Definition

The microdeletion in the 17p13.3 region spans the PAFAH1B1 (LIS1) gene, associated with lissencephaly, and usually the adjacent YWHAE gene; in addition to classic lissencephaly, it leads to Miller-Dieker syndrome, characterized by a typical facial appearance, severe intellectual-motor disability, epilepsy, and growth retardation. Its incidence is approximately 1/100,000 births.

Method

FISH analysis

Accepted sample types

Amniotic fluid, Chorionic villus, Cord blood

Inheritance

Most cases are de novo; rarely results from a balanced translocation carried by a parent.

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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