Rarity of congenital adrenal hyperplasia in children born very preterm:Possible mechanism and implication for newborn screening.

Introduction: Screening for congenital adrenal hyperplasia through the measurement of 17-hydroxyprogesterone on the neonatal blood spot aims to: a) prevent neonatal deaths; b) allow earlier identification and thereby decrease the severity of the initial salt-wasting episode; and c) shorten the time during which a severely virilized genetic female newborn may be assigned the male sex. It is now practiced in the majority of high-income countries, although the positive predictive value of the test is very low in infants born preterm, who seem to be infrequently affected. In almost all low- and middle-income countries, it has not yet been implemented.

Hypothyroidism due to biallelic variants in IYD: description of 4 families and a novel variant.

Biallelic loss-of-function variants in the IYD gene cause hypothyroidism resulting from iodine wasting. We describe 8 patients (from 4 families in which the parents are first cousins) who are homozygous for a variant in IYD (including a novel missense deleterious variant, c.791C>T [P264L], in 1 family).

Thyrotropin Screening of Newborns: Before or After 72 Hours of Life? Before Discharge or at Home?

Until November 2019 in Belgium, dried blood spot (DBS) sampling was performed between 72 and 120 hours of life, when a majority of newborns had already been discharged from the maternity. In November 2019, the policy for newborn screening in South Belgium changed to allow sampling as soon as 48 hours of life, with the objective to accelerate the process and to allow more sampling during the hospital stay. Our objective was to evaluate the impact of this policy modification and, in particular, to assess the effectiveness of screening for hypothyroidism based on sampling before or after 72 hours of life, as well as to compare the effectiveness of DBS collection before discharge or at home.