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Objective:To detect the known hotspot mutations of GNAS in children with McCune-Albrigtht syndrome(MAS) by droplet digital PCR, and to explore its application value in the diagnosis of MAS.Methods:A total of 122 children with MAS were enrolled in the pediatric department of Ruijin Hospital Affiliated to Medical College of Shanghai Jiaotong University. For the known mutation hotspot of GNAS gene (R201H/C), dd-PCR, real-time fluorescent pyrophosphatic activation polymerase reaction (PAP) and second-generation sequencing were used to detect the presence of gene mutation and to analyse the relevance with the clinical features.Results:GNAS gene mutation was detected in 89 out of 122 children with MAS and 57 cases were found to have mutations. The positive rates of ddPCR, PAP, and second generation sequencing were 77.42%, 29.03%, and 56.25%, respectively. The GNAS gene mutation was detected in all classical triad patients. Among them, the positive rates of ddPCR in peripheral blood of typical and atypical children were 100% and 73.1% respectively, which were significantly higher than those of the other two methods. The detection rate of GNAS mutation in precocious puberty with bone lesions was higher than that in precocious puberty with skin lesions, suggesting that fibrous dysplasia with precocious puberty is an important basis for clinical diagnosis of MAS in children.Conclusion:Precocious puberty is the most common endocrine manifestation of MAS in children. Bone fibrous dysplasia with precocious puberty is an important factor in clinical diagnosis. ddPCR has high sensitivity, which can be helpful for molecular diagnosis of MAS.
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OBJECTIVE@#To evaluate the efficacy and safety of the third-generation aromatase inhibitor letrozole in the treatment of McCune-Albright syndrome (MAS) girls with peripheral precocious puberty.@*METHODS@#Twenty-one MAS girls with peripheral precocious puberty treated in Pediatrics Department of Ruijin Hospital, Shanghai Jiao Tong University School of Medicine from March 2012 to June 2017 were enrolled in the study. Patients presented with repeated vaginal bleeding, premature breast enlargement, café-au-lait spots or dysplasia of bone fibers, and low levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH); and the congenital adrenal hyperplasia, estrogen-producing tumors, and exogenous estrogen intake were excluded. Letrozole were administrated at a dose of 0.5-2 mg·m ·d for 6 to 12 months. The patients were observed for changes in breast staging, vaginal bleeding, sex hormone levels, liver function and bone age changes, and changes in uterine and ovarian volume.@*RESULTS@#After treatment, bone age/chronological age (BA/CA)was decreased from 1.23±0.30 to 1.11±0.18 ( < 0.01); the predicted adult height (PAH) increased from (156.2±5.9)cm to (158.4±2.1)cm after treatment ( < 0.05); the vaginal bleeding was reduced and the estradiol level decreased, while the teststosterone level and the uterus showed no significant increase, and no adverse reactions such as ovarian torsion and abnormal liver function were observed.@*CONCLUSIONS@#Precocious puberty is one of the most common endocrine manifestations in MAS. Our findings suggest that letrozole may be an effective and safe therapy to precocious puberty in girls with McCune-Albright Syndrome.