Definition

Heterozygous inactivating pathogenic variants in the GCK gene reduce the activity of glucokinase, the enzyme that acts as a glucose sensor in the pancreatic beta cell, resulting in mild, stable fasting hyperglycemia (GCK-MODY) that generally carries a low risk of complications. Rarely, biallelic inactivating variants lead to a much more severe permanent neonatal diabetes mellitus (PNDM).

Gene/region analyzed

GCK - Whole Gene

Method

Sequence analysis

Accepted sample types

EDTA blood, AF, CVS

Inheritance

Hereditary, autosomal dominant in the heterozygous form (GCK-MODY); autosomal recessive in the biallelic form (PNDM).

Related Tests

Inheritance Patterns

Describes how a genetic condition is passed on within a family. There are five main patterns

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Carrier (Heterozygous / Homozygous)

Why it matters: In autosomal recessive inheritance, when each parent is a carrier (while both appear healthy), the chance of their child being born with the disease is 25% in each

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VUS (Variant of Uncertain Significance)

This is the situation where the test has detected a change in the DNA, but the role of this change in the development of disease is unconfirmed.

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How to Read a Genetic Test Result (Positive / Negative / VUS)

A genetic test result falls into three main categories

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Types of Genetic Tests

A genetic test is a type of medical test that detects changes in genes, chromosomes or proteins. Today there are more than 77,000 genetic tests available.

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