vitamin-b-12 and Congenital-Hypothyroidism

In this study we evaluated whether vitamin B12 deficiency affects neonatal screening (NS) for congenital hypothyroidism (CH).. A cross-sectional study conducted from 2010 to 2011. A total of 10,740 infants were born in our hospital in this period. Thyroid-stimulating hormone (TSH) was tested for NS and neonates with abnormal screening results (TSH>20 mIU/L) were re-examined. Two hundred and twenty-nine re-called subjects (re-call rate 2.3%) were compared to 77 randomly selected newborns with normal TSH screening among these term newborns in terms of serum TSH, free T4, vitamin B12 and homocysteine status.. Of the 229 re-called subjects, 11 infants with CH and 21 infants with transient TSH elevation were detected. In the normal TSH screening group, only two infants were diagnosed with transient TSH elevation. Mean serum B12 levels were 126.4±48.7 pg/mL and 211.9±127.9 pg/mL in the positive TSH-screening group and the control group, respectively. There was a significant difference between positive and normal TSH-screening groups in regard to serum TSH, free T4, serum B12 and homocysteine levels.. We found a significant vitamin B12 deficiency in positive TSH-screening infants. Beside the crucial role of vitamin B12 in newborns, deficiency seems to increase the recall rates of infants in an NS program for CH.

Topics: Case-Control Studies; Congenital Hypothyroidism; Cross-Sectional Studies; Female; Humans; Infant, Newborn; Male; Neonatal Screening; Thyroid Function Tests; Thyrotropin; Vitamin B 12; Vitamin B 12 Deficiency

S-Adenosylhomocysteine (SAH) is the metabolic precursor of all the homocysteine (Hcy) produced in the body. It is formed by the enzyme SAH hydrolase in a reversible reaction. In a previous study we have shown that plasma SAH is a more sensitive indicator of the risk for cardiovascular disease, and in a second study involving patients with renal disease, we also showed that it is a more sensitive indicator of renal insufficiency than plasma Hcy. However, in the latter study, the patients with renal disease were older and had a variety of other diseases such as diabetes and primary hypertension, which are associated with vascular disease and which could reduce renal function by involvement of the kidneys. Our objective was to rule out these complicating factors as the cause of the elevated SAH in renal disease and determine whether renal insufficiency alone was the cause of the elevated SAH. We therefore measured SAH, Hcy, folate, and vitamin B12 in 23 patients between the ages of 1 and 18 years with a wide range of renal function, but who had none of these complicating factors. Glomerular filtration rate (GFR) was calculated using serum creatinine according to the Schwartz formula. None of the children were deficient in folate or vitamin B12. After adjusting for age, folate, and vitamin B12, there was a modest and insignificant decrease of 0.033 micromol/L of Hcy associated with an increase of 1 mL/min of GFR (95% confidence interval, -0.066 to 0.0002). However, there was a strong and statistically significant association between log(SAH) and log(GFR): P < .0005, R2 = 0.76. This result suggests that plasma SAH rather than Hcy is the metabolite primarily affected in renal disease. We suggest that plasma Hcy elevations that have been linked to vascular disease may be due to elevated SAH resulting from renal insufficiency.

Topics: Adolescent; Child; Child, Preschool; Congenital Hypothyroidism; Folic Acid; Glomerular Filtration Rate; Homocysteine; Humans; Infant; Kidney Diseases; S-Adenosylhomocysteine; Vitamin B 12