Etiological evaluation of primary congenital hypothyroidism cases

Abstract

Aim: Primary congenital hypothyroidism is frequently seen endocrine disorder and one of the preventable cause of mental retardation. Aim of study was to evaluate the frequency of permanent/transient hypothyrodism, and to detect underlying reason to identfy any marker which carries potential to discriminate permanent/transient form. Material and Methods:Forty eight cases older than 3 years of age, diagnosed as primary congenital hypothyroidism and started thyroxin therapy in newborn-period, and followed up between January 2007-June 2013 were included in the study. Thyroid hormon levels were evaluated and thyroid ultrasonography was performed in cases who are at the end of their 3 years of age, after 6 weeks of thyroxine free period. Thyroid sintigraphy was performed if serum thyroid-stimulating hormone was high (≥ 5 mIU/mL) and perchlorate discharge test was performed if uptake was normal or increased on sintigraphy. Cases with thyroid-stimulating hormone levels ≥ 5 mIU/mL were defined as permanent primary congenital hypothyroidism group and as transient primary congenital hypothyroidism group with normal thyroid hormones during 6 months. Results:The mean age was 3.8±0.7 years. Mean diagnosis age was 16.6±6.5 days and 14 cases (29.2%) were diagnosed by screening program of Ministry of Health. There were 23 cases (14F, 9M) in permanent primary congenital hypothyroidism group and 12 (52.2%) of them were dysgenesis (8 hypoplasia, 4 ectopia), and 11 (47.8%) dyshormonogenesis. In transient primary congenital hypothyroidism group, there were 25 cases (17M, 8F). The mean thyroid-stimulating hormone levels at diagnosis were similar in two groups. The mean thyroxin dose in permanent primary congenital hypothyroidism group was significantly higher than transient group at the time of thyroxin cessation (2.1±0.7, 1.5±0.5 mg/ kg/d, respectively, p=0.004). Thyroxin dose ≥1.6 mcg/kg/d was 72% sensitive and 69.6% specific for predicting permenant primary congenital hypothyroidism. Conclusions:Transient primary congenital hypothyroidism is more frequent than expected and found often in males in the primary congenital hypothyroidism cases, started thyroxin therapy in neonatal period. While fT4, thyroid-stimulating hormone, Tg levels at diagnosis do not predict transient/permenant primary congenital hypothyroidism, thyroxin dose before the therapy cessation at the age of 3 may make the distinction between transient/permenant primary congenital hypothyroidism. (Turk Pediatri Ars 2017; 52: 85-91)

Etiological Evaluation of Congenital Hypothyroidism in Cases Referred from the National Screening Program

“…In many studies, it has been reported that CH is more common in girls (13,14). However, in recent studies, male dominance has been reported, similar to our study (15)(16)(17). Since dysgenesis is known to be more frequent in girls and the rate of dysgenesis is relatively low in our study, it was thought that the higher frequency of males could be related to reasons other than dysgenesis.…”

Cases Referred from the Turkish National Screening Program: Frequency of Congenital Hypothyroidism and Etiological Distribution

“…Özgelen et al (13) reported that the rate of dysgenesis was found to be 83.7% of the patients with CH (51.7% hypoplasia, 21.7% agenesis, 10.3% ectopia) and rate of dyshormonogenesis was found to be 10.3% in patients; etiological distribution in this study was made only among the cases with permanent CH and both USG and scintigraphy were used for etiological evaluation. Similarly, in the study of Bezen et al (19), etiological distribution was evaluated among the cases with permanent CH; rate of dysgenesis was found to be 52.2% (34.8% hypoplasia, 17.4% ectopia) and rate of dyshormonogenesis was found to be 47.8% in patients. Although there are many studies which have reported that the rate of dysgenesis is high (20,21), there has been an increase in the rate of dyshormonegenesis in recent studies in accord with our findings (19,22).…”

“…Similarly, in the study of Bezen et al (19), etiological distribution was evaluated among the cases with permanent CH; rate of dysgenesis was found to be 52.2% (34.8% hypoplasia, 17.4% ectopia) and rate of dyshormonogenesis was found to be 47.8% in patients. Although there are many studies which have reported that the rate of dysgenesis is high (20,21), there has been an increase in the rate of dyshormonegenesis in recent studies in accord with our findings (19,22). An Italian national study conducted by Olivieri et al (12) reported the rate of dysgenesis in CH cases was 82% between years 1987 and 1998 although it decreased significantly compared to the previous period with a rate of 58% between years 1999 and 2006 due to significant chnages in the screening protocols used in Italy and, the authors speculate, the increased survival of many more premature infants.…”

Spatial Distribution of Congenital Hypothyroidism

“…1,33 Using iodine solvents in neonatal navel care and post-surgery operation care in mothers are still ongoing in both cesarean and normal delivery. 40 Some recent reports indicate iodine deficiency in parts of Iran. 41 A national study also demonstrated iodine deficiency in pregnant women, despite sufficiency in the iodine status of the total population.…”