Chapter 81 Turner Syndrome
PATHOPHYSIOLOGY
Turner syndrome is a genetic condition that occurs only in females, in which there is an X chromosome missing or abnormally structured. This results in short stature, ovarian dysgenesis, and infertility. It was first observed by Henry Turner in 1938, when he treated seven female patients for dwarfism and lack of sexual development. Through the years, the knowledge base about Turner syndrome has increased dramatically. Early treatments with pituitary extracts were ineffective; however, current treatments with growth hormone injections and other hormone therapies are creating much more positive outcomes for these girls.
The chromosomal abnormality occurs on chromosome 45. It can be a complete absence of X, a structural abnormality with partial deletion of X, or mosaicism, which is a mixture of the two. In mosaicism, some cells will have the typical 46 chromosomes and some will have 45. The gene has been identified at the SHOX or short stature homeobox–containing gene. Two copies of the SHOX gene are required for normal growth.
Girls with Turner syndrome may or may not be diagnosed in infancy. There may be a slight intrauterine growth restriction, and growth may be slow during infancy in early childhood.
There will be no pubertal growth spurt. Many body systems are affected by Turner syndrome, although not all girls with the syndrome will have all manifestations.
COMPLICATIONS
1. Cardiovascular: occurs in one of three girls, left-sided anomalies such as coarctation of the aorta and abnormalities of the aortic valve are the most common.
2. Neurologic: often have normal intelligence but may have difficulty with memory, attention, visual processing, and math. Psychosocial issues result from short stature and typical facial features that may cause teasing in school. Behavioral disorders may result from issues regarding self-esteem.
