Current clinical management of constitutional delay of growth and puberty.

BACKGROUND: Constitutional delay of growth and puberty (CDGP) is classified as the most frequent cause of delayed puberty (DP). Finding out the etiology of DP during first evaluation may be a challenge. In details, pediatricians often cannot differentiate CDGP from permanent hypogonadotropic hypogonadism (PHH), with definitive diagnosis of PHH awaiting lack of puberty by age 18 yr. Neverthless, the ability in providing a precise and tempestive diagnosis has important clinical consequences. MAIN TEXT: A growth failure in adolescents with CDGP may occur until the onset of puberty; after that the growth rate increases with rapidity. Bone age is typically delayed. CDGP is generally a diagnosis of exclusion. Nevertheless, other causes of DP must be evaluated. A family history including timing of puberty in the mother and in the father as well as physical examination may givee information on the cause of DP. Patients with transient delay in hypothalamic-pituitary-gonadal axis maturation due to associated conditions, such as celiac disease, inflammatory bowel diseases, kidney insufficiency and anorexia nervosa, may experience a functional hypogonadotropic hypogonadism. PHH revealing testosterone or estradiol low serum values and reduced FSH and LH levels may be connected to abnormalities in the central nervous system. So, magnetic resonance imaging is required in order to exclude either morphological alterations or neoplasia. If the adolescent with CDGP meets psychological difficulties, treatment is recommended. CONCLUSION: Even if CDGP is considered a variant of normal growth rather than a disease, short stature and retarded sexual development may led to psychological problems, sometimes associated to a poor academic performance. A prompt and precise diagnosis has an important clinical outcome. Aim of this mini-review is throwing light on management of patients with CDGP, emphasizing the adolescent diagnosis and trying to answer all questions from paediatricians.

MKRN3 and KISS1R mutations in precocious and early puberty.

BACKGROUND: Pubertal timing is known to be influenced by interactions among various genetic, nutritional, environmental and socio-economic factors, although the ultimate mechanisms underlying the increase in pulsatile GnRH secretion at puberty have yet to be fully elucidated. The aim of our research was to verify the role of KISSR1 (previously named GPR54) and MKRN3 genes on pubertal timing. METHODS: We analyzed the DNA sequence of these genes in 13 girls affected by central precocious puberty (CPP) who showed onset of puberty before 8 years of age, and in 6 girls affected by early puberty (EP) between 8 and 10 years of age. RESULTS: Direct sequencing of the KISS1R (GPR54) gene revealed two SNPs. One SNP is a missense variant (rs 350,132) that has been previously reported in connection to CPP in Korean girls. The other variant that we found in the GPR54 gene (rs764046557) was a missense SNP located in exon 5 at position 209 of the aminoacid. We identified this variant in only one CPP patient. Automatic sequencing of MKRN3 in all patients revealed three variants in eight subjects. In 6 out of 19 (31.5%) patients (3/13 CPP patients and 3/6 EP patients) we found the synonymous variant c.663C > T (rs2239669). Another synonymous variant (rs140467331) was found in one of our CPP patients, as well as one missense variant (rs760981395) in another CPP patient. CONCLUSION: In conclusion, we identified sequence variations of the KISS1R and MKRN3 genes, two of the most frequent genetic causes of ICPP. Our results suggest that these variants might be inducible factors in the pathogenesis of CPP.