Why is Apert's syndrome so common when mutation rate is so low?

Aug 28, 2007

Aperts syndrome is a condition caused by a mutation that produces fused fingers and toes, and alters cranial development in affected children. It arises spontaneously, but why the mutation that causes this syndrome appears so frequently has been a mystery.

In a new study published this week in the open-access journal PLoS Biology, Jian Qin, Norman Arnheim, and colleagues from University of Southern California provide compelling evidence that suggests the syndrome is perpetuated because the cells carrying the mutation in the testes, and that give rise to sperm, out-replicate normal cells.

The researchers have shown that the single base-pair mutation responsible for over 60% of Aperts cases occurs with such high frequency not because the relevant gene sits at a “mutation hotspot,” but because mutant cells reproduce more frequently then normal cells.

The Aperts mutation occurs in cells with a frequency between 100 and a 1000 times higher than would be predicted given a standard mutation rate. The researchers have developed a new experimental approach that measures the anatomical distribution of the mutant cells in order to investigate the mutation’s origin. They dissected healthy testes to map where the mutations had arisen, and found that mutant cells were clustered together. This distribution cannot be explained by the “hotspot” model, which would place the mutant cells randomly throughout the organ.

Instead, this paper shows that clustered mutations arise because cells carrying the genetic change out-compete normal testes cells and tend to accumulate, producing more sperm that carry the mutation and a higher frequency of transmission.

Source: Public Library of Science

Explore further: Smartphone experiment tracks whether our life story is written in our gut bacteria

add to favorites email to friend print save as pdf

Related Stories

Hoverbike drone project for air transport takes off

10 hours ago

What happens when you cross a helicopter with a motorbike? The crew at Malloy Aeronautics has been focused on a viable answer and has launched a crowdfunding campaign to support its Hoverbike project, "The ...

Study indicates large raptors in Africa used for bushmeat

11 hours ago

Bushmeat, the use of native animal species for food or commercial food sale, has been heavily documented to be a significant factor in the decline of many species of primates and other mammals. However, a new study indicates ...

Recommended for you

Monitoring the rise and fall of the microbiome

4 hours ago

Trillions of bacteria live in each person's digestive tract. Scientists believe that some of these bacteria help digest food and stave off harmful infections, but their role in human health is not well understood.

Antioxidant biomaterial promotes healing

12 hours ago

When a foreign material like a medical device or surgical implant is put inside the human body, the body always responds. According to Northwestern University's Guillermo Ameer, most of the time, that response can be negative ...

Immune response may cause harm in brain injuries, disorders

14 hours ago

Could the body's own immune system play a role in memory impairment and cognitive dysfunction associated with conditions like chronic epilepsy, Alzheimer's dementia and concussions? Cleveland Clinic researchers believe so, ...

User comments : 0