INTRODUCTION: Genetic studies of familial central precocious puberty (CPP) have suggested that makorin ring finger protein 3 (MKRN3) is the primary inhibitor of gonadotropin-releasing hormone (GnRH) secretion. Obesity in girls can cause early puberty by affecting the hypothalamic–pituitary–gonadal (HPG) axis. This study evaluated the serum MKRN3 level of patients with CPP and its relationship with body mass index (BMI).
METHODS: The study included 92 CPP and 86 prepubertal healthy controls (HC) aged 6–10 years. The CPP and HC groups were divided into obese and non-obese subgroups to evaluate whether BMI affects MKRN3. Patients’ presenting complaints, chronological age, height age, bone age, Tanner stage, standard deviation scores for weight, height, and BMI, levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), and MKRN3, and pelvic ultrasonography findings were recorded.
RESULTS: The serum MKRN3 levels were lower in the CPP group and lowest in the CPP-obese subgroup. There were significant differences in MKRN3 levels between the CPP-obese and CPP-normal weight (p=0.02), CPP-obese and HC-obese (p<0.001), and CPP-obese and HC-normal weight (p=0.03) groups. MKRN3 and BMI were negatively correlated in all cases (r=–0.326, p<0.001).
DISCUSSION AND CONCLUSION: The negative correlation between BMI and MKRN3, and lower MKRN3 levels in CPP-obese patients, suggests that adipose tissue has a role in the onset of puberty. More comprehensive studies are needed to determine the relationship between MKRN3 and adipose tissue.