Epidemiology

Turner syndrome occurs equally in all races and regions of the world. It is sporadic in occurrence except for rare cases in which a small X chromosome deletion may be passed from mother to daughter.

The number of females diagnosed prenatally may increase with increased use of noninvasive prenatal testing (NIPT).[6] Regardless, a postpartum karyotype is necessary to confirm the diagnosis.[3]​ Historically, less than 10% of cases are diagnosed prenatally; a further 20% are detected in infancy owing to the presence of lymphedema, neck webbing, or congenital heart defects. ​Relatively few patients are diagnosed during early childhood and they usually present with short stature. The largest proportion of detection is at ages 10 to 16 years, owing to a combination of marked short stature and delayed puberty. Another 10% are diagnosed in adulthood, owing to secondary amenorrhea. There are similar ascertainment profiles for the US and Europe.[7][8]

[Figure caption and citation for the preceding image starts]: Ascertainment profile data of Turner syndrome; 300 females; Age DX, age (in years) at diagnosisFrom the personal collection of Carolyn Bondy, MS, MD (National Institute of Child Health and Human Development natural history study 2001-2007; McCarthy K, et al. Expert Rev Endocrinol Metab. 2008;3:771-775) [Citation ends].com.bmj.content.model.Caption@4aba6c23

Whereas large-scale cytogenetic screening of newborns conducted in the 1970s and 1980s indicated a Turner syndrome incidence of about 1 case per 2000-2500 live female births,[9][10]​​ more recent surveys suggest a lower incidence of about 1 case per 5000 live female births due to prenatal diagnosis associated with terminations of pregnancies.[11]

Use of this content is subject to our disclaimer