Clinical course of peripheral precocious puberty in girls due to autonomous ovarian cysts.

OBJECTIVE: Peripheral precocious puberty (PPP) is the precocious development of secondary sexual characteristics without pulsatile gonadotropin-releasing hormone (GnRH) secretion. In girls, PPP suggests a hyper-oestrogenic state, such as autonomous ovarian cysts and McCune-Albright syndrome (MAS). We aimed to investigate PPP in girls with ovarian cysts, with or without MAS. DESIGN: A retrospective study design was used. PATIENTS AND MEASUREMENTS: The study included 12 girls diagnosed with ovarian cysts with PPP between January 2003 and May 2022. Pelvic sonography was performed in cases of vaginal bleeding or areolar pigmentation in PPP. The clinical characteristics, clinical course and pelvic sonographic findings of girls with ovarian cysts were investigated. RESULTS: We found 18 episodes of ovarian cysts in the 12 girls. The median size of the ovarian cysts was 27.5 mm. Five of the girls were diagnosed with MAS. The median time to spontaneous regression was 6 months. Later, 4 out of 12 girls progressed to central precocious puberty (CPP), and three of them had a recurrence of ovarian cysts. Compared to the non-recurrent and recurrent groups, there was a difference in peak luteinizing hormone (LH) in the GnRH stimulation test and period to cyst regression. CONCLUSIONS: Most ovarian cysts in PPP spontaneously disappear. However, this could be one of the findings of MAS. Some girls progress from PPP to CPP. Therefore, follow-up is necessary for ovarian cysts in patients with PPP. The recurrence of ovarian cysts may occur when spontaneous regression is prolonged.

Reference Ranges of Body Composition Using Dual-Energy X-Ray Absorptiometry and Its Relation to Tri-Ponderal Mass Index.

Introduction/background Increased body fat is related to obesity and its comorbidities later in life. To determine the amount of body fat in children and adolescents, reference intervals should be applied. Dual-energy X-ray absorptiometry (DXA) is a good tool for accurately measuring body composition. Methodology The body composition reference ranges in Korean children and adolescents were determined using nationally representative cross-sectional data. The performances of the body mass index (BMI) and tri-ponderal mass index (TMI) in measuring body fat were compared using the reference percentiles derived from this analysis. Results A total of 1,661 subjects (891 boys and men and 770 girls and women) were included. Age- and sex-specific percentiles and the corresponding LMS variables for DXA-assessed parameters for the whole body and the trunk were determined. The coefficients of determination of the whole body FM SDS and FMI SDS for the BMI SDS were 0.783 and 0.784, respectively, and those for the TMI SDS were 0.685 and 0.769, respectively. Conclusion Based on the reference values for body composition, the correlation coefficients of TMI for adjusted FM measured by DXA were comparable to those of BMI. TMI estimated body fat levels more accurately than BMI in this study population.

Aberrant Notch Signaling Pathway as a Potential Mechanism of Central Precocious Puberty.

The Notch signaling pathway is highly conserved during evolution. It has been well documented that Notch signaling regulates cell proliferation, migration, and death in the nervous, cardiac, and endocrine systems. The Notch pathway is relatively simple, but its activity is regulated by numerous complex mechanisms. Ligands bind to Notch receptors, inducing their activation and cleavage. Various post-translational processes regulate Notch signaling by affecting the synthesis, secretion, activation, and degradation of Notch pathway-related proteins. Through such post-translational regulatory processes, Notch signaling has versatile effects in many tissues, including the hypothalamus. Recently, several studies have reported that mutations in genes related to the Notch signaling pathway were found in patients with central precocious puberty (CPP). CPP is characterized by the early activation of the hypothalamus-pituitary-gonadal (HPG) axis. Although genetic factors play an important role in CPP development, few associated genetic variants have been identified. Aberrant Notch signaling may be associated with abnormal pubertal development. In this review, we discuss the current knowledge about the role of the Notch signaling pathway in puberty and consider the potential mechanisms underlying CPP.

Low Bone Mineral Density at Initial Diagnosis in Children and Adolescents with Graves' Disease.

