There appears to be a correlation between genotype and phenotype in patients with Pompe disease, according to a new study conducted on 7 Mexican children and published in the scientific journal Gaceta Médica de México.

The aim of the study was to describe the genotype and characteristics of Mexican patients with infantile-onset Pompe disease.

The team of researchers led by Imelda Vergara-Sánchez from the Department of Pediatric Neurology, Mexican Social Security Institute, in Yucatán, Mexico, analyzed patients with the disease, confirmed based on acid alpha-glucosidase (GAA) enzyme activity and GAA gene analysis.  


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The patients’ median age at the time of symptom onset was 4 months. They were diagnosed with the disease at a median age of 8 months. 

Read more about the types of Pompe disease

They all had cardiomyopathy and 4 of them died before age 1. These 4 patients were negative for cross-reactive immunological material (CRIM), which is a measure of natural GAA production. They also had mutations in the GAA gene that predicted severe disease.

The remaining 3 patients lived passed age 1 with enzyme replacement therapy, with 1 of them surviving for almost 5 years. These 3 patients had pathogenic variants in the GAA gene that predicted potentially less severe disease and were positive for CRIM. (CRIM is also an important factor affecting patients’ response to enzyme replacement therapy).

“There was a good correlation between genotype and phenotype in children with Pompe disease,” the researchers concluded.

Pompe disease is a rare genetic metabolic disorder caused by a deficiency or absence of the GAA enzyme, the role of which is to cleave glycogen into glucose. The disease is characterized by the accumulation of glycogen in tissues leading to their impairment. Enzyme replacement therapy is currently the only approved disease-modifying therapy for Pompe disease.

Reference

Sánchez-Sánchez LM, Ávila-Rejón C, Díaz-Martínez R, et al. Infantile-onset Pompe disease in seven Mexican children. Gac Med Mex. 2022;158(5):265-270. English. doi:10.24875/GMM.M22000694