Late onset Pompe disease- new genetic variant: Case report
Pompe’s disease (acidmaltase deficiency, glycogen storage disease type II) is an autosomal recessive disorder caused by a deficiency of lysosomal acid-1, 4-glucosidase, resulting in excessive accumulation of glycogen in the lysosomes and cytoplasm of all tissues, most notably in skeletal muscles. A case is presented of late-onset Pompe’s disease with progressive respiratory failure for about 2 years requiring constant Oxygen supplementation. On physical exams except weight loss and breathlessness everything else was normal. Alpha glucosidase enzyme activity was reduced 22 (56-296). GAA gene mutation showed a heterozygous missence variation in exon 9 of the GAA gene (chr17.78083769;C>C/G; Depth:141x) that results in the amino acid substitution of Arginine for Proline at codon 451 (p.Pro451Arg:ENST00000302262) was detected. The variant c.1352C>C/G (p.Pro451Arg) detected had an autosomal recessive inheritance pattern. This mutation has not been reported before and it presents with severe progressive respiratory failure. The patient was not given enzyme replacement therapy due to cost but received high protein therapy and Oxygen supplementation using Oxygen extractor machine. She is worsening due to respiratory failure.
Conclusion: This is a new genetic variant isolated of late-onset Pompe disease which presents with almost pure progressive respiratory failure.