Previous studies have reported reduced bone mineral density (BMD) in patients with hyperthyroidism. We assessed the association of BMD in children and adolescents with Graves' disease (GD) after correcting for potential confounders affecting BMD such as age, sex, and pubertal status. Forty-four children and adolescents with GD and 172 age- and sex-matched healthy controls were enrolled in this study. We analyzed auxological features, BMD, and levels of thyroid hormone, thyroid-stimulating hormone, and thyroid autoantibodies. We measured BMD by dual-energy X-ray absorptiometry at the time of diagnosis in all patients. The mean age of all patients with GD (9 boys and 32 girls) was 12.1 ± 2.2 years (range, 7.0-16.0). Their initial mean free T4 and thyroid-stimulating hormone levels were 3.51 ± 1.56 ng/dL and 0.04 ± 0.03 IU/L, respectively. The mean BMD Z-scores of the lumbar spine (LS), femoral neck, and total body less head of patients with GD were significantly lower than those of control subjects. Eleven patients (26.8%) had low bone density (LS BMD Z-scores < -2.0). To identify correlations of patient characteristics with BMD Z-scores at each site, alkaline phosphatase had a significant negative correlation with BMD Z-scores at LS and femoral neck, but not total body less head (r = -0.441; p = 0.004 and r = -0.351; p = 0.025, respectively). Children and adolescents with newly diagnosed GD had lower bone mass than their healthy peers. These results suggest that BMD measurement at initial evaluation may be necessary in this population.

Impact of Type 2 Diabetes Mellitus and Antidiabetic Medications on Bone Metabolism.

PURPOSE OF REVIEW: This review focuses on the complex interactions between hyperglycemia and bone fragility and the effects of antidiabetic medications on bone metabolism. RECENT FINDINGS: Type 2 diabetes (T2D) is associated with increased risk of bone fracture even in those with increased or normal bone mineral density (BMD). The pathophysiology of diabetic bone disease is not completely understood, but it is thought to be multifactorial and associated with complex cross talk among factors such as AGEs, IGF-1, enteric hormones, and pro-inflammatory cytokines. Treatment for T2D may have an impact on bone metabolism. Diabetic bone disease should be considered a serious complication of long-standing T2D.

Identification of rare missense mutations in NOTCH2 and HERC2 associated with familial central precocious puberty via whole-exome sequencing.

Objective: Genetic factors play a critical role in pubertal progression; however, mutations associated with central precocious puberty (CPP) have been reported only in four genes: KISS1, KISS1R, DLK1, and MKRN3. This study aimed to identify novel, potentially pathogenic variants in patients with familial CPP via whole-exome sequencing (WES).Methods: WES analysis was applied in 28 patients (25 girls and three boys) belonging to 14 families, wherein all siblings were diagnosed with CPP. Data analysis aimed to select only very rare variants (minor allele frequency <1%). Nonsense, splice-site, and frameshift variants were considered the most ideal candidate variants. Additionally, non-synonymous missense variants predicted as being deleterious using in silico analysis tools were further considered.Results: The analysis of exome sequencing data resulted in the identification of rare mutations in two promising candidate genes (NOTCH2 and HERC2) in a family. Siblings with CPP exhibited two heterozygous missense mutations (p. Leu15Phe in NOTCH2 and p. Arg4081His in HERC2). Moreover, their parents without history of CPP had a missense variant in either NOTCH2 or HERC2.Conclusions: We identified new candidate genes with potential roles in pubertal development. Digenic inheritance of the two genetic mutations associated with the Notch signaling pathway may have a synergistic effect resulting in CPP.

The Relationship Between Bone Mineral Density and Type 2 Diabetes in Obese Children and Adolescents at the Time of Initial Diagnosis.

Long-term effects of type 2 diabetes mellitus (T2D) on bone health remain unclear. The objective of this study was to assess the possible association of bone mineral density (BMD) at multiple sites with T2D after correcting for several potential confounders such as age, sex, Tanner stage, and BMI known to affect BMD in adolescents with newly developed T2D. In this cross-sectional study, 17 children and adolescents with T2D and 59 age, sex, and BMI-matched controls were included. All subjects underwent dual-energy X-ray absorptiometry to measure regional and whole-body composition with Lunar Prodigy at the time of initial diagnosis. A BMD Z-score was calculated using data from healthy Korean children and adolescents after adjusting for height-for-age. The mean age of all subjects was 12.9±2.4 years (range, 8.3-18.3 years). BMDht Z-scores for lumbar spine and total body after adjusted for age, sex, BMI SDS, and Tanner stage were not significantly different between patients and controls. However, BMDht Z-scores for femur neck and bone mineral apparent density (BMAD) Z-scores of lumbar spine were significantly lower in T2D patients than those in healthy controls. HOMA-IR or HbA1c was not associated with BMDht Z-scores at multiple sites. BMDht Z-scores at multiple sites except femur neck in adolescents with newly developed T2D were similar to those in obese controls after adjustment for potential confounders.

