Sietske N. Heyn is a medical writer with a PhD in neuroscience. Dr. Heyn's education includes a BS with honors from the University of Oregon, and a doctoral degree in neuroscience from the University of California at Davis. After completing postdoctoral training at the University of California, San Francisco, and many years of working as a medical writer at the Stanford University Center for Down Syndrome Research, Dr. Heyn now runs her own medical writing business.
Dr. Perlstein received his Medical Degree from the University of Cincinnati and then completed his internship and residency in pediatrics at The New York Hospital, Cornell medical Center in New York City. After serving an additional year as Chief Pediatric Resident, he worked as a private practitioner and then was appointed Director of Ambulatory Pediatrics at St. Barnabas Hospital in the Bronx.
The earliest known depiction of a person with Down syndrome is an angel in a
Flemish painting dated 1515. In 1866, Doctor John Langdon Down first described
Down syndrome as a disorder, but he misunderstood how Down syndrome arises. The
cause of Down syndrome was discovered rather recently in 1959.
Down syndrome is a genetic disorder and the most common cause of cognitive
impairment. All individuals with Down syndrome have mild to moderate
learning
disabilities, distinctive facial features, and low muscle tone (hypotonia) in
early infancy. Down syndrome is also often associated with heart defects,
leukemia, and early-onset
Alzheimer's disease. The degree to which an individual
is affected by these characteristics varies from mild to severe.
In the United States, about one baby in 800 live births has Down syndrome and
approximately 6000 children with Down syndrome are born in this country each
year. Due to recent advances in medical care and social inclusion, life
expectancy has increased dramatically for individuals with Down syndrome. About
85% of infants with Down syndrome survive 1 year, and 50% of people with Down
syndrome live longer than 50 years. The average life span is greater than 55
years.
Alzheimer's Disease in Down SyndromeAlzheimer's disease (AD) is the most common form of dementia (see Dementia Overview for more information). The disease is progressive, and the brain degenerates...learn more >>
Cognitive DeficitsCognitive deficits (intellectual disability) begin in childhood and cause impaired ability to learn and function. Impairment level is categorized as mild, moder...learn more >>
Characteristic Features and Symptoms of Down Syndrome
Despite the variability in Down syndrome, individuals with Down syndrome have a widely recognized characteristic appearance. Typical facial features include:
a flattened nose, small mouth, protruding tongue, small ears, and upward slanting eyes;
the inner corner of the eyes may have a rounded fold of skin (epicanthal fold);
the hands are short and broad with short fingers, and may have a single palmar crease;
white spots on the colored part of the eye called Brushfield spots may be present;
babies with Down syndrome often have decreased muscle tone at birth;
and
normal growth and development is usually delayed and often individuals with Down syndrome don't reach the average height or developmental milestones of unaffected individuals.
