Steroidogenesis delta 5 pathway

The fetal adrenal cortex lacks expression of the enzyme early on, thus mineralocorticoids (. aldosterone ) and glucocorticoids (. cortisol ) cannot be synthesized. This is significant because cortisol induces type II pneumocytes of the lungs to synthesize and secrete pulmonary surfactant ; without pulmonary surfactant to reduce the alveolar surface tension , premature neonates may die of neonatal respiratory distress syndrome . If delivery is unavoidable (. because of placental abruption , or pre-eclampsia / HELLP syndrome ), then glucocorticoids (. cortisol) can be administered.

The OECD Guidelines for the Testing of Chemicals is a collection of about 150 of the most relevant internationally agreed testing methods used by government, industry and independent laboratories to identify and characterise potential hazards of chemicals. They are a set of tools for professionals, used primarily in regulatory safety testing and subsequent chemical and chemical product notification, chemical registration and in chemical evaluation. They can also be used for the selection and ranking of candidate chemicals during the development of new chemicals and products and in toxicology research. This group of tests covers health effects.

In a larger series of 118 unrelated cases of Apert syndrome studied in Oxford, Moloney et al. (1996) found that 74 had the 934C-G mutation and 44 had the 937C-G mutation. Combined with the cases reported by Park et al. (1995) , the total experience indicated that 108 of 166 cases (65%) were of the 934C-G type, 57 of 166 cases (34%) were of the 937C-G type, and 1 case observed by Park et al. (1995) was of unknown mutational basis. Wilkie (1996) observed paternal age effect with both Apert mutations in 54 informative families; the mutation was of paternal origin in all cases. Limb malformation seemed to be more severe in the 937C-G mutation; cleft palate was more often present, and craniofacial abnormality was in general more severe with the 934C-G mutation ( Wilkie, 1996 ). Indeed, the severe craniofacial abnormality and cleft palate in association with milder involvement of the hands gave rise to the designation of Vogt cephalodactyly or Apert-Crouzon disease for the condition in the cases described by Vogt (1933) combining the hand and foot malformations characteristic of Apert disease with the facial characteristics of Crouzon disease; see 101200 .

Steroidogenesis delta 5 pathway

steroidogenesis delta 5 pathway

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