A novel recessive splicing mutation in the POU1F1 gene causing combined pituitary hormone deficiency.
BACKGROUND
Mutations in the gene encoding the pituitary transcription factor POU1F1 (Pit-1, pituitary transcription factor-1) have been described in combined pituitary hormone deficiency (CPHD).


OBJECTIVE
The aim of this study was the characterisation of the molecular defect causing CPHD in a patient born to consanguineous parents.


METHODS
The case of a 12.5-yr-old girl presenting with severe growth failure at diagnosis (-3 SD score at 3 months) and deficiency of GH, PRL, and TSH was investigated for the presence of POU1F1 gene mutations by denaturing high performance liquid chromatography analysis.


RESULTS
A novel mutation adjacent to the IVS2 splicing acceptor site (IVS2-3insA) was identified in the patient at the homozygous state. Analysis of patient's lymphocyte mRNA and an in vitro splicing assay revealed the presence of 2 aberrant splicing products: a) deletion of the first 71 nucleotides of exon 3, altering the open reading frame and generating a premature stop codon, b) total exon 3 skipping resulting in an in frame deleted mRNA encoding a putative protein lacking part of the transactivation domain and of the POUspecific homeodomain. Notably, the patient's relatives heterozygous for the mutation had PRL levels under the normal range with no evident clinical symptoms.


CONCLUSIONS
The IVS2- 3insAmutation, responsible for CPHD at the homozygous state, causes the presence of 2 aberrant splicing products encoding non-functional products. In the heterozygotes one normal allele might not guarantee a complete pituitary function.
Carlomagno
Y
Y
Laboratory of Human Genetics, Department of Medical Sciences, Eastern Piedmont University and Interdisciplinary Research Center on Autoimmune Diseases, 28100 Novara, Italy.
Salerno
M
M
Vivenza
D
D
Capalbo
D
D
Godi
M
M
Mellone
S
S
Tiradani
L
L
Corneli
G
G
Momigliano-Richiardi
P
P
Bona
G
G
Giordano
M
M
D002648:Child; D003241:Consanguinity; D005260:Female; D017353:Gene Deletion; D019382:Human Growth Hormone / Q000172:deficiency; D006801:Humans; D010375:Pedigree; D010907:Pituitary Hormones / Q000172:deficiency*; D011388:Prolactin / Q000097:blood; D012326:RNA Splicing; D050817:Transcription Factor Pit-1 / Q000235:genetics*
C494187:POU1F1 protein, human; D010907:Pituitary Hormones; D050817:Transcription Factor Pit-1; D019382:Human Growth Hormone; D011388:Prolactin