Developmental Psychology

Achieve Test Prep: Developmental Psychology

• Huntington’s disease: a dominant disease with an onset in the mid-thirties. Huntington’s is a fatal neuromuscular degenerative disease. • Kleinfelter’s syndrome: Kleinfelter’s syndrome is a sex-linked chromosomal abnormality, causing the individual to have an extra X chromosome (XXY). Males are usually afflicted, rendering them infertile and with a degree of mental retardation. This syndrome is often difficult to diagnose, thus leading to misdiagnosis. Fragile X syndrome: As implied by the name, the X chromosome is ‘breakable’ and pieces can ‘fall off’. Fragile X is not a sex-linked abnormality and the severity depends on how much of the chromosome is missing. Typical symptoms include: mental retardation, large head, and large ears. • Turner’s syndrome: Turner’s is typical to females and presents when a female has only one X chromosome. Individuals with this abnormality usually have learning disabilities and are infertile. In addition, secondary sex characteristics rarely develop and many individuals have a ‘webbed’ neck. • Other sex-linked abnormalities: Many sex-linked abnormalities are linked to having an extra sex chromosome. With each addition of a sex chromosome (typically the X chromosome), an increased risk of medical, mental, and learning issues occurs. Due to the advance of science, many genetic abnormalities can be detected. Such detection can extend to individuals who are carriers. If a screening comes back positive for a genetic disease, genetic counseling is typically provided to pregnant women and spouses. Genetics of each parent are an obvious contribution the likelihood of genetic disease occurrence. Another important contribution to the likelihood of occurrence is the age of the mother at conception. The older a woman is when she conceives, the likelihood of genetic abnormalities present in her offspring increases.

Prenatal Development:

There are three stages to prenatal development: • Germinal Stage: o First 14 days

o Zygote travels down the fallopian tube and implants into the uterine wall o Zygote divides and differentiates, thus becoming more specialized

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