Scientists identify new gene responsible for puberty disorders

Oct 27, 2008
A new gene responsible for some puberty disorders has been identified by Medical College of Georgia researchers. They found that the gene mutated in CHARGE syndrome -- a multi-system disorder characterized by diverse problems from heart defects to hearing loss to cleft lip and palate and mental retardation - also accounts for about 6 percent of two puberty disorders -- idiopathic hypogonadotropic hypogonadism, or IHH, and Kallmann syndrome. Credit: Medical College of Georgia

A new gene responsible for some puberty disorders has been identified by Medical College of Georgia researchers.

They found that the gene mutated in CHARGE syndrome – a multi-system disorder characterized by diverse problems from heart defects to hearing loss to cleft lip and palate and mental retardation – also accounts for about 6 percent of two puberty disorders. These disorders – idiopathic hypogonadotropic hypogonadism, or IHH, and Kallmann syndrome – short circuit puberty and can cause infertility. Kallmann syndrome is also marked by patients' inability to smell.

Dr. Lawrence Layman, chief of the MCG Section of Reproductive Endocrinology, Infertility and Genetics in the School of Medicine, and colleagues published an article in the October issue of The American Journal of Human Genetics linking the diseases.

CHARGE syndrome can also impair the sense of smell and inhibit production of sex steroids and hormones, so researchers suspected a common gene.

"Thinking that IHH and Kallmann syndrome could represent a milder version of CHARGE Syndrome, we set out to study the gene in a large sample of patients diagnosed with delayed puberty but not CHARGE," Dr. Layman says.

The identified gene is called chromodomain helicase DNA binding protein 7, or CHD7. In 101 people with IHH and Kallmann syndrome, researchers found seven mutations of CHD7 that weren't present in nearly 200 healthy individuals.

"This suggests that they were mutations causing the disorder, and we also showed that most of these mutations impaired the gene's function," Dr. Layman says.

Typically, puberty begins around age 10 in boys and age 8 or 9 in girls. It starts when the hypothalamus in the brain releases more gonadotropin releasing hormone, or GnRH, which stimulates the pituitary gland to make puberty-related hormones. This prompts ovaries to produce estrogen and eggs and testes to produce testosterone and sperm.

Pubertal disorders, Dr. Layman says, often begin long before that chain of events begins.

He traces the defects to gestation, when neurons linked to reproduction and sense of smell fail to reach their destination together.

"While the discovery of additional genes involved in pubertal disorders is significant, we only know the cause for about one-third of all affected patients," says Hyung-Goo Kim, molecular geneticist in the Institute of Molecular Medicine and Genetics and the study's first author. "We know now that CHD7, only the second gene identified as a cause for IHH and Kallmann Syndrome, is a common culprit."

"There is still work to be done," says Dr. Layman, corresponding author. "But this work is important because it gives us cause for genetic counseling on patients with these mutations. And because these findings suggest that IHH and Kallmann Syndrome are mild variants of CHARGE, it also prompts us to look more carefully for heart problems, hearing loss and cleft lip/palate in patients with pubertal abnormalities."

Source: Medical College of Georgia

Explore further: Researchers find new mechanism for neurodegeneration

add to favorites email to friend print save as pdf

Related Stories

Hoverbike drone project for air transport takes off

4 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

5 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 ...

'Shocking' underground water loss in US drought

5 hours ago

A major drought across the western United States has sapped underground water resources, posing a greater threat to the water supply than previously understood, scientists said Thursday.

Recommended for you

Researchers find new mechanism for neurodegeneration

7 hours ago

A research team led by Jackson Laboratory Professor and Howard Hughes Investigator Susan Ackerman, Ph.D., have pinpointed a surprising mechanism behind neurodegeneration in mice, one that involves a defect in a key component ...

Schizophrenia's genetic architecture revealed (w/ Video)

Jul 23, 2014

Queensland scientists are closer to effective treatments for schizophrenia after uncovering dozens of sites across the human genome that are strongly associated with a genetic predisposition to schizophrenia.

Mysterious esophagus disease is autoimmune after all

Jul 22, 2014

(Medical Xpress)—Achalasia is a rare disease – it affects 1 in 100,000 people – characterized by a loss of nerve cells in the esophageal wall. While its cause remains unknown, a new study by a team of researchers at ...

User comments : 0