its effect on the neurological symptoms of a 1p35 deletion.

Gennarino, et al. “A mild PUM1 mutation is associated with adult-onset ataxia, whereas haploinsufficiency causes developmental delay and seizures”. Cell 2018, v. 172, 924-936.