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Macrozoospermia
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Macrozoospermia

Macrozoospermia is a rare male infertility disorder characterized by abnormally large, polyploid sperm heads and multiple flagella, caused by mutations in the AURKC gene.

Overview

Macrozoospermia is a condition that affects only males. It is characterized by abnormal sperm and leads to an inability to father biological children (infertility). In affected males, almost all sperm cells have abnormally large and misshapen heads. The head of the sperm cell contains the male's genetic information that is to be passed on to the next generation. Normally, the head of a sperm cell contains . In men with macrozoospermia, the sperm cell head contains extra chromosomes, usually four copies of each instead of the usual one. This additional genetic material accounts for the larger head size of the sperm cell. Additionally, instead of having one tail (flagellum) per sperm cell, affected sperm have multiple flagella, most often four.

Because of the additional genetic material, if one of these abnormal sperm cells combines with an egg cell, the embryo will not develop or the pregnancy will result in miscarriage.

Frequency

Macrozoospermia is estimated to affect 1 in 10,000 males in North Africa. The prevalence of the condition outside this region is unknown.

Causes

Mutations in the AURKC gene cause macrozoospermia. The AURKC gene provides instructions for making a protein called aurora kinase C. This protein is abundant in male testes, which are the male reproductive organs in which sperm are produced and stored. In the testes, this protein regulates the division of sperm cells. Aurora kinase C ensures that the mechanisms for cell division are in place and helps chromosomes properly align with each other so that every new sperm cell contains after cell division.

AURKC gene mutations that cause macrozoospermia lead to the production of a nonfunctional protein or a protein that is quickly broken down. This lack of aurora kinase C blocks cell division in sperm cells. Without cell division, the chromosomes are not split among multiple new sperm cells. As a result, affected sperm cells contain extra chromosomes, usually four copies of each instead of the usual one.

Learn more about the gene associated with Macrozoospermia

  • AURKC

Inheritance

This condition is inherited in an , which means both copies of the gene in each cell have mutations. The parents of an individual with

Frequently Asked Questions

URKC mutations are inherited in an autosomal recessive manner. Both partners must carry a pathogenic variant for a child to be affected. If only the male partner is affected, his children will be carriers but will not develop macrozoospermia unless the mother also carries a pathogenic variant. Carrier testing of the female partner and genetic counseling are recommended before attempting conception.
t present, no pharmacologic treatment can correct the underlying AURKC defect or normalize sperm morphology. Management focuses on using the patient’s own sperm for ICSI after thorough morphological selection, or, in rare cases, retrieving donor sperm if the couple prefers to avoid genetic testing of embryos.
standard semen analysis will reveal a high percentage (>80 %) of sperm with abnormally large, polyploid heads and often multiple flagella. Flow cytometry or fluorescence in‑situ hybridization (FISH) can confirm increased chromosome numbers (tetraploidy). Electron microscopy may be used for detailed morphology, and genetic testing for AURKC mutations provides a molecular diagnosis.
Yes, intracytoplasmic sperm injection (ICSI) combined with pre‑implantation genetic testing for aneuploidy (PGT‑A) is the current standard. Because most macrozoospermic sperm carry extra chromosomes, selecting a morphologically normal sperm and testing embryos for chromosomal balance dramatically improves pregnancy rates and reduces miscarriage risk.
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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