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Jacobs syndrome

XYY syndrome is a aneuploidy of the sex chromosomes in which a human male receives an extra Y chromosome in each cell, hence having a karyotype of 47,XYY. XYY syndrome is also called Jacob's Syndrome, XYY-trisomy, 47,XYY aneuploidy, or Supermale syndrome. more...

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First case

The first published report of a man with a 47,XYY chromosome constitution was by Dr. Avery A. Sandberg, et al. of Buffalo, New York in 1961. It was an incidental finding in a normal 44-year-old, 6 ft. tall man of average intelligence.

Effects

Physical traits

XYY syndrome typically causes no unusual physical features or medical problems. Males with this syndrome may be slightly taller than average and are typically a few centimeters taller than their father and siblings.

Skeletal malformations may also accompany XYY syndrome at a higher rate than in the general population. Severe facial acne has occasionally been reported, but dermatologists specializing in acne (Plewig & Kligman, 2000) now doubt the existence of a relationship with XYY. Several other physical characteristics, including large hands and feet, have been associated (although not definitively) with XYY syndrome. Any physical characteristics, however, are usually so slight that they are insufficient evidence to suggest a diagnosis.

Most males with XYY syndrome have normal sexual development and are able to conceive children.

Since there are no distinct physical characteristics, the condition usually is only detected during genetic analysis for other reasons.

Behavioral characteristics

XYY boys have an increased risk of minor speech and motor skill delays and learning disabilities with roughly half requiring some special education intervention. Behavior problems are common but are not unique to XYY boys and managed no differently than XY boys.

Cause and prevalence

XYY syndrome is not inherited, but usually occurs as a random event during the formation of sperm cells. An error in cell division called nondisjunction can result in sperm cells with an extra copy of the Y chromosome. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have an extra Y chromosome in each of the body's cells. In some cases, the addition of an extra Y chromosome occurs as an accident during cell division in early fetal development.

The incidence of this condition is approximately one in 850 males.

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Preventing PMS: vitamin and mineral let women avoid syndrome
From Science News, 6/18/05 by B. Harder

Ample calcium and vitamin O in the diet prevent premenstrual syndrome in some women, a new study suggests.

Each month, as menstruation approaches and begins, most women experience at least mild symptoms such as depression, irritability, discomfort, or fatigue. In 8 to 20 percent of premenopausal women, these problems are severe enough to warrant a diagnosis of premenstrual syndrome, or PMS. That disorder is defined by symptoms that interfere with normal activities and relationships.

Studies have shown that calcium supplements, as well as antidepressant medications known as selective serotonin reuptake inhibitors (SN: 10/7/00, p. 231), can ease PMS.

No relationship was obvious between calcium consumption and risk of developing the disorder among women who don't have PMS, says epidemiologist Elizabeth R. Bertone-Johnson of the University of Massachusetts in Amherst.

To investigate the possibility of a link, she and her colleagues periodically contacted about 3,000 female nurses who in 1991 were free of PMS. They were, on average, 35 years old. Then, every 2 to 4 years, the researchers recorded how often each woman reported eating various foods and whether she had developed PMS. By 2001, 1,057 women reported having the disorder.

Volunteers who got the most calcium in their diets were only 70 percent as likely to develop PMS as were those who took in the least amount of the mineral. Variation in vitamin D consumption accounted for a similar difference, the researchers report in the June 13 Archives of Internal Medicine. Vitamin D helps the body absorb calcium.

The researchers also analyzed consumption of milk, which is rich in both nutrients. PMS was only 54 percent as likely to arise in women who had four or more daily servings of skim or low-fat milk as it was in women who drank milk no more than once a week, the researchers report. Whole milk offered no apparent benefit, perhaps because milk fats offset the nutrients' benefits, Bertone-Johnson says.

Too few of the volunteers took nutritional supplements containing calcium or vitamin D to show an effect from such pills, Bertone-Johnson says. But since calcium supplements can relieve PMS, pills containing either nutrient can probably prevent the condition too she says.

Most young women don't take supplemental calcium or vitamin D, but "maybe they should," says Susan Thys-Jacobs of St. Luke's-Roosevelt Hospital Center in New York City. "Women should be taking at least 1,000 milligrams of calcium and at least 1,000 units of vitamin D daily, and few get that much from diet alone," she says.

COPYRIGHT 2005 Science Service, Inc.
COPYRIGHT 2005 Gale Group

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