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DHH gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

DHH gene

The DHH gene provides instructions for creating a protein involved in male-typical sex development and the formation of protective nerve membranes.

Normal Function

The DHH gene provides instructions for making a member of the hedgehog protein family. Hedgehog proteins are important for early development in many parts of the body. The protein produced from the DHH gene is believed to be involved in male-typical sex development and in the formation of the perineurium, the protective membrane around each bundle of fibers within a nerve.

Health Conditions Related to Genetic Changes

Swyer syndrome

DHH gene variants (also called mutations) have been identified in a small number of people with Swyer syndrome, also known as 46,XY complete gonadal dysgenesis or 46,XY pure gonadal dysgenesis. Swyer syndrome is a condition that affects sex development. Affected individuals have two altered copies of the DHH gene in each cell.

Sex development usually follows a particular pattern based on an individual's chromosomes. People usually have 46 chromosomes in each cell. Two of the 46 chromosomes, known as X and Y, are called sex chromosomes because they help determine whether a person will develop male or female sex characteristics. Girls and women typically have two X chromosomes (46,XX karyotype), and boys and men typically have one X chromosome and one Y chromosome (46,XY karyotype). However, individuals with Swyer syndrome have a male-typical chromosome pattern (46,XY karyotype), but they develop female-typical sex characteristics.

Variants in the DHH gene in people with Swyer syndrome affect the process of sex development, preventing affected individuals with a 46,XY karyotype from developing male gonads (testes) and causing them to develop female reproductive structures (a uterus and fallopian tubes).

Other disorders

DHH gene variants have been identified in people with 46,XY disorder of sex development, also known as partial gonadal dysgenesis. These individuals have one altered DHH gene in each cell. They may have external genitalia that do not look clearly male or clearly female or other changes in the genitals and reproductive organs.

Some people with the features of 46,XY disorder of sex development caused by DHH gene variants also have nerve abnormalities. This combination of features is a condition called 46,XY gonadal dysgenesis with minifascicular neuropathy. The nerve abnormalities affect nerves connecting the brain and spinal cord to muscles and sensory cells that detect sensations such as touch, pain, heat, and sound (the peripheral nervous system). Affected individuals may experience weakness and loss of sensation in their extremities (peripheral neuropathy).

Other Names for This Gene

  • desert hedgehog homolog (Drosophila)
  • DHH_HUMAN
  • HHG-3
  • MGC35145

Frequently Asked Questions

Swyer syndrome is a condition where individuals with a 46,XY karyotype (typically male) develop female physical characteristics. The DHH gene produces a protein essential for the development of testes. When both copies of the DHH gene are mutated, the testes fail to form properly during fetal development. Without functional testes, the body does not produce sufficient testosterone to drive male physical development, resulting in the formation of female reproductive structures and external genitalia.
Individuals with Swyer syndrome are typically infertile because they do not have functional ovaries or testes to produce eggs or sperm. However, they can become pregnant and carry a child to term using donor eggs and in vitro fertilization (IVF), as they possess a uterus and fallopian tubes. This option requires careful medical management to monitor for potential health risks associated with pregnancy in individuals with this condition.
The primary long-term health risk is an increased susceptibility to gonadal tumors, particularly germ cell tumors, in the undescended or dysgenetic gonadal tissue. Regular medical monitoring, including physical exams and imaging, is crucial to detect any abnormal growths early. Additionally, because these individuals develop as females, they require standard gynecological care and may need hormone replacement therapy to maintain bone density and overall health.
Diagnosis often begins with a discrepancy between an individual's physical sex characteristics and their chromosomal karyotype, which reveals a 46,XY pattern. Genetic testing, specifically sequencing of the DHH gene, can confirm the diagnosis by identifying pathogenic variants in both copies of the gene. This testing is important not only for confirming the cause of the condition but also for providing accurate genetic counseling to family members regarding inheritance patterns and potential risks for future pregnancies.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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