Prevalence of Pathological Brain Lesions in Girls with Central Precocious Puberty: Possible Overestimation?

BACKGROUND: Brain magnetic resonance imaging (MRI) is routinely performed to identify brain lesions in girls with central precocious puberty (CPP). We aimed to investigate the prevalence and type of brain lesions among Korean girls with CPP and evaluate the need for routine brain MRI examinations. METHODS: This retrospective cross-sectional study evaluated data on 3,528 girls diagnosed with CPP from April 2003 to December 2016, and identified 317 girls who underwent sellar MRI. Exclusion criteria were patients with a known brain tumor or who did not undergo brain MRI due to refusal or the decision of the pediatric endocrinologist. RESULTS: Normal sellar MRI findings were observed in 291 of the 317 girls (91.8%). Incidental findings were observed in 26 girls (8.2%). None of the patients had pathological brain lesions. CONCLUSION: The prevalence of intracranial lesions among girls who were generally healthy and without neurological symptoms but diagnosed with CPP was lower than that previously reported. Furthermore, none of the identified lesions required treatment. It may be prudent to reconsider the routine use of brain MRI to screen all patients with CPP, especially if they are healthy and neurologically asymptomatic, and are girls aged 6-8 years.

No association between estrogen receptor gene polymorphisms and premature thelarche in girls.

OBJECTIVE: Premature thelarche (PT) is a benign, nonprogressive condition defined as isolated breast development. While the pathophysiology of PT remains unclear, increased sensitivity to estrogen may cause PT. The aim of this study was to investigate the association between polymorphisms in the estrogen receptor alpha (ERα) gene and PT in girls. METHODS: In this case-control study, we examined 96 girls referred for early breast development (before the age of 8 years). The control group included healthy Korean females with normal pubertal progression. Anthropometric and hormonal parameters were measured and PvuII and XbaI ERα gene polymorphisms were evaluated by PCR. Out of the 96 girls, all coding exon and exon-intron boundaries of ERα were sequenced from the DNA of 46 girls. RESULTS: There was no significant difference in the distribution of PvuII and XbaI polymorphisms between patients and controls. However, the carriers of XbaI polymorphisms had more advanced Tanner stage than did the non-carriers. Also, four ERα gene polymorphisms were previously identified, but these polymorphisms had no clinical significance. CONCLUSION: No association was found between the ERα gene polymorphisms and PT in girls. However, XbaI polymorphisms may contribute to early breast budding.

Multiple Endocrine Neoplasia Type 1 Presenting as Hypoglycemia due to Insulinoma.

Multiple endocrine neoplasia (MEN) mutation is an autosomal dominant disorder characterized by the occurrence of parathyroid, pancreatic islet, and anterior pituitary tumors. The incidence of insulinoma in MEN is relatively uncommon, and there have been a few cases of MEN manifested with insulinoma as the first symptom in children. We experienced a 9-year-old girl having a familial MEN1 mutation. She complained of dizziness, occasional palpitation, weakness, hunger, sweating, and generalized tonic-clonic seizure that lasted for 5 minutes early in the morning. At first, she was only diagnosed with insulinoma by abdominal magnetic resonance images of a 1.3 x 1.5 cm mass in the pancreas and high insulin levels in blood of the hepatic vein, but after her father was diagnosed with MEN1. We found she had familial MEN1 mutation, and she recovered hyperinsulinemic hypoglycemia after enucleation of the mass. Therefore, the early genetic identification of MEN1 mutation is considerable for children with at least one manifestation.

Association of aromatase (TTTA)n repeat polymorphisms with central precocious puberty in girls.

OBJECTIVE: Precocious puberty is characterized by early activation of the pituitary-gonadal axis. Oestrogen is the final key factor to start the onset of puberty. The cytochrome P450 19A1 (CYP19A1) gene encodes an aromatase that is responsible for the conversion of androgens to oestrogen, which is a key step in oestrogen biosynthesis. The aim of this study was to identify CYP19A1 gene mutations or polymorphisms in girls with central precocious puberty (CPP). METHODS: We evaluated the frequency of allelic variants of the CYP19A1 exons and the tetranucleotide tandem repeat (TTTA)n in intron 4 in 203 idiopathic central precocious puberty (CPP) girls and 101 normal healthy women. RESULTS: The genotype analysis of the CYP19A1 (TTTA)n polymorphism revealed six different alleles ranging from seven to 13 repeats. Among the six different repeat alleles detected in this study, the (TTTA)13 repeat allele was only detected in the patient group and carriers of the (TTTA)13 allele were significantly associated with an increased risk of CPP (OR = 1·509, 95% CI = 1·425-1·598, P = 0·033). Carriers of the (TTTA)13 repeat allele were significantly younger at pubertal onset and had higher levels of oestrogen than noncarriers of the (TTTA)13 repeat allele. Although nine polymorphisms were detected in exons of the CYP19A1 gene, no clinical significance was observed. CONCLUSION: In this study, carriers of a higher repeat (TTTA)13 polymorphism in intron 4 of the CYP19A1 gene had higher levels of oestrogen. Those carrying the (TTTA)13 repeat allele may have a higher risk of developing CPP.

