Research Article

Pseudo deficiency of acid α-glucosidase: a challenge in the newborn screening for Pompe diseases

Published: December 01, 2017
Genet. Mol. Res. 16(4): gmr16039844 DOI: https://doi.org/10.4238/gmr16039844
Cite this Article:
D.Rojas Málaga, A.C.Brusius Facchin, K.Michelin Tirelli, T.M. Félix, J. Schulte, J. Pereira, E.Camargo Neto, C.Sampaio Filho, R. Giugliani (2017). Pseudo deficiency of acid α-glucosidase: a challenge in the newborn screening for Pompe diseases. Genet. Mol. Res. 16(4): gmr16039844. https://doi.org/10.4238/gmr16039844
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Abstract

When a low activity of acid α-glucosidase (GAA) is
found, particularly in newborn screening programs, to differentiate α-
glucosidase pseudo deficiency from true Pompe disease is important and
urgent, as the result generates parental stress and also because this
differentiation drives decisions related to the management of the case.
Here, we report a case of GAA pseudo deficiency detected in a newborn
screening performed by a private laboratory in Brazil. The confirmatory
laboratory investigation performed at our service showed reduction of
GAA activity on the dried blood spot, with inconclusive results when
GAA activity was assayed in leukocytes. Genotyping of the GAA gene
with next-generation sequencing revealed the common pathogenic
mutation c.-32-13T>G and the “pseudo deficiency allele” p.
[Gly576Ser; Glu689Lys], each one in heterozygous state and in trans.
This report illustrates the need of newborn screening programs to have
the adequate support to perform a comprehensive investigation
whenever an abnormality is found in the initial screening test.
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