Thyroid Dysfunction in the First Year of Life in Infants with Down syndrome: Linear Growth Over 4 Years

Nada Alaaraj; Ashraf Soliman; Maya Itani; Shayma Mohamed; Ahmed Khalil; ashraf adel

Background: Down syndrome (DS) is associated with thyroid dysfunction including both congenital and acquired hypothyroidism (HT) However, data about thyroid function in infants < 1 year with DS is scarce.

The aim of this study was to investigate the prevalence of different thyroid dysfunctions in a cohort of infants with DS (n = 47) (22 M, 25 F) and follow up their linear growth and weight gain for an average of 4 years.

Patients and Methods: Retrospectively we studied thyroid function in a cohort of infants with DS (n = 47) (below 1 year) and followed up their linear growth and weight gain (height SDS (HtSDS), delta HtSDS, BMISDS, and delta BMISDS) for an average of 4 years.

Results: presented in 2 tables

Table 1: Prevalence of thyroid dysfunction in infants with DS < 1 year of age
	Prevalence in DS
Number	47
Age, Mean (years)	0.5+/-0.3
Primary Hypothyroidism (low FT4 + high TSH)	1/47 (2%)
TSH > 15 mIU/L	5/47 (11%)
Central hypothyroidism	2/47 (4%)
TSH >5 and <15 mIU/L (subclinical hypothyroidism)	23/47 (49%)
TSH < 5 mIU/L	19/47 (40%)
Positive Anti Thyroid antibodies	9/47 (19%)
Other autoimmune disorders/antibodies	1/47 (2%)
Type 1 DM	1/47 (2%)
Congenital heart Disease (CHD)	36/47

Table 2: Growth of Children with DS categorized according to their primary thyroid function
Groups		age 1	LSD1	BMISDS1	age 2	LSD2	BMISDS2	Delta HTSDS	Delta BMISDS
TSH >5-<15	Mean	0.48	-1.46	-1.04	4.41	-1.99	0.43	-0.53	1.43
	SDS	0.38	1.28	1.38	4.25	0.81	1.14	1.16	1.63
TSH <5	Mean	0.54	-1.75	-0.99	2.54	-1.82	0.33	-0.07	1.32
	SDS	0.39	2.51	1.33	1.00	1.53	1.62	1.43	2.14
TSH >15	Mean	0.29	-2.43	-2.77*	4.46	-2.24	0.69	0.20	3.46*
	SDS	0.31	1.70	1.76	4.69	0.74	0.75	1.72	2.33
*P<0.05

Conclusion: Infants with DS < 1 year of age had a high prevalence of thyroid dysfunction. Subclinical HT (TSH > 5 and normal FT4) is the most frequent abnormality in these infants. Both primary and secondary HT are found in these infants. Autoimmunity against thyroid was detected in 19 % of these young infants (early autoimmunity). Infants with TSH > 15 had significantly lower BMISDS and were non-significantly shorter than the other groups (P= 0.03 and P =0.14 respectively). Infants with TSH> 15 mIU/L were treated with L thyroxine. After an average of 4 years of treatment, the BMISDS and HtSDS did not differ among the 3 groups.

ESPE Abstracts

P3-160