Definition

The INSR gene encodes the insulin receptor located in the cell membrane; biallelic variants cause severe insulin resistance (Donohue syndrome spectrum). Heterozygous variants can paradoxically cause both hyperinsulinemic hypoglycemia and insulin resistance; the clinical picture ranges widely from severe growth retardation in the newborn, loss of subcutaneous fat, acanthosis nigricans, organomegaly and hemihypertrophy to type 2 diabetes.

Gene/region analyzed

AKT2 - Exon 1, AKT2 - Exon 2, AKT2 - Exon 3, AKT2 - Exon 4, AKT2 - Exon 5, AKT2 - Exon 6, AKT2 - Exon 7, AKT2 - Exon 8, AKT2 - Exon 9, AKT2 - Exon 10, AKT2 - Exon 11, AKT2 - Exon 12, AKT2 - Exon 13, AKT2 - Exon 14

Method

Sequence analysis

Accepted sample types

EDTA blood, AF, CVS

Inheritance

Hereditary; severe forms show autosomal recessive (biallelic) inheritance, milder forms autosomal dominant/semi-dominant inheritance.

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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