PLOD1 and central precocious puberty: Girls with CPP diagnosed between January 2016 and February 2020 were separated into two groups: Group 1 before the COVID-19 pandemic, and Group 2 during the pandemic from March 2020 until the end of June 2021. CPP was defined as breast development Tanner stage ≥2 before 8 years of age, and 1 or more of the following criteria: height velocity (HV) >6 cm/years, advanced bone age by at least 1 year, basal serum LH >0.3 U/L, peak LH >5 U/L after LH releasing hormone test, and negative brain magnetic resonance imaging (MRI).