Holoprosencephaly Is a Highly Variable Condition in Mammals, Including Humans

question 27

Multiple Choice

Holoprosencephaly is a highly variable condition in mammals, including humans. Its effects range from an absence of brain areas, mid-face disorders, and cyclopia to slight dental abnormalities. One form, HPE3, is caused by Shh mutations. Familial cases are inherited as dominants. Which of the following do you expect?

• A)HPE3 is actually a multigene complex.
• B)Each type of malformation is due to a different HPE3 allele.
• C)HPE3 expression is modified by genetic background.
• D)HPE3 individuals also share a common environmental exposure.
• E)All mutations in Shh that result in HPE3 are due to frameshifts.

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Definitions:

Urie Bronfenbrenner

A psychologist famous for developing the Ecological Systems Theory to explain how the inherent qualities of a child and his environment interact to influence how he will grow and develop.

Child Development

The biological, psychological, and emotional changes that occur in humans from birth to the end of adolescence, as the individual progresses from dependency to increasing autonomy.

Unconscious Conflicts

Deep-seated, often repressed conflicts within a person's mind, which can affect behaviors and emotions without the person being fully aware of them.

Ecological Theory

A framework suggesting that individual development is influenced by different types of environmental systems, from immediate surroundings to broader societal contexts.