Alström Gene Variants May Also Raise Heart Attack Risk, Study in Chinese Finds

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by Joana Carvalho |

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Two variants of the Alström syndrome 1 (ALMS1) gene can increase the risk of heart attack in Chinese people with early onset coronary artery disease (CAD), a study reports.

The study, “Association between ALMS 1 variants and early-onset coronary artery disease: a case-control study in Chinese population,” was published in the journal Bioscience Reports.

ALMS1 is a gene that provides instructions to make a protein found at low levels in most body tissues. Although its exact functions are still unclear, it is known that mutations in ALMS1 can lead to a rare form of genetic obesity known as Alström syndrome.

A previous genome-wide study found that two common ALMS1 gene variants were linked to an increased risk of heart attack (myocardial infarction) in a Japanese population. One of these variants, called rs6748040, is thought to affect the gene’s activity as it is located on its promoter. The second, located on its first exon, is thought to change the sequence and function of the resulting protein.

The genome is the group of all the genes found in human DNA; a gene’s promoter is a region that controls its activity, and an exon is a portion that contains instructions to make a protein.

Researchers examined the sequence of the ALMS1 gene in Chinese with early onset CAD to investigate if the two previously reported mutations could also be associated with an increased risk of myocardial infarction in this population.

A total of 1,252 patients (mean age of 43.88, 91.7% men), who visited The Affiliated Hospital of Qingdao University between January 2013 and February 2019, had their blood drawn for DNA isolation and genetic analyses.

An identical procedure was carried out on 1,378 age- and sex-matched individuals without any signs of heart disease, who served as controls.

About half (50.8%) of the individuals with early onset CAD already had a myocardial infarction.

Statistical analyses found that the rs6748040 variant was associated with a higher risk of a heart attack. This was true for all genetic models used.

Additional analyses performed after taking into account participants’ age, sex, and comorbidities also found that the A allele of this variant was an independent risk factor for early onset myocardial infarction. (Alleles are different versions of the same gene.)

With the second ALMS1 variant, investigators discovered that individuals who had 14 repeats of the amino acid glutamic acid encoded in the first exon of the gene were at an 1.61-times greater risk of having a myocardial infarction. (Amino acids are the building blocks of proteins.)

In contrast, those with 17 repeats of glutamic acid in the same region were at a lower risk (0.68-times lower) of an early onset myocardial infarction.

No associations were found between any of the two ALMS1 genetic variants and the risk of early onset CAD.

“In conclusion, we observed that the two variants of the ALMS1 gene were significantly associated with the risk of early-onset MI [myocardial infarction]. However, the specific molecular pathological [disease] mechanism needs to be clarified in the following studies,” the scientists concluded.

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