AAV Vectors Encoding Modified G6Pase-α for GSD-Ia Deficiency

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Solution Overview

Problem

Current gene therapy approaches using recombinant adeno-associated virus (AAV) vectors have not been able to completely correct hepatic glucose-6-phosphatase-α (G6Pase-α) deficiency in glycogen storage disease type Ia (GSD-Ia), leading to chronic complications such as hepatocellular adenoma and hepatocellular carcinoma.

Innovation Solution

Development of AAV vectors encoding modified human G6Pase-α enzymes with increased activity, achieved by introducing specific amino acid substitutions, such as serine to cysteine at position 298, and optimized codon usage, to enhance enzyme function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If standard AAV vectors encoding wild-type human G6Pase-α are used for gene therapy, then the therapy can be administered to patients with GSD-Ia, but the enzyme activity is insufficient to completely correct hepatic G6Pase-α deficiency

Engineering Contradiction:

Improveefficacy of gene therapyVSAvoidenzyme activity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies parameter changes by modifying the amino acid sequence of the G6Pase-α enzyme through site-directed mutagenesis. Specific residues are mutated to match the corresponding canine G6Pase-α sequence, which has higher enzymatic activity. This changes the biochemical parameters of the enzyme to achieve superior therapeutic efficacy while maintaining compatibility with the AAV vector delivery system.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If amino acid substitutions are introduced to increase enzyme activity, then enzyme function is enhanced, but the complexity of vector design and manufacturing increases

Engineering Contradiction:

Improveenzyme activityVSAvoidvector design complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies local quality by introducing specific point mutations at defined positions in the G6Pase-α protein sequence rather than attempting global optimization. Only selected amino acid residues are modified to match the canine sequence, allowing localized improvements in enzyme activity while maintaining the overall protein structure and simplifying the mutagenesis strategy.

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The modified G6Pase-α enzymes effectively correct hepatic G6Pase-α deficiency, improving glucose homeostasis, preventing hypoglycemia, and reducing the risk of hepatocellular adenoma and hepatocellular carcinoma in GSD-Ia patients.

Implementation Method 1

This enzyme catalyzes the hydrolysis of glucose-6-phosphate (G6P) to glucose and phosphate in the terminal step of glycogenolysis and gluconeogenesis

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Data Source

PatentUS12440580B2Adeno-associated virus vectors encoding modified G6PC and uses thereof

Publication Date: 2025.10.14 THE GOVERNMENT OF THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY DEPARTMENT OF HEALTH & HUMAN SERVICES

AI summary

Modified G6PC (glucose-6-phosphatase, catalytic subunit) nucleic acids and glucose-6-phosphatase-α (G6Pase-α) enzymes with increased phosphohydrolase activity are described. Also described are vectors, such as adeno-associated virus (AAV) vectors, and recombinant AAV expressing modified G6Pase-α. The disclosed AAV vectors and rAAV can be used for gene therapy applications in the treatment of glycogen storage disease, particularly glycogen storage disease type Ia (GSD-Ia), and complications thereof.