If a newborn with congenital hypothyroidism does not receive treatment, what feature might develop?

In cases of congenital hypothyroidism, if treatment is not administered, one significant consequence that can arise is physiological jaundice. This condition occurs due to the inability of the liver to effectively metabolize bilirubin, which can become elevated in newborns as a result of a variety of factors, including hypothyroidism.

Thyroid hormones play an essential role in the metabolism and detoxification processes in the body, including liver function. Specifically, thyroid hormones are involved in stimulating hepatic gluconeogenesis and influencing hepatic uptake and conjugation of bilirubin. Therefore, a deficiency in these hormones due to untreated congenital hypothyroidism can lead to an increased risk of jaundice in newborns, as the body struggles to manage bilirubin levels.

In contrast, the other options presented do not have a direct correlation with untreated congenital hypothyroidism. For example, microglossia, anal tags, and undescended testis may be related to different congenital conditions or developmental anomalies but are not consequences typically linked with the lack of treatment for congenital hypothyroidism. Hence, physiological jaundice is recognized as a potential complication in untreated cases, highlighting the importance of early diagnosis and intervention in infants diagnosed with congenital hypothyroidism.