Turner Syndrome and GrowthHeather J. McKnight, MSN, CRNP

Short stature, while not in itself a medical condition, should alert health care providers to the possibility

of a syndrome or chronic condition (Lipman & McKnight, 2000). Short stature is often overlooked,considered to be untreatable or, simply insignificant. The reality is, short stature is often treatable, even

if it is a component of chronic illness or a syndrome.

Short stature is a primary characteristic of Turner Syndrome. Turner Syndrome (TS) is a condition

manifested in females who have only one X chromosome or a closely linked mosaic pattern ofkaryotype. Girls with TS have dysgenetic ovaries and will most likely be infertile. Characteristics of TS

include lack of sexual maturation, webbed neck, and a wide carrying angle. A karyotype should be

performed on any female child with poor growth to rule out TS.

Poor growth has been identified in 95% of girls with TS (Rosenfeld et al., 1998). This growth failure

may not achieve recognition, especially if the patient has a mosaic form of TS. Mosaic forms of TS lead

to less noticeable manifestations of TS characteristics. A low birth weight and length may be overlooked

if the syndrome has not yet been identified. Growth velocity tends to coincide with that of unaffectedpeers during the first 3 years of life. Girls with TS tend to demonstrate gradual growth failure compared

with unaffected peers until about the age of 9 years. Age 9 appears to be when the 95th percentile of the

TS growth chart and the 5th percentile of the standard 2-18 year female growth chart begin to separate(Neely & Rosenfeld, 1996).

Growth hormone secretion in females with TS has been studied. Provocative growth hormone testing in

children with TS reveals normal growth hormone levels (Ross, Long, Loriaux & Cutler, 1985). Growth

hormone testing in adolescents shows a decrease in growth hormone along with a corresponding declinein insulin-like growth factor (IGF-1) (Cuttler, Van Vliet, Conte, Kaplan & Grumbach, 1985). It has been

hypothesized that girls with TS demonstrate declining levels of growth hormone and IGF-1 during

adolescence because they lack the estrogen stimulation. The documented short statue in childhoodsuggests that growth failure in TS is not endocrine in origin but rather an intrinsic bone defect since

growth hormone levels are not deficient in childhood (Neeley & Rosenfeld, 1996).

Despite the lack of proven growth hormone deficiency in children with TS, growth hormone started

during childhood has been demonstrated to make a difference in adult height of women with TS(Plotnick, Attie, Blethen & Sy, 1998). Females with TS are generally 20 cm shorter than their unaffected

peers (Ranke & Grauer, 1994). Retrospective data from the National Cooperative Growth Study

(NCGS) experience as reported by Plotnick et al. (1998) reveals growth rates increased from 4.0+ 2.3cm/yr before growth hormone to 7.5+2.0 cm/yr after 1 year of treatment. Data on final height present by

Plotnick et al. (1998) strongly demonstrate the benefit of growth hormone for girls with TS despite their

lack of growth hormone deficiency.

Growth hormone has been approved for use in girls with Turner Syndrome. The best results of growthhormone treatment in girls with TS have been found if growth hormone therapy is initiated at age 6-7

years (Castigila, 1997). It is therefore imperative that females with TS be identified as promptly as

possible so they may achieve the maximum benefits of growth hormone therapy. Any female with short

stature must alert health care providers to the possibility of Turners Syndrome.

References

Castiglia, P. T. (1997). Turner syndrome. Journal of Pediatric Health Care, 11(1), 34-36.

Cuttler, L., Van Viliet, G., Conte, F. A., Kaplan, S. L., & Grumbach, M. M. (1985). Somatomedin-C

levels in children and adolescents with gonadal dysgenesis: Differences from age-matched normal

females and effect of chronic estrogen replacement therapy. Journal of Clinical Endocrinology andMetabolism, 60,1087-1092.

 

Lipman, T. H. & McKnight, H. J. Children with chronic conditions: The importance of growthassessment. (in press). Nurse Practitioner Forum.

Neeley, E. K., & Rosenfeld, R. G. (1996). Turner syndrome. In F. Lifshitz (ed.), Pediatric

Endocrinology (pp. 267-280). New York: Marcel Dekker Inc.

Plotnick, L., Attie, K. M., Blethen, S. L., & Sy, J. P. (1998). Growth hormone treatment of girls withTurner syndrome: The national cooperative growth study experience. Pediatrics, 102, 479-481.

Rosenfeld, R. G., Frane, J., Attie, K. M., Brasel, J. Burstein, S. Cara, J. F., Chernausek, S., Gotlin, R.

W., Kuntze, J., Lippe, B. M., Mahoney, P. C., Moore, W. V., Saenger P., & Johanson, A. J. (1992). Six-

year results of a randomized prospective trail of human growth hormone and oxandrolone in Turnersyndrome. The Journal of Pediatrics, 121(1), 49-55.

Ross, L. J., Long, L, M, Loriaux, D. L. & Cutler, G. B. Growth hormone secretory dynamics in Turner

syndrome. The Journal of Pediatrics, 106 (2), 202-206.