Scientists Identify a New Gene Leading to Profound Neurodevelopmental Delays
Variants of a novel gene, DPH5, was suggested to be the real culprit of embryonic death and severe neurodevelopmental delays. The research team led by UC Davis geneticist Suma Shankar has revealed the abnormal form of DPH5 will lead to DPH5-related diphthamide-deficiency syndrome, which affects the process of ribosomal protein synthesis. The findings were published in Genetics in Medicine.
How Does it Relate?
DPH5 is one of the genes essential for the synthesis of diphthamide, which is a modified form of amino acid histidine. Diphthamide is known to ensure translation fidelity, thus the dysfunction of DPH5 which disrupts diphthamide level might affect messenger RNA translation and ribosomal protein synthesis, hence leading to embryonic lethality, neurodevelopmental delays, and even affecting organ function.
In 2018, the genetic analysis results of two Syrian siblings with the syndrome of severe neurodevelopmental delays showed that their DPH5 gene had a ‘variant of uncertain significance’. The DPH5 variant is later on identified in five kids from different regions, who share neurodevelopmental delays, profound disabilities, heart abnormalities, and feeding difficulties in common.
Several models were developed to confirm the role of the DPH5 variant. One of the most representative is the mouse model with altered DPH5 gene reference to the changes found in the first family. The DPH5 variant in both gene copies is proven to be deadly, while the only alive newborn mouse had a shorter lifespan of 24 days only. The syndromes shown including impaired growth, craniofacial deformation, and multisystem dysfunction are all similar to that of humans.
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Prenatal Genetic Testing is Encouraged
The study concluded that the syndrome is an autosomal recessive disorder, which means both parents must carry the gene mutation to have a child with a DPH5-related condition.
“Parents with DPH5 variants now know that the chance of having a child with the disorder is one out of four. They may elect to do prenatal genetic testing before or during pregnancy,” according to the leading scientist, Suma Shankar, professor in the Departments of Pediatrics and Ophthalmology and faculty at the UC Davis MIND Institute.
DPH5 variant may become the new benchmark in prenatal screening, while further studies are required.
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