Branching enzyme deficiency: expanding the clinical spectrum.

Abstract

IMPORTANCE:

The neuromuscular presentation of glycogen branching enzyme deficiency includes a severe infantile form and a late-onset variant known as adult polyglucosan body disease. Herein, we describe 2 patients with adult acute onset of fluctuating neurological signs and brain magnetic resonance imaging lesions simulating multiple sclerosis. A better definition of this new clinical entity is needed to facilitate diagnosis.

OBJECTIVES:

To describe the clinical presentation and progression of a new intermediate variant of glycogen branching enzyme deficiency and to discuss genotype-phenotype correlations.

DESIGN, SETTING, AND PARTICIPANTS:

Clinical, biochemical, morphological, and molecular study of 2 patients followed up for 6 years and 8 years at academic medical centers. The participants were 2 patients of non-Ashkenazi descent with adult acute onset of neurological signs initially diagnosed as multiple sclerosis.

MAIN OUTCOMES AND MEASURES:

Clinical course, muscle and nerve morphology, longitudinal study of brain magnetic resonance imaging, and glycogen branching enzyme activity and GBE1 molecular analysis.

RESULTS:

Molecular analysis showed that one patient was homozygous (c.1544G>A) and the other patient was compound heterozygous (c.1544G>A and c.1961-1962delCA) for GBE1 mutations. Residual glycogen branching enzyme activity was 16% and 30% of normal in leukocytes. Both patients manifested acute episodes of transient neurological symptoms, and neurological impairment was mild at age 45 years and 53 years. Brain magnetic resonance imaging revealed nonprogressive white matter lesions and spinocerebellar atrophy similar to typical adult polyglucosan body disease.

CONCLUSIONS AND RELEVANCE:

GBE1 mutations can cause an early adult-onset relapsing-remitting form of polyglucosan body disease distinct from adult polyglucosan body disease in several ways, including younger age at onset, history of infantile liver involvement, and subacute and remitting course simulating multiple sclerosis. This should orient neurologists toward the correct diagnosis.

• Authors: Carmen Paradas, Hasan O Akman, Carolina Ionete, Heather Lau, Peter N Riskind, David E Jones, Thomas W Smith, Michio Hirano, Salvatore Dimauro
• Journal: JAMA neurology (JAMA Neurol) Vol. 71 Issue 1 Pg. 41-7 (Jan 2014) ISSN: 2168-6157 [Electronic] United States
• PMID: 24248152 (Publication Type: Case Reports, Journal Article, Multicenter Study, Research Support, Non-U.S. Gov't)

Chemical References

• Glycogen Debranching Enzyme System
• GBE1 protein, human

Topics

• Acute Disease
• Age of Onset
• Disease Progression
• Female
• Follow-Up Studies
• Genetic Carrier Screening
• Glycogen Debranching Enzyme System (genetics)
• Glycogen Storage Disease Type IV (enzymology, genetics, pathology)
• Homozygote
• Humans
• Leukoencephalopathies (diagnosis, genetics, pathology)
• Magnetic Resonance Imaging
• Male
• Middle Aged
• Spinocerebellar Ataxias (diagnosis, genetics, pathology)