An association between precocious puberty and fragile X syndrome?

STUDY

OBJECTIVE

To determine the FMR1 gene status in a 10-year, 10-month-old girl with a history of precocious puberty and a family history of fragile X syndrome.

DESIGN

Case report.

SETTING

The outpatient facility of the Division of Adolescent Medicine and the Division of Genetic and Metabolic Disorders at Children's Hospital of Michigan and the Medical Genetics and Birth Defects Center of Henry Ford Hospital, Detroit, Michigan.

PARTICIPANT: A 10-year, 10-month-old girl with a history of precocious puberty.

INTERVENTION: Evaluation for menorraghia, DNA extraction, and fragile X gene analysis of blood samples from the patient and her mother.

MAIN OUTCOME MEASURES: Identification of a full mutation in the FMR1 gene.

RESULTS

Southern blot analysis of the FMR1 gene identified a full mutation in the daughter with approximately 750 repeats of the CGG sequence. Methylation studies showed that the full mutation was completely methylated. FMR1 DNA studies on her mother identified a premutation of approximately 100 repeats.

CONCLUSIONS

This report identifies a young girl with a history of precocious puberty and fragile X syndrome. It is also the first report of molecular genetic FMR1 studies in a female with precocious puberty. A possible association between the two conditions is suggested and warrants further investigation.