[Severe form of juvenile type II glycogenosis in a compound-heterozygous boy (Tyr-292--> Cys/Arg-854-->Stop)].
BACKGROUND
Type II glycogenosis is a glycogen storage disease inherited as an autosomal recessive trait. This molecular and clinically heterogeneous condition is due to a deficiency in a lysosomal acid 1,4-alpha-glucosidase.


OBJECTIVE
To report the clinical, enzymatic and molecular characterization of a mulatto child, born to healthy Dominican mother and Caucasian father, affected by the juvenile phenotype form of type II glycogenosis.


METHODS
This 16-month-old male presented from 10 months with motor delay, limb-girdle hypotonia, prominence of calves, increased CPK value, mixed myotonic/myopathic pattern on EMG, intense glycogen muscle storage (775 micrograms/mg of protein) and severe deficiency of 1,4-alpha-glucosidase activity (< 0.03 mU/mg of protein). At 24 months he developed a rapidly progressive hypotonia and respiratory failure. The patient was found to be compound heretozygote for the novel mutation Tyr-292-->Cys, coming from the father, and Arg-854-->Stop, coming from the mother and previously reported in two Afroamerican patients, one with the adult phenotype and the other with the juvenile one.


CONCLUSIONS
The present case corresponds to a severe form of type II juvenile glycogenosis. The severity of this condition may be related to the observed mutations and the associated extremely low muscle enzymatic activity.
Castro-Gago
M
M
Departamento de Pediatria, Hospital General de Galicia, Santiago de Compostela, España. pdcastro@uscmail.usc.es
Eirís-Puñal
J
J
Rodríguez-Núñez
A
A
Pintos-Martínez
E
E
Benlloch-Marín
T
T
Barros-Angueira
F
F
D003062:Codon / Q000235:genetics; D018388:Codon, Terminator; D018450:Disease Progression; D005087:Glucan 1,4-alpha-Glucosidase / Q000172:deficiency / Q000235:genetics*; D006009:Glycogen Storage Disease Type II / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D006579:Heterozygote; D006801:Humans; D007223:Infant; D008297:Male; D009124:Muscle Proteins / Q000172:deficiency / Q000235:genetics; D018482:Muscle, Skeletal / Q000201:enzymology / Q000473:pathology; D010641:Phenotype; D017354:Point Mutation; D000520:alpha-Glucosidases
D003062:Codon; D018388:Codon, Terminator; D009124:Muscle Proteins; D000520:alpha-Glucosidases; D005087:Glucan 1,4-alpha-Glucosidase