Definition

The CYP11B1 gene encodes the mitochondrial enzyme 11beta-hydroxylase, which converts 11-deoxycortisol to cortisol in the zona fasciculata of the adrenal cortex. When the enzyme is deficient, cortisol synthesis is blocked and precursor steroids accumulate; this leads to both virilization due to androgen excess and salt retention and hypertension due to accumulation of precursors with mineralocorticoid activity, accounting for ~5-8% of classic CAH cases. Unlike 21-hydroxylase deficiency, hypertension rather than salt wasting is seen.

Gene/region examined

CYP11B1 - Exon 1, CYP11B1 - Exon 2, CYP11B1 - Exon 3, CYP11B1 - Exon 4, CYP11B1 - Exon 5, CYP11B1 - Exon 6, CYP11B1 - Exon 7, CYP11B1 - Exon 8, CYP11B1 - Exon 9

Method

Sequence analysis

Accepted sample types

EDTA blood, AF, CVS

Inheritance

Inherited, 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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