Use of FSH in Early Diagnosis of Turner Syndrome

The testing and discovery of follicle stimulation hormone (FSH) levels above the normal range in young girls with unexplained short stature may lead to the early diagnosis of Turner syndrome, according to a study published in BMC Endocrine Disorders.

Researchers conducted a retrospective longitudinal study of 15 girls diagnosed with Turner syndrome during the first 5 years of life, and performed an analysis of FSH and luteinizing hormone (LH) levels taken routinely in these girls at follow-up visits (approximately every 6 months) since their diagnosis to evaluate whether a gonadotropin hormone pattern could be detected.

Study results found FSH levels overall to be abnormal in 93% and 80% of girls during early childhood and midchildhood, respectively. FSH level were abnormally high in 4 of 5 girls with gonadotropin hormone levels tested within the first 6 months of life. There were no normal prepubertal FSH levels found in 13 of 15 girls during early childhood, and at least 9 of the 13 had an FSH level in the postmenopausal range.

During midchildhood, 6 of 15 girls were found to have at least 1 normal FSH level; however, 3 of these girls had at least 1 postmenopausal FSH level, whereas only 1 girl had results consistently within the prepubertal normal range. Finally, girls >10 years of age without spontaneous pubertal development were found to have FSH levels that were only in the postmenopausal range.

An analysis of LH levels found normal prepubertal results in 62% and 82% of girls during early childhood and midchildhood, respectively. Of the 5 girls tested during the first 6 months of life, only 1 had an abnormally high level of LH, and the majority of girls had at least 1 normal LH level during early childhood and midchildhood.

A biphasic age pattern was observed with FSH levels in girls with Turner syndrome, as levels were high during the newborn/minipuberty and early childhood, and then declined during midchildhood without quite reaching normal prepubertal levels, followed by another rise in levels during late childhood/adolescence.

LH levels were also biphasic, as increased levels of LH were observed in late childhood/adolescence as well as the newborn/minipuberty period and early childhood; however, much higher abnormally high levels were noted in the late childhood/adolescence phase. The decline in LH during midchildhood was less drastic than seen in FSH levels, with prepubertal levels often seen during this time in LH, as opposed to FSH.

Researchers concluded that many girls could be diagnosed with Turner syndrome, and therefore begin to receive treatment specific for this disorder, if FSH levels were routinely checked in young girls with unexplained short stature, as many girls go undiagnosed until an average age of 12 years because of late primary care referral. Therefore, clinicians should consider including FSH as a part of their routine diagnostic evaluation of girls with unexplained short stature, as high FSH levels could prioritize early cytogenetic evaluation.

Reference

Carpini S, Carvalho AB, de Lemos-Marini SHV, Guerra-Junior G, Maciel-Guerra AT. FSH may be a useful tool to allow early diagnosis of Turner syndrome. BMC Endocr Disord. 2018;18:8.