Phenotypes Associated with This Genotype

Genotype
MGI:3653705

• Allelic Composition: Nkx2-1^tm2Shk/Nkx2-1^tm2Shk; Tg(TPO-cre)1Shk/0
• Genetic Background: involves: 129X1/SvJ * FVB/NCr

• ♀: phenotype observed in females
• ♂: phenotype observed in males
• N: normal phenotype

endocrine/exocrine glands

abnormal thyroid follicle morphology ( J:111027 )

• glands consist mostly of atrophic or degenerative follicles, and multiple smaller follicles lined by cuboidal to columnar epithelial cells in various ratios; atrophic/degenerative follicles had various sizes and shapes and are lined with flattened to cuboidal epithelial cells

• colloid in the lumen of cells in these follicles is partially or almost completely depleted

• most of these cells have lost Titf1 expression

• space between normal and atrophic/degenerative follicles is filled with small follicles resembling hyperplastic thyroid follicles containing little or no colloid in their lumens

• cultured follicular cells form irregular-shaped polygonal structures lacking colloid accumulation compared to mature, spherical colloid-containing follicles formed by cells from Titf1^tm2Shk homozygotes

small thyroid gland ( J:111027 )

• mice expressing highly elevated TSH levels have the most severely affected throid glands; size of thyroid glands is reduced to about half the diameter of control thyroid glands

homeostasis/metabolism

increased circulating thyroid-stimulating hormone level ( J:111027 )

• mean serum TSH levels are higher than in Titf1^tm1Shk/ Titf1^tm2Shk mice or Titf1^tm2Shk homozygous mice but statistical significance was not obtained

• extremely high TSH serum levels are sporadically observed

neoplasm

increased adenoma incidence ( J:111027 )

• small follicles between normal and atrophic/degenerative follicles occasionally form nodular lesions considered to be follicular adenoma