Waist-height ratio and body mass index as indicators of obesity and cardiometabolic risk in Korean children and adolescents.

PURPOSE: We assessed the clinical relevance of waist-height ratio (WHtR) as an indicator of cardiometabolic risk and body fat mass measured by dual-energy x-ray absorptiometry (DXA) among Korean children and adolescents. METHODS: Data from 1,661 children and adolescents aged 10-18 years who participated in the Korea National Health and Nutrition Examination Survey were analyzed. Unadjusted Pearson correlation, age- and sex-adjusted Pearson correlation, and multiple linear regression analyses were performed to investigate the relationships between WHtR standard deviation score (SDS) and cardiometabolic risk factors, as well as DXA-assessed parameters. RESULTS: WHtR SDS was correlated with cardiometabolic risk factors, including systolic blood pressure, glucose, total cholesterol, high-density lipoprotein cholesterol, triglyceride, and low-density lipoprotein cholesterol, as well as DXA-assessed parameters such as lean mass SDS, fat mass SDS, and fat mass percentage SDS in both whole body and trunk using an adjusted Pearson correlation analyses among all participants (p<0.001). WHtR SDS was strongly correlated with whole-body fat mass and trunk fat mass (r=0.792, p<0.001 and r=0.801, p<0.001, respectively) whereas WHtR SDS had a low correlation coefficient with whole-body lean mass and trunk lean mass SDS (r=0.512, p<0.001 and r=0.487, p<0.001, respectively). In multiple linear regression analyses, WHtR SDS was significantly associated with whole-body and trunk fat mass after adjustment for confounders. CONCLUSION: Cardiometabolic risk factors and body fat mass assessed by DXA in Korean children and adolescents were highly correlated with WHtR. Additionally, WHtR has an advantage in distinguishing fat-free mass. WHtR can be a useful and convenient clinical indicator of cardiometabolic risk factors.

Ectopic lingual thyroid with subclinical hypothyroidism in children.

OBJECTIVES: Lingual thyroid is a rare condition that affects approximately 1 in 100,000 individuals. Although it is usually detected in the pediatric population through newborn screening tests or evaluation of congenital hypothyroidism, there are cases in which it remains undetected until adulthood or until symptoms arise because of glandular enlargement. The possible symptoms of lingual thyroid include foreign body sensation in the throat, dysphagia, dyspnea, and hemorrhage. Several cases of lingual thyroid are asymptomatic and accompanied by subclinical hypothyroidism. Herein, we present three cases of lingual thyroid treated with thyroid hormone suppressive therapy. CASE PRESENTATION: The three patients sought medical attention because of a sore throat or foreign body sensation in the throat. Their newborn screening tests and developmental histories were normal. These patients exhibited subclinical hypothyroidism and were treated with hormone suppression therapy. CONCLUSIONS: Patients with lingual thyroid frequently exhibit subclinical hypothyroidism. Hormone treatment may help to reduce the size of the ectopic thyroid and improve symptoms. If an increase in size is noted during follow-up or symptoms do not improve, surgical treatments may be considered.

Impact of body mass index on luteinizing hormone secretion in gonadotropin-releasing hormone stimulation tests of boys experiencing precocious puberty.

