The clinical characteristics of 10 cases and adult height of six cases of rare familial male-limited precocious puberty.

Objectives: Familial Male-Limited Precocious Puberty (FMPP) is a rare autosomal-dominant genetic condition with sexual dimorphism. We aim to summarize the clinical characteristics of FMPP patients and emphasize the use of a therapeutic regimen involving letrozole, spironolactone, and GnRHa, to augment clinician's understanding of the disease, thus enhancing patient care.

Methods: We retrospectively analyzed the clinical data of 10 FMPP patients and conducted follow-up assessments of adult height in six patients.

Results: Out of the 10 FMPP cases, five had the LHCGR M398T mutation, three exhibited the LHCGR A564G mutation, and two had the LHCGR T577I mutation. All patients initially presented with symptoms like penile enlargement, frequent erections, and rapid growth. Their median age at diagnosis was 4.67 years with bone age being 9 years. Four patients were untreated with a median adult height of 162 cm. Six patients underwent treatment between ages 3.58 and 5.5 years noting decreased frequency of erections, slower growth rate, and delayed bone age progression. Secondary Central Precocious Puberty (CPP) developed between ages 5 and 6.5 years in all cases, necessitating additional GnRHa treatment. Two treated cases reached an adult height of 176 cm and 173 cm, respectively, without any significant adverse effects.

Conclusions: The most prevalent genotype among FMPP patients in this study was the LHCGR M398T mutation. Early intervention using a regimen including letrozole and spironolactone, and later GnRHa, appears beneficial in limiting physical signs and improving adult height without major side effects. However, the longer-term effects on fertility require further investigation.