Jolly et al
New Zealand Veterinary Journal 50(1), 2002
35
the exception of 1 pair of affected newborn twins (Gallen et al
1986), are not described in the perikaryon of neurons. However,
basophilic rounded inclusions occurred in neurons of Norwegian
forest cats with glycogenosis type IV (Fyfe et al 1992). These
appeared similar, although not identical, to those in the present
canine case. Ultrastructurally, the neuronal inclusions in this were
more coarsely granular than those in the liver and they appeared
both free within the cytoplasm (Figure 5) and also within
membranous organelles (Figure 6) that were interpreted to be
secondary lysosomes. As this disease does not otherwise resemble
Glycogen storage disease type II, a lysosomal storage disease due
to a deficiency of α-glucosidase, it is postulated that the
aggregations of abnormal polyglucan may have been taken into
the lysosomal system by autophagy. In the liver, the ultrastructure
of polyglucosan bodies was less fibrillar than the material in other
reports, but this could be due to inadequate fixation for electron
microscopy. Large polyglucosan bodies did not occur in the livers
of affected Norwegian forest cats. This was attributed to cats
normally having high hepatic gluconeogenic activity, storing little
hepatic glycogen and mobilising little hepatic glycogen when
fasted (Fyfe et al 1992).
examination of muscle, liver and even skin biopsies. At necropsy
of a suspected case, frozen tissues, as well as a full range of fixed
tissues including skin, should be kept for further biochemical
and histopathological investigation.
References
Bao Y, Kishnani P, WU J-J, Chen Y-T. Hepatic and neuromuscular forms of
glycogen storage disease type IV caused by mutations in the same glycogen-
branching enzyme. Journal of Clinical Investigation 97, 941–8, 1996
Cavanagh JB. Corpora-amylacea and the family of polyglucosan diseases. Brain
Research Reviews 29, 265–95, 1999
Chen YT, Burchell A. Glycogen storage diseases. In: Scriver CR, Beaudet AL,
Sly WS, Valle D (eds). The Metabolic and Molecular Bases of Inherited Disease,
7th Edition, Vol 1. Pp 935–65. McGraw-Hill, New York, 1995
Fyfe JC, Giger U, Van Winkle TJ, Haskins ME, Steinberg SA, Wang P, Patterson
DF. Glycogen storage disease type IV: Inherited deficiency of branching
enzyme activity in cats. Pediatric Research 32, 719–25, 1992
Gallen CC, Schultz P, Thomas CS, Jones M, Brown BI. Glycogenosis IV: Clinical
and pathological findings in siblings. Annals of Neurology 20, 404, 1986
Jian Z, Alley MR, Cayzer J, Swinney GR. Lafora’s disease in an epileptic Basset
hound. New Zealand Veterinary Journal 38, 75–9, 1970
Amylopectinosis, shown to be due to a deficiency of glycogen-
branching enzyme, has also been diagnosed in 3 Quarter horses,
a fetus, a neonate and a 1-month-old foal. There were prominent
large polyglucosan bodies in cardiac and skeletal muscle (Render
et al 1999). These were not noted in liver or brain but smaller
granules with similar staining characteristics did occur in these
tissues, being particularly abundant in motor neurons.Their small
size may reflect the very young age of these animals. Two further
cases of this disease in Quarter horse foals have been recorded
(Valberg et al 1998).
Lossos A, Meiner Z, Barash V, Soffer D, Schlesinger I, Abramsky O, Argov Z,
Shpitzen S, Meiner V. Adult polyglucosan body disease in Ashkenazi Jewish
patients carrying the Tyr329 Ser mutation in the glycogen-branching enzyme
gene. Annals of Neurology 44, 867–72, 1998
McKonkie-Rossell A, Wilson C, Picoli DA, Boyle J, DeClue T, Kishnani P,
Shen J-J, Boney A, Brown B, Chen YT. Clinical and laboratory findings in
four patients with non-progressive hepatic form of type IV glycogen storage
disease. Journal of Inherited Metabolic Disease 19, 51–8, 1996
Render JA, Common RS, Kennedy FA, Jones MZ, Fyfe JC. Amylopectinosis in
fetal and neonatal Quarter horses. Veterinary Pathology 36, 157– 60, 1999
Schochet SS, McCormick WF, Zellweger H. Type IV Glycogen storage disease
(amylopectinosis). Archives of Pathology 90, 354–63, 1970
The present report is the first putative diagnosis of Glycogen
storage disease type IV in dogs. Confirmation and full
characterisation of lesions must await further cases and
demonstration of a deficiency of glycogen-branching enzyme.
The history is relatively uninformative as to the primary breed
carrying this mutation. The dog was described as a Labrador-
cross by the owners, but the exact breeding was unknown. Given
the obvious rarity of the putative mutant gene, close consanguinity
would be expected in the immediate parentage so the mutation
could equally have come from another breed.
Schochet SS, McCormick WF, Korvasky J. Light and electron microscopy of
skeletal muscle in type IV glycogenosis. Acta Neuropathologica (Berlin) 19,
137–44, 1971
Summers BA, Cummings JF, de Lahunta A. Degenerative diseases of the central
nervous system, In: Veterinary Neuropathology. Pp 326–7. Mosby, St Louis,
1995
Valberg SJ, Hiraragi H, Ward TL, Rush B, Kinde H, Mickelson JR. Glycogen
branching enzyme deficiency: and emerging cause of neonatal mortality in
foals. Journal of Veterinary Internal Medicine 12, 234, 1998
Whereas the special enzymological tests to confirm a deficiency
of glycogen-branching enzyme may not be readily available to
practitioners, diagnosis may be aided by histopathological
Accepted for publication 27 September 2001