OBJECTIVE: Excess adiposity may influence various aspects of pubertal development, including the timing of pubertal initiation and hormonal parameters during puberty. The aim of the study was to evaluate the impact of body mass index (BMI) on luteinizing hormone (LH) secretion to gonadotropin-releasing hormone (GnRH) stimulation test in boys with precocious puberty. METHODS: Boys with precocious puberty, who were normal weight, overweight, and obese underwent GnRH stimulation tests between 2003 and 2010. Subjects were classified as normal weight (BMI ≥5th percentile and BMI <85th percentile), overweight (BMI ≥85th percentile and BMI <95th percentile), and obese (BMI ≥95th percentile). RESULTS: Of 56 children whose data were included in the final analysis, mean age at diagnosis was 8.7 ± 1.0 years. The majority of boys were of normal weight (n = 28, 50%), while 15 children (26%) were overweight, and 13 (23%) obese. Peak LH levels after GnRH stimulation were 19.8 ± 8.8, 9.0 ± 3.5, and 8.1 ± 4.0 mIU/ml among normal weight, overweight, and obese subjects, respectively (p < 0.001 for all comparisons). By multivariate analysis, there was a significant negative association of BMI with peak-stimulated LH level. CONCLUSIONS: The higher BMI is associated with lower LH response to the GnRH stimulation test in boys experiencing precocious puberty. In boys with precocious puberty, BMI should be considered when interpreting GnRH stimulation test.

Estrogen receptor α gene analysis in girls with central precocious puberty.

OBJECTIVE: Estrogen is the final key factor that triggers the onset of puberty. The raised sensitivity of estrogen receptor, which may be caused by an estrogen receptor α (ERα) gene mutation or polymorphism, has been implicated in the etiology of precocious puberty. The aim of this study is to identify ERα gene mutations or polymorphisms in girls with central precocious puberty (CPP). METHODS: A total of 204 Korean girls with CPP were included in this study along with 102 healthy Korean female adults as controls. All coding exons and exon-intron boundaries of the ERα gene were sequenced. The relationship between identified sequence variations and CPP were evaluated via comparison of allele frequencies between the two groups. RESULTS: Eight polymorphisms were identified in the ERα gene. Among the eight polymorphisms in this study, five have been previously reported, whereas the other three were novel polymorphisms. Two of the three novel polymorphisms, p.G145S in exon 1 and p.R555H in exon 8 were only identified in the patient group. The subgroup with p.G145S showed a significantly higher level of peak luteinizing hormone than the subgroup without p.G145S in girls with CPP. CONCLUSION: The scanning and typing of ERα polymorphism has uncovered several potentially meaningful polymorphisms. However, no solid conclusion can be made from this study and further studies are necessary to validate the function of these polymorphisms.

Effect of gonadotropin-releasing hormone agonist monotherapy and combination therapy with growth hormone on final adult height in girls with central precocious puberty.

This study aimed to compare clinical parameters, including final adult height (FAH), in girls with central precocious puberty treated with gonadotropin-releasing hormone agonists (GnRHa) with and without growth hormone (GH). This retrospective study reviewed data of 210 girls with precocious puberty who had reached FAH in a long-term trial of GnRHa treatment. The subjects were divided into the GnRHa treatment group (n = 188), and the combined GnRHa + GH treatment group (n = 22). Chronological age, bone age, height, height standard deviation score, predicted adult height (PAH), FAH, Tanner stage, and hormone levels were assessed during the treatment period. At the start of treatment, PAH was 156.35 ± 6.34 cm in the GnRHa monotherapy group and 150.41 ± 5.32 cm in the GnRHa + GH group (P < 0.001). At the end of treatment, PAH was 166.25 ± 5.26 cm in the GnRHa group and 164.07 ± 4.99 cm in the combined GnRHa + GH treatment group, which had increased compared to the start of treatment. The FAH in the GnRHa group and GnRHa + GH combination group were 161.07 ± 4.78 cm and 159.63 ± 3.8 6 cm, respectively, without significant difference. In addition, the height gain (FAH-PAH) was significantly higher in the GnRHa + GH group than the GnRHa group (9.22 ± 6.03 cm vs. 4.72 ± 5.01 cm, P < 0.001). In girls with central precocious puberty, the height gain in the FAH compared to PAH at the start of treatment was significantly higher with the GnRHa + GH combination treatment.

Association of serum uric acid Levels with metabolic syndromes in Korean adolescents.

