The McCune-Albright syndrome without typical skin pigmentation

Area of Science:

• Pediatric Endocrinology
• Genetics
• Skeletal Dysplasias

Background:

• McCune-Albright syndrome (MAS) is a rare genetic disorder characterized by a triad of polyostotic fibrous dysplasia, precocious puberty, and café-au-lait skin pigmentation.
• MAS results from a postzygotic mutation in the GNAS gene, leading to mosaicism and variable clinical manifestations.
• Incomplete or atypical presentations of MAS can pose diagnostic challenges.

Observation:

• This report describes three pediatric female patients presenting with features suggestive of McCune-Albright syndrome.
• All three girls exhibited polyostotic fibrous dysplasia, a condition causing abnormal bone development.
• Precocious puberty, or early onset of puberty, was also a consistent finding in these patients.

Findings:

• A key finding was the absence of the typical abnormal skin pigmentation (café-au-lait spots) in all three described cases.
• The patients demonstrated an incomplete phenotype of McCune-Albright syndrome, highlighting phenotypic variability.
• This suggests that the absence of skin lesions does not exclude the diagnosis of MAS in the presence of other characteristic features.

Implications:

• The findings underscore the importance of considering McCune-Albright syndrome even in the absence of classic skin findings.
• Early diagnosis and management of polyostotic fibrous dysplasia and precocious puberty are crucial for optimal outcomes in affected children.
• Further research into the genetic and phenotypic spectrum of McCune-Albright syndrome is warranted to improve diagnostic accuracy and patient care.