Exam 3: Fragile X, Klinefelter and Turner Syndrome Flashcards
Is fragile x syndrome inherited or random?
Fragile X is an inherited disorder
It is second to DS in intellectual development disorders (IDD)
What is fragile x syndrome?
Named because of a fragile site or break in the X chromosome
What is the average age of diagnosis of fragile X?
36-42 months
Affects males and females
What are clinical manifestations of fragile x?
Long and protruding ears Long, thin face with prominent jaw Epicanthal folds High-arched palate Increased head circumference Large testes
What are behavioral manifestations of fragile x?
Mild to severe IDD
Speech defects
Attention deficits
Autistic-like behaviors
What is management of fragile x?
No cure
Managing symptoms, especially behavior-disorder symptoms
Pharmacolgic treatment: Ritalin, Dexedrine, Clonidine
Interdisciplinary treatment; team approach
Genetic evaluation of relatives, especially anyone with a family history of IDD with no diagnosis
What is Klinefelter syndrome?
Males are born with an extra copy of the x chromosome
Males with Klinefelter syndrome have 47 chromosomes.
Genetic analysis shows XXY instead of XY.
Majority of cases have 47, the XXY constitution.
Variants are rare and include 48 (XXXY) or 49 (XXXXY) chromosomes.
T or F: Older mothers are more at risk to have a child with Klinefelter syndrome than younger mothers?
True; often born to older mothers
What is Turner syndrome?
Women with only one X chromosome.
Missing genetic material affects development before and after birth.
Complete loss of one X chromosome in about 50% of patients.
Sometimes chromosomal changes in only some cells.
Usually not inherited.
Error in cell division; similar to nondisjunction in Down syndrome.
Does Klinefelter syndrome affect males or females or both?
Klinefelter affects males only
Does Turner syndrome affect males or females or both?
Turner affects females only
What is the most common sex chromosome abnormality?
XXY-Klinefelter syndrome
When are men with Klinefelter syndrome typically diagnosed?
Puberty
-failure of adolescent secondary sex characteristic development
What is seen with Klinefelter syndrome?
- microorchidism/small testes
- sterility/lack of sperm
- normal to borderline IQ
- diminished facial hair
- lack libido or sex drive
What is important for PCPs to do when caring for a child with family history of intellectual disabilities of unknown etiology?
-do a genetic evaluation of the relatives
In Klinefelter syndrome, physical and mental abnormalities associated with the syndrome increase as the number of ….
sex chromosomes increases: the more X chromosomes, the more symptoms
With Turner syndrome, you would see a complete loss of X chromosome in about ____ percentage of cases:
50%
What is it called when there are only chromosomal changes in some cells and not all?
Mosaicism
Is Turner syndrome inherited?
Not usually
Frequency of Turner Syndrome:
1 in 2500
Frequency of Klinefelter Syndrome:
1 in 500 to 1 in 1,000
Turner syndrome is a common cause of what?
Miscarriages
Turner syndrome in newborns characteristics:
- webbing of neck
- lymphedema in hands and feet
- 1/3 to 1/2 with heart defect
Cardiac abnormalities seen in Turner Syndrome:
- Aortic valve abnormality
- Coarctation of aorta
What is the most common feature of Turner syndrome?
Short stature
Characteristics of Turner Syndrome:
- Short stature
- loss of ovarian function (ovaries develop normally, egg cells die prematurely)
- require hormone therapy to undergo puberty
- most are infertile with the exception of a small percentage that can retain normal ovarian function through young adulthood
Causes of short stature in Turner Syndrome:
Scoliosis & Kyphosis
Women with Turner syndrome have an increased risk for this as they age:
Osteopenia, Osteoporosis
What are approved treatments for Turner Syndrome?
- Growth hormone
- Estrogen replacement therapy starting at age 12
IQ score in Fragile X:
30 to 55