Introduction: The study findings investigated uric acid reference values and their association with a cluster of cardiometabolic risk factors among adolescents using the Korea National Health and Nutrition Examination Survey (KNHANES). Methods: A retrospective cross-sectional study was conducted using the KNHANES database from 2016 to 2018, involving a total of 2,462 participants aged between 10 and 18 years. Based on age- and sex-specific percentile curves for serum uric acid (SUA) levels from the KNHANES, we examined the correlation between cardiometabolic risk factors and serum uric acid levels. Results: The percentile values of SUA varied with sex and age. In male subjects, SUA levels tended to increase from 10 to 14 years of age and plateaued after 14 years of age. Moreover, the overall uric acid level in females was found to be lower than that in males; the levels tended to increase at approximately 10 to 12 years old but were relatively consistent according to age. Mean uric acid levels increased according to obesity status in both males and females. However, correlation analysis revealed that SUA levels were associated with several metabolic risks even after adjusting for obesity. The detailed metabolic syndrome (MetS) components that were observed to be associated with an increase in uric acid levels were different between males and females, but overall, high uric acid levels increased MetS risk. Additionally, a significant increase in MetS-related odds ratio (OR) for components, including waist circumference (WC), triglyceride (TG) levels, and low high-density lipoprotein cholesterol (HDL-c), was observed. However, differences between sexes were apparent, with a more pronounced increase in OR based on SUA levels in girls. Discussion: SUA levels were closely associated with MetS and its components, even in nonobese subjects. Therefore, high SUA levels in children and young adolescents should be closely monitored to prevent MetS.

Treatment of congenital hypogonadotropic hypogonadism in male patients.

Congenital hypogonadotropic hypogonadism (CHH) is characterized by complete or partial failure of pubertal development because of inadequate secretion of gonadotropic hormones. CHH consists of hypogonadotropic hypogonadism with anosmia or hyposmia, Kallmann syndrome, and the normosmic variation normosmic idiopathic hypogonadotropic hypogonadism. CHH is one of the few treatable diseases of male infertility, although men with primary testicular dysfunction have irreversibly diminished spermatogenic capacity. The approach to CHH treatment is determined by goals such as developing virilization or inducing fertility. This review focuses on the current knowledge of therapeutic modalities for inducing puberty and fertility in men with CHH.

Hyperosmolar hyperglycemic state as the first manifestation of type 1 diabetes mellitus in an adolescent male: a case report.

A hyperosmolar hyperglycemic state (HHS) is a life-threatening complication rarely seen in children and adolescents with type 1 diabetes mellitus (T1DM). However, early diagnosis and proper treatment are vital to reduce the high morbidity and mortality rates associated with HHS. We describe a male patient who presented with polydipsia, polyuria, and a drowsy mental status. His initial biochemistry results demonstrated severe hyperglycemia (1,456 mg/dL), hyperosmolarity of 359 mOsm/kg (effective osmolarity, 323 mOsm/kg), and mild acidosis (venous pH, 7.327). The patient was diagnosed with HHS and T1DM based on the presence of hyperosmolarity, hyperglycemia, and positivity for antiglutamic acid antibodies. Intensive intravenous fluid and regular insulin (0.025 units/kg/hr) were administered. After hydration and insulin treatment, the patient's mental status and serum glucose and sodium levels improved, and no neurological complications were observed. In summary, most cases of HHS are observed in adult patients with type 2 diabetes. However, occurrences in children and adolescents with T1DM have also been reported. Therefore, HHS should be considered in the differential diagnosis of hyperglycemic emergencies.

Genetic factors in precocious puberty.

Pubertal onset is known to result from reactivation of the hypothalamic-pituitary-gonadal (HPG) axis, which is controlled by complex interactions of genetic and nongenetic factors. Most cases of precocious puberty (PP) are diagnosed as central PP (CPP), defined as premature activation of the HPG axis. The cause of CPP in most girls is not identifiable and, thus, referred to as idiopathic CPP (ICPP), whereas boys are more likely to have an organic lesion in the brain. ICPP has a genetic background, as supported by studies showing that maternal age at menarche is associated with pubertal timing in their offspring. A gain of expression in the kisspeptin gene (KISS1), gain-of-function mutation in the kisspeptin receptor gene (KISS1R), loss-of-function mutation in makorin ring finger protein 3 (MKRN3), and loss-of-function mutations in the delta-like homolog 1 gene (DLK1) have been associated with ICPP. Other genes, such as gamma-aminobutyric acid receptor subunit alpha-1 (GABRA1), lin-28 homolog B (LIN28B), neuropeptide Y (NPYR), tachykinin 3 (TAC3), and tachykinin receptor 3 (TACR3), have been implicated in the progression of ICPP, although their relationships require elucidation. Environmental and socioeconomic factors may also be correlated with ICPP. In the progression of CPP, epigenetic factors such as DNA methylation, histone posttranslational modifications, and noncoding ribonucleic acids may mediate the relationship between genetic and environmental factors. CPP is correlated with short- and long-term adverse health outcomes, which forms the rationale for research focusing on understanding its genetic and nongenetic factors.