While many leopard frog populations have survived and returned to near normal levels, the leopard frogs of the Upper Midwest have a high incidence of developmental malformations.
Some afflictions that may affect the uterus include infections; benign and malignant tumours; malformations, such as a double uterus; and prolapse, in which part of the uterus becomes displaced and protrudes from the vaginal opening.
Finally, there are probable deleterious effects of radiation in producing congenital malformations, certain leukemias, and possibly some genetic disorders (see radiation: Biologic effects of ionizing radiation).
Heavier consumption of alcohol, more than 60 millilitres per day, by a pregnant woman can result in malformations of the fetal brain and in spontaneous abortions.
Programmed cell death plays an important role in vertebrate ontogeny (embryological development) and teratogenesis (the production of malformations), as well as in the spectacular metamorphoses that affect tadpoles or caterpillars.
Cyclopian malformations with a single median eye occur rarely in man and other animals.
Such double malformations probably arise following the less complete separation of the halves of the early embryo or partial separation at later stages.
The disorder is accompanied by severe spinal defects and often brain and face malformations, such as anencephaly and cyclopia.
The most common congenital malformations that block the normal drainage of CSF affect the aqueduct of Sylvius, a canal that connects the third and fourth ventricles in the brain to the central canal of the spinal cord.
Infants born with this disorder have profound mental retardation and severe developmental malformations that include a small head, a cleft palate and lip, tiny eyes and eye openings, extra digits on hands and feet (polydactyly), clenched fingers, central nervous system abnormalities, and defects in many internal organs.
Other causes of spontaneous subarachnoid hemorrhage include arteriovenous malformations, anticoagulation therapy, and the use of certain illicit drugs such as cocaine.
