A novel germline mutation, IVS4+1G>A, of the POU1F1 gene underlying combined pituitary hormone deficiency.

BACKGROUND

POU1F1 is a pituitary transcription factor that plays a pivotal role in pituitary development and expression of the GH, PRL and TSH beta genes. Therefore, abnormalities of the POU1F1 gene are known to be responsible for a phenotype causing combined pituitary hormone deficiency (CPHD) involving growth hormone, prolactin and thyrotropin.

METHODS

We described an 18-year-old Thai man, from a consanguineous family, who presented with short stature and cognitive deficit. He underwent endocrinological and molecular investigations.

RESULTS

Hormonal studies showed that the patient had GH deficiency and secondary hypothyroidism, consistent with CPHD. Direct DNA sequencing revealed a novel homozygous mutation at the splice site of exon 4, IVS4+1G>A. It is the first splice site mutation in the POU1F1 gene described to date. Of the 7 other family members studied for this mutation by restriction enzyme digestions, 5 were heterozygous. They were all unaffected, suggesting a recessive pattern of inheritance.

CONCLUSIONS

We described a novel POU1F1 splice site mutation, IVS4+1G>A, the first of its kind, in a Thai patient with CPHD. Recessive inheritance is suggested. We also noted preventable morbidities which resulted from delay in diagnosis of concomitant pituitary hormone defects in newborns suspected of CPHD.