Final height and pubertal growth in Japanese patients with congenital hypothyroidism detected by neonatal screening.

Abstract

To investigate the final adult heights and pubertal growth patterns in Japanese patients with congenital hypothyroidism (CH) detected by neonatal screening. A retrospective chart review was conducted of female patients >15 y of age (n = 18) and male patients >18 y of age (n = 9), who were detected by neonatal screening and kept on continuous thyroid hormone replacement therapy. Final height standard deviation scores (FHSDS) and target height standard deviation scores (THSDS) were determined. Parameters characterizing the pubertal growth process (such as age at onset of pubertal growth spurt and age at peak pubertal growth) were obtained from each patient's growth rate chart. Menarchial age was determined in each female patient by reviewing the medical record. The impact on FHSDS of the etiology of CH, the severity of CH, the time of initiation of therapy and the adequacy of treatment during the first year of life was assessed. All patients had received initial thyroid hormone treatment no later than 50 d of age, and had reached their final height. The mean FHSDS for female and male patients were +0.17 +/- 0.99 and -0.03 +/- 0.99, respectively. The mean FHSDS-THSDS for female and male patients was +0.09 +/- 0.77 and -0.19 +/- 0.53, respectively. No difference was seen in pubertal growth parameters for either gender compared with that of the reference population, except for a greater peak height velocity and pubertal height gain in male patients. The mean menarchial age was identical to that of the reference population. No significant relationship was found between the FHSDS and any of the factors investigated. The adult height of patients with CH detected by neonatal screening was equivalent to that of the reference population and their target height. As long as early intervention and satisfactory management are ensured, severe CH does not appear to reduce final adult height.