Objective. To assess results of newborn screening for 21-hydroxylase-deficient congenital adrenal hyperplasia (CAH) in Texas over 6 years of screening 1.9 million infants. Methods. In 1989, CAH was incorporated into the ongoing Texas Newborn Screening Program, which requires two screens on each newborn. 17-Hydroxyprogesterone was assayed, without extraction, by radioimmunoassay of blood collected from heel sticks onto filter paper collection cards. Infants with elevated levels of 17-hydroxyprogesterone were referred for evaluation, and those considered to have CAH were studied with respect to disease characteristics. Data were collected by pediatric endocrinologists using standardized forms that included type of CAH, results of laboratory tests, treatment regimen, disease symptoms and signs, and, for girls, degree of genital virilization. Results. The incidence of classic CAH in Texas is 1:16 008, with a ratio of salt-wasting to simple-virilizing of 2.7:1. A majority of infants detected were undiagnosed until screened, despite signs of salt-wasting or ambiguous genitalia. It was difficult to differentiate salt-wasting from simple-virilizing CAH in infants who were identified before the onset of adrenal insufficiency or electrolyte abnormalities. A substantial number of infants with nonclassic (NC) CAH also were detected. Not all infants were detected on the initial screen; 14% of infants with classic CAH and 87% with NC CAH were detected on the second routine screening test. Conclusions. Our findings confirm the benefits of newborn screening for CAH and the importance of a second screening test, and suggest that programs for newborn CAH screening must consider complex issues in diagnosis and treatment. These results also confirm that CAH is a continuum of disorders, rather than a disorder with discrete subtypes. In addition, the difficulties in differentiating CAH subtypes in newborns, and thus deciding appropriate treatment, and the high incidence of NC CAH suggest that standard diagnostic criteria and treatment regimens for CAH may need modification. Where screening exists, physicians will encounter more cases of CAH than in the past.

Newborn bloodspot screening (NBS) began in the early 1960s based on the work of Dr. Robert “Bob” Guthrie in Buffalo, NY, USA. His development of a screening test for phenylketonuria on blood absorbed onto a special filter paper and transported to a remote testing laboratory began it all. Expansion of NBS to large numbers of asymptomatic congenital conditions flourishes in many settings while it has not yet been realized in others. The need for NBS as an efficient and effective public health prevention strategy that contributes to lowered morbidity and mortality wherever it is sustained is well known in the medical field but not necessarily by political policy makers. Acknowledging the value of national NBS reports published in 2007, the authors collaborated to create a worldwide NBS update in 2015. In a continuing attempt to review the progress of NBS globally, and to move towards a more harmonized and equitable screening system, we have updated our 2015 report with information available at the beginning of 2024. Reports on sub-Saharan Africa and the Caribbean, missing in 2015, have been included. Tables popular in the previous report have been updated with an eye towards harmonized comparisons. To emphasize areas needing attention globally, we have used regional tables containing similar listings of conditions screened, numbers of screening laboratories, and time at which specimen collection is recommended. Discussions are limited to bloodspot screening.

Primary congenital hypothyroidism (CH) is a common and preventable cause of intellectual disability. The incidence rate of CH has been reported to be increasing in the United States, but the factors behind the observed rate increase are not known. We summarize here the data presented at a workshop on CH, at which factors potentially related to the CH-incidence-rate increase (namely, race, ethnicity, sex, and birth outcomes) were evaluated. Data sources for the analyses included a national data set of newborn-screening results and state-specific data from newborn-screening programs in California, Massachusetts, New York, and Texas. The incidence rate of CH increased in the United States by 3% per year; however, an increase did not occur in all states, at a constant rate, or even at the same rate. Analysis of US data (1991–2000) showed a CH-incidence-rate increase only among white newborns. More recently, in California (2000–2007), the rate was constant in non-Hispanic newborns, but it increased among Hispanic newborns. In the national data, the CH-incidence rate increased similarly among boys and girls, whereas in Texas (1992–2006), the rate among boys increased significantly more than among girls and varied according to race and ethnicity. In Massachusetts (1995–2007), low birth weight newborns or newborns who had a delayed rise in thyrotropin concentration accounted for the majority of the recent rate increase. Race, ethnicity, sex, and pregnancy outcomes have affected the observed increasing incidence rate of CH, although there have been some inconsistencies and regional differences. The association with preterm birth or low birth weight could reflect the misclassification of some cases of transient hypothyroxinemia as true CH. Future studies of risk factors should focus on correct initial identification and reporting of demographic characteristics and pregnancy outcomes for cases of CH. In addition, long-term follow-up data of presumed cases of CH should be ascertained to differentiate true cases of CH from cases of transient hypothyroidism.