Question

Jack and his wife, Angela (27), have been referred to you by Angela’s gynecologist. Jack, a healthy male, has a family history of anhidrotic ectodermal dysplasia (ED). The couple has one unaffected son, aged 2 years, and are contemplating having a second child.

Ectodermal dysplasia is a disorder characterized by absence of sweat glands and malformed or missing teeth. Some persons having ED also have unusual hair growth patterns and mental retardation. Persons having the disease are at risk of heat-stroke because their bodies are unable to regulate internal temperature.

Family history:

Jack has one unaffected brother, age 26.

Jack’s mother (age 50) is unaffected with no family history of the disease.

Jack’s father, Max, (51) is unaffected. Jack’s father has one brother (49) and
one sister (47), both unaffected. Parents are unaffected. Max’s father has no family history of the disease but his mother has one affected brother and one unaffected sister. The brother, age 45, is unmarried with no children. The unaffected sister, age 42, is married to a man without history of the disease. They have six children: two affected boys, two unaffected boys, and two unaffected daughters.

Angela has one affected brother.

Angela’s father is unaffected. Her father was adopted as baby and doesn’t know his family history.

Angela’s mother, Alice, is of normal appearance and intelligence but has congenitally missing teeth. Alice has one unaffected brother. Alice’s mother is unaffected; no family history of the disease. Alice’s father, John, was affected having missing teeth and absent sweat glands. John’s fraternal twin brother was unaffected. Both of John’s parents were unaffected.

Draw a Pedigree using this information,indicating as many genotypes as possible. What is the probability that Jack is a carrier for ED?

Answer 1

XY Xx xx Oxx XY Xx/ су | СА XY John |xү, Јусу xey 0xy (хX. XY С Пхсу JxY max 100 х'yx* Ori ХУ ХҮ хх/ XY Alice IV Х“Х Jxy Тобт Jack ХУ XX xey Angela v ху X-triked recessive

From the pedigree, the trait appears to be X linked recessive.

For such traits, males cannot be carrier. So, probability that Jack is a carrier is 0.

Please rate high.