Down Syndrome
What Went Wrong?
Down syndrome is a genetic disorder resulting in retardation most commonly
caused by three instead of two chromosomes 21. Down syndrome can also be
caused by translocation of chromosome 21 where a portion breaks off and
attaches to another chromosome.
Abnormal chromosomes might occur because the mother is >34 years of
age or the father is >41 at the time of conception. It might also occur because
of a virus or radiation.
The degree of mental retardation varies. Some patients are fully dependent
on their caregivers. Other patients can function with little assistance.Signs and Symptoms
Broad flat forehead
Small oral cavity
Protruding tongue
Speckling of the irises (Brushfield spots)
Eyes slanting upward
Low-set ears
A single crease across the palm (simian crease)
Hypotonia
Mental retardation apparent in older infantsTest Results
Pregnancy-associated plasma protein A serum test (PAPP-A): Performed
during the first trimester to detect the level of plasma protein A that is
covering the fertilized egg. A low level is linked to Down syndrome.
Inhibit A serum test: Inhibit A inhibits the pituitary gland from produc-
ing the follicle-stimulating hormone (FSH) hormone. An increase level
of inhibit A is linked to Down syndrome.
Human chorionic gonadotropin (HCG) hormone serum test: The pla-
centa produces the human chorionic gonadotropin hormone, which is
used to determine pregnancy. An increase in the beta subunit of the
human chorionic gonadotropin hormone is linked to Down syndrome.
Alpha-fetoprotein (AFP) serum test: A decrease in alpha-fetoprotein is
linked to Down syndrome.
Amniocentesis: Identifies the chromosome abnormality and is per-
formed if the mother is >34 years of age or if the father carries a translo-
cated chromosome.Treatment
There is no cure for Down syndrome.
Provide occupational therapy to help the child master the skills of inde-
pendent living when possible.8CHAPTER 10/ Neurologic Conditions^219