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Pituitary gland and sella turcica in human trisomy 18 fetuses
I Kjaer1, J W Keeling, I Reintoft
1Department of Orthodontics, School of Dentistry, University of Copenhagen, Denmark.
Insights
Trisomy 18 fetuses show abnormal pituitary gland development and malformed sellas. This suggests potential cytoskeletal changes in the pituitary placode, impacting endocrine function in congenital malformations.
Area of Science:
- Developmental Biology
- Genetics
- Endocrinology
Background:
- Congenital malformations often involve endocrine disorders.
- The sella turcica/pituitary gland complex is crucial for endocrine function.
- Trisomy 18 (Edwards syndrome) is a genetic disorder associated with multiple anomalies.
Purpose of the Study:
- To investigate the phenotypic characteristics of the sella turcica/pituitary gland complex in human fetuses with trisomy 18.
- To compare these findings with normal fetal development.
Main Methods:
- Histological and immunohistochemical analysis (keratin wide spectrum [KWS], thyroid-stimulating hormone [TSH], neurophysin [Nph]) of pituitary glands from 14 trisomy 18 fetuses and controls.
- Radiographic examination of the sella turcica and cranial base.
Main Results:
- All trisomy 18 fetuses had TSH-positive adenopituitary tissue in the sella and pharynx; neurohypophysis was normally located.
- Adenohypophyseal tissue in trisomy 18 fetuses showed altered KWS staining (faint or negative) compared to controls.
- Malformed sella turcica and, in some cases, broad craniopharyngeal canals were observed in all trisomy 18 fetuses.
Conclusions:
- Trisomy 18 is associated with distinct phenotypic alterations in the sella turcica/pituitary gland complex.
- Altered KWS staining suggests potential cytoskeletal abnormalities in the pituitary placode during trisomy 18 development.
- Systematic charting of this region in various genotypes is recommended for understanding endocrine dysfunction in congenital malformations.
Abstract:
The purpose of this study was to elucidate the phenotypic conditions in the sella turcica/pituitary gland complex in human trisomy 18 fetuses. Fourteen human fetuses with gestational ages from 12 to 39 weeks were included in the study. Normal fetuses at corresponding ages were used as controls. Whole body and special radiographic examination was undertaken before the midsagittal cranial base block, including the pituitary gland, was excised and analyzed histologically and immunohistochemically (keratin wide spectrum [KWS], thyroid-stimulating hormone [TSH], and neurophysin [Nph]). In all trisomy 18 fetuses, TSH-positive adenopituitary tissue was present in the sella and in greater or lesser amounts pharyngeally. The neurohypophysis was Nph-positive and located normally in the sella turcica. The adenohypophyseal tissue reacted either KWS-faint or KWS-negative, whereas KWS-positive reaction occurs in normal fetuses. This circumstance might suggest an altered cytoskeletal structure of the surface ectoderm in the pituitary placode in trisomy 18. The sella turcica was malformed in all the fetuses. Very broad craniopharyngeal canals were observed in some of the fetuses. Because endocrine disorders occur in many congenital malformations, it is essential in future studies to chart the sella turcica/pituitary gland region systematically in different genotypes.