MONOALLELIC EXPRESSION OF NORMAL MESSENGER-RNA IN THE PIT1 MUTATION HETEROZYGOTES WITH NORMAL PHENOTYPE AND BIALLELIC EXPRESSION IN THE ABNORMAL PHENOTYPE
N. Okamoto et al., MONOALLELIC EXPRESSION OF NORMAL MESSENGER-RNA IN THE PIT1 MUTATION HETEROZYGOTES WITH NORMAL PHENOTYPE AND BIALLELIC EXPRESSION IN THE ABNORMAL PHENOTYPE, Human molecular genetics, 3(9), 1994, pp. 1565-1568
The combined deficiency of thyrotropin, growth hormone and prolactin,
caused by PIT1 abnormality manifests in the homozygous or heterozygous
state. We studied a patient having an allele with Arg271Trp mutation,
which produces clinical symptoms in heterozygotes by a dominant-negat
ive effect. However, in the family, her father, grandmother and aunts
had the same mutation without clinical symptoms, although the proband
had typical phenotypic expression. We analyzed the PIT1 transcript in
peripheral lymphocytes by reverse transcription polymerase chain react
ion and found monoallelic expression of normal allele in the father an
d grandmother and skewed pattern of biallelic expression in the proban
d. The phenotypic expression of PIT1 abnormality may depend on differe
nt transcription of the PIT1 gene.