[Leprechaunism: an inherited insulin resistance syndrome caused by the defect of insulin receptor].

OBJECTIVE

Leprechaunism is an inherited insulin resistance syndrome, caused by homozygous or compound-heterozygous mutations in the insulin receptor gene (INSR). Clinical and molecular genetic research was carried out in one 17-year old girl with leprechaunism and her family members.

METHODS

History and laboratory tests were routinely taken. DNA samples were obtained from the proband and 4 of the family members. PCR was done on all exons of INSR and the products of PCR were sequenced directly.

RESULTS

The proband had the following features: apparent cessation of growth, elfin-like face, emaciation, hirsutism and acanthosis nigricans. She had hyperglycemia (fasting blood glucose 15.8 mmol/L; glycosylated forms of hemoglobin 12%) and it was resistant to the treatment of insulin. She was found to have W659R mutation at 9 exon and V1054M mutation at 17 exon of INSR as heterozygotes. This compound mutation is a newly found type. For her father there was only V1054M mutation and her mother only W659R mutation. No mutation was identified in her sister.

CONCLUSION

The patient was diagnosed as leprechaunism according to her clinical presentations and biochemical examinations. The new transition mutation W659R at 9 exon and V1054M at 17 exon in INSR is the pathologic cause in this patient with leprechaunism.