Case No. 0621-IP Patient Name: Emily S. Age: 25 This healthy, well-nourished woman presented for genetic counseling a referral from her obstetrician. She was accompanied by her husband, Dan, aged 26 years. The couple has been married for two years. Emily answered all questions quickly and appropriately. Emily states that she is worried about having children due to a family history of incontinentia pigmenti (IP). Her sister is affected with the disease and experienced several miscarriages (see History below). Incontinentia pigmenti is a congenital skin condition usually associated with skeletal and other malformations. In the fully developed disease, the skin shows swirling patterns of melanin pigmentation, especially in the trunk, giving a marbled appearance. The pigmentation fades gradually and usually disappears completely by age 20. Associated medical problems with IP include deformities of the vessels of the eye (retina) and brain, however not all persons with IP are affected. Emily had one prior pregnancy with a previous boyfriend. The pregnancy was terminated at 10 weeks gestation; gender of the fetus was not determined. Emily has had no pregnancies with her present husband, who is unaffected and has no family history of the disease. Emily has one sister, 29 years old, who is affected with IP. The sister has had three miscarriages, all within 14-16 weeks gestation (a normal pregnancy ends with birth at 40 weeks gestation). All of the miscarried fetuses were male. The sisters husband (31 years) is unaffected with IP and has no family history of the disease. One unaffected full-brother, 23 years old. He is unmarried and has no children. Mother, aged 51, has IP; father, aged 52, is unaffected. Emilys maternal aunt, Jennifer, aged 54, has the disease; she is married to an unaffected man, aged 55 who has no family history of the disease. She has had two miscarriages (fetal ages and genders unknown) and has one unaffected daughter (Emilys cousin, Kathy). Kathy has two unaffected sons. One maternal aunt and one maternal uncle are unaffected. Neither of them has children. Emilys grandmother, deceased at age 75 had IP. She reported a miscarriage in a letter to a family member, but details are lacking. Emilys grandfather, deceased at age 77, was unaffected by the disease. Draw a pedigree. What is the mode of inheritance for IP? Specific Questions: 1. What is the probability Emilys children expressing incontinentia pigment? Does the sex of the child have any relevance to what you would tell her? 2. What is the probability that Emilys sisters children will be affected with IP? 3. Explain how the Pedigree does or does not allow you to eliminate other possible modes of inheritance..

1. Case No. 0621-IP Patient Name: Emily S. Age: 25
This healthy, well-nourished woman presented for genetic counseling a referral from her
obstetrician. She was accompanied by her husband, Dan, aged 26 years. The couple has been
married for two years. Emily answered all questions quickly and appropriately. Emily states that
she is worried about having children due to a family history of incontinentia pigmenti (IP). Her
sister is affected with the disease and experienced several miscarriages (see History below).
Incontinentia pigmenti is a congenital skin condition usually associated with skeletal and other
malformations. In the fully developed disease, the skin shows swirling patterns of melanin
pigmentation, especially in the trunk, giving a marbled appearance. The pigmentation fades
gradually and usually disappears completely by age 20. Associated medical problems with IP
include deformities of the vessels of the eye (retina) and brain, however not all persons with IP are
affected. Emily had one prior pregnancy with a previous boyfriend. The pregnancy was terminated
at 10 weeks gestation; gender of the fetus was not determined. Emily has had no pregnancies with
her present husband, who is unaffected and has no family history of the disease. Emily has one
sister, 29 years old, who is affected with IP. The sister has had three miscarriages, all within 14-16
weeks gestation (a normal pregnancy ends with birth at 40 weeks gestation). All of the miscarried
fetuses were male. The sisters husband (31 years) is unaffected with IP and has no family history
of the disease. One unaffected full-brother, 23 years old. He is unmarried and has no children.
Mother, aged 51, has IP; father, aged 52, is unaffected. Emilys maternal aunt, Jennifer, aged 54,
has the disease; she is married to an unaffected man, aged 55 who has no family history of the
disease. She has had two miscarriages (fetal ages and genders unknown) and has one unaffected
daughter (Emilys cousin, Kathy). Kathy has two unaffected sons. One maternal aunt and one
maternal uncle are unaffected. Neither of them has children. Emilys grandmother, deceased at
age 75 had IP. She reported a miscarriage in a letter to a family member, but details are lacking.
Emilys grandfather, deceased at age 77, was unaffected by the disease.
Draw a pedigree. What is the mode of inheritance for IP?
Specific Questions:
1. What is the probability Emilys children expressing incontinentia pigment? Does the sex of the
child have any relevance to what you would tell her?
2. What is the probability that Emilys sisters children will be affected with IP?
3. Explain how the Pedigree does or does not allow you to eliminate other possible modes of
inheritance.