The value of time in assessing the effectiveness of newborn screening for congenital adrenal hyperplasia

A pilot study on newborn screening for congenital adrenal hyperplasia in Beijing

Background A provisionary screening programme for 21-hydroxylase deficiency (21-OHD) was initiated in Beijing in 2014. The aim of this study was to investigate the incidence and the associated clinical characteristics of neonatal congenital adrenal hyperplasia (CAH) in Beijing and to provide evidence-based guidance for its application in CAH screening. Methods Live birth newborns (n=44,360) were screened for CAH in Beijing from July 2014 to April 2018. The levels of 17-hydroxyprogesterone (17-OHP) in the blood were estimated using the time-resolved fluoroimmunoassay. Neonates with a positive result and a level >30 nmol/L of 17-OHP were called for a retest. CAH was diagnosed based on further laboratory findings combined with clinical signs, such as weight loss, feeding difficulties, skin pigmentation, and atypical genitalia. Through a review of medical records, the clinical findings including molecular data were reported. Results Of the 44,360 neonates screened, 280 cases were deemed positive. Of these, 203 neonates were recalled for further tests and six patients (three boys and three girls) were diagnosed with CAH. Five cases of classic salt-wasting and one case of simple virilising 21-OHD were identified. The incidence of CAH in Beijing was 1:7393. The most frequent 21-OHD mutation was c.293-13C/A>G. Conclusions The incidence of CAH in Beijing was higher than the national average. The results support the need for neonatal CAH screening in Beijing. This pilot study demonstrates the clinical characteristics of 21-OHD through newborn screening. Early detection and treatment through neonatal screening may reduce mortality rates and optimise developmental outcomes.

Pregnanetriolone in paper-borne urine for neonatal screening for 21-hydroxylase deficiency: The place of urine in neonatal screening

The standard method of primary neonatal screening for congenital adrenal hyperlasia (CAH), determination of 17-hydroxyprogesterone (17OHP) in heelprick blood, is the object of recurrent controversy because of its poor diagnostic and economic efficiency. The superior ability of urinary pregnanetriolone levels to discriminate between infants with and without classical CAH has been known for some time, but has not hitherto been exploited for primary screening. Here we propose an economical neonatal CAH-screening system based on fluorimetric determination of the product of reaction between urinary pregnanetriolone and phosphoric acid.

Biochemical and genetic diagnosis of 21-hydroxylase deficiency

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency is caused by mutations in the CYP21A2 gene and is often fatal in its classic forms if not treated with glucocorticoids. In contrast, non-classic CAH (NCCAH), with a prevalence from 0.1 % up to a few percentages in certain ethnic groups, only results in mild partial cortisol insufficiency and patients survive without treatment. Most NCCAH cases are never identified, but unnecessary suffering due to hyperandrogenism, especially in females, can be avoided by a correct diagnosis. A 17-hydroprogesterone (17OHP) level above 300 nmol/L indicates classic CAH while 30-300 nmol/L in adult males or females (follicular phase or if anovulatoric) indicates NCCAH. The gold standard for diagnosing NCCAH is the ACTH stimulation test. Deletion, large gene conversions, and nine microconversion-derived mutations are the most common CYP21A2 mutations. However, almost 200 rare mutations have been described. Since there is a good genotype-phenotype relationship, genotyping provides valuable diagnostic, as well as prognostic information. Neonatal screening for CAH is now performed in an increasing number of countries with the main goal of reducing mortality and morbidity due to salt-losing adrenal crises in the newborn period. In addition, screening may shorten the time to diagnosis in virilized girls. Neonatal screening misses some patients with milder classic CAH and most NCCAH cases. In conclusion, diagnosing classic CAH is life-saving, but diagnosing NCCAH is also important to prevent unnecessary suffering.