Definition

The AFG3L2 gene encodes a zinc metalloprotease/ATPase responsible for quality control in the inner mitochondrial membrane. Heterozygous variants cause SCA28 and OPA12 (optic atrophy), while biallelic variants cause the more severe SPAX5 phenotype, presenting with early-onset spasticity, cerebellar ataxia, and myoclonic epilepsy.

Gene/region examined

AFG3L2 - Exon 1, AFG3L2 - Exon 2, AFG3L2 - Exon 3, AFG3L2 - Exon 4, AFG3L2 - Exon 5, AFG3L2 - Exon 6, AFG3L2 - Exon 7, AFG3L2 - Exon 8, AFG3L2 - Exon 9, AFG3L2 - Exon 10, AFG3L2 - Exon 11, AFG3L2 - Exon 12, AFG3L2 - Exon 13, AFG3L2 - Exon 14, AFG3L2 - Exon 15, AFG3L2 - Exon 16, AFG3L2 - Exon 17

Method

Sequence analysis

Accepted sample types

EDTA blood, AF, CVS

Inheritance

Inherited; SCA28/OPA12 autosomal dominant, SPAX5 autosomal recessive.

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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