Question

A. Read the scenario below: A Sickeningly Sweet Baby Boy: A Case Study on Autosomal Recessive Inheritance by Jacqueline Washington, Department of Biology and Chemistry, Nyack College, Nyack, NY Anne Zayaitz, Department of Biology, Kutztown University, Kutztown, PA Scenario: Emma and Jacob Miller were so excited at the birth of their baby Matthew. Both the pregnancy and delivery had been uneventful. But in the back of their minds, they really were worried because their first child, Samuel, died at the age of nine days. By the fifth day after birth, Matthew began to have trouble nursing and by the seventh day he had completely stopped feeding. Emma and Jacob were frantic because it seemed to them that Matthew might also die. "What is going on with our family? Another sick baby?" Jacob thought to himself. Emma and Jacob rushed him to the emergency room. Although Mathew’s limbs were rigid and he had had a seizure, the examination showed no infection and his x-rays were normal. The doctor also did routine lab tests on his blood and urine. "Doctor, do you think that this funny smell in Matthew’s diapers has anything to do with his problem?" Emma asked. "I brought one along so that you could smell it too." Matthew’s urine did have a sweet, maple syrup smell and lab results revealed elevated levels of the branched chain amino acids valine, isoleucine, and leucine. Skin biopsies from the baby and his parents were taken and cultured. The ability of the cultured skin fibroblasts to metabolize these three amino acids was determined. While his parents’ enzyme activity levels were nearly normal, Matthew’s was 200 times lower than normal. "Given the medical information and the smell of the urine, Matthew has Maple Syrup Urine Disease (msud)," reported Dr. Morton of the Clinic for Special Children. "He will not be able to breast feed or drink regular formula. What is really important is that Matthew eats a low protein diet. This diet must continue for the rest of his life or else the amino acids will accumulate in the body creating a situation that leads to brain swelling, neurological damage, and death. In spite of dietary intervention, the disease may cause several complications, the most notable being mental retardation." A discussion with Emma’s grandmother revealed that Emma’s mother had two sisters who died in their first year of life; no one knew why. Jacob’s father had a brother who died at seven months of age from unknown causes. Could the gene for msud run in both of their families? msud is due to a recessive gene. For an individual to be affected, he or she would need to inherit a defective nonworking copy from each parent. The individual would then be described as being homozygous recessive.

A. Read the scenario below:

A Sickeningly Sweet Baby Boy: A Case Study on Autosomal Recessive Inheritance
by Jacqueline Washington, Department of Biology and Chemistry, Nyack College, Nyack, NY
Anne Zayaitz, Department of Biology, Kutztown University, Kutztown, PA

Scenario: Emma and Jacob Miller were so excited at the birth of their baby Matthew.
Both the pregnancy and delivery had been uneventful. But in the back of their minds, they really were worried because their first child, Samuel, died at the age of nine days. By the fifth day after birth, Matthew began to have trouble nursing and by the seventh day he had completely stopped feeding. Emma and Jacob were frantic because it seemed to them that Matthew might also die.

"What is going on with our family? Another sick baby?" Jacob thought to himself.

Emma and Jacob rushed him to the emergency room. Although Mathew’s limbs were rigid and he had had a seizure, the examination showed no infection and his x-rays were normal. The doctor also did routine lab tests on his blood and urine.

"Doctor, do you think that this funny smell in Matthew’s diapers has anything to do with his problem?" Emma asked. "I brought one along so that you could smell it too."

Matthew’s urine did have a sweet, maple syrup smell and lab results revealed elevated levels of the branched chain amino acids valine, isoleucine, and leucine. Skin biopsies from the baby and his parents were taken and cultured. The ability of the cultured skin fibroblasts to metabolize these three amino acids was determined. While his parents’ enzyme activity levels were nearly normal, Matthew’s was 200 times lower than normal.

"Given the medical information and the smell of the urine, Matthew has Maple Syrup Urine Disease (msud)," reported Dr. Morton of the Clinic for Special Children. "He will not be able to breast feed or drink regular formula. What is really important is that Matthew eats a low protein diet. This diet must continue for the rest of his life or else the amino acids will accumulate in the body creating a situation that leads to brain swelling, neurological damage, and death. In spite of dietary intervention, the disease may cause several complications, the most notable being mental retardation."

A discussion with Emma’s grandmother revealed that Emma’s mother had two sisters who died in their first year of life; no one knew why. Jacob’s father had a brother who died at seven months of age from unknown causes. Could the gene for msud run in both of their families?

msud is due to a recessive gene. For an individual to be affected, he or she would need to inherit a defective nonworking copy from each parent. The individual would then be described as being homozygous recessive.

A. Read the scenario below:

A Sickeningly Sweet Baby Boy: A Case Study on Autosomal Recessive Inheritance
by Jacqueline Washington, Department of Biology and Chemistry, Nyack College, Nyack, NY
Anne Zayaitz, Department of Biology, Kutztown University, Kutztown, PA

Scenario: Emma and Jacob Miller were so excited at the birth of their baby Matthew.
Both the pregnancy and delivery had been uneventful. But in the back of their minds, they really were worried because their first child, Samuel, died at the age of nine days. By the fifth day after birth, Matthew began to have trouble nursing and by the seventh day he had completely stopped feeding. Emma and Jacob were frantic because it seemed to them that Matthew might also die.

"What is going on with our family? Another sick baby?" Jacob thought to himself.

Emma and Jacob rushed him to the emergency room. Although Mathew’s limbs were rigid and he had had a seizure, the examination showed no infection and his x-rays were normal. The doctor also did routine lab tests on his blood and urine.

"Doctor, do you think that this funny smell in Matthew’s diapers has anything to do with his problem?" Emma asked. "I brought one along so that you could smell it too."

Matthew’s urine did have a sweet, maple syrup smell and lab results revealed elevated levels of the branched chain amino acids valine, isoleucine, and leucine. Skin biopsies from the baby and his parents were taken and cultured. The ability of the cultured skin fibroblasts to metabolize these three amino acids was determined. While his parents’ enzyme activity levels were nearly normal, Matthew’s was 200 times lower than normal.

"Given the medical information and the smell of the urine, Matthew has Maple Syrup Urine Disease (msud)," reported Dr. Morton of the Clinic for Special Children. "He will not be able to breast feed or drink regular formula. What is really important is that Matthew eats a low protein diet. This diet must continue for the rest of his life or else the amino acids will accumulate in the body creating a situation that leads to brain swelling, neurological damage, and death. In spite of dietary intervention, the disease may cause several complications, the most notable being mental retardation."

A discussion with Emma’s grandmother revealed that Emma’s mother had two sisters who died in their first year of life; no one knew why. Jacob’s father had a brother who died at seven months of age from unknown causes. Could the gene for msud run in both of their families?

msud is due to a recessive gene. For an individual to be affected, he or she would need to inherit a defective nonworking copy from each parent. The individual would then be described as being homozygous recessive.

Added by Antonio V.

Biology for AP Courses

Julianne Zedalis, John Eggebrecht

Instant Answer

Solved by Expert Adi S

04/30/2022

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The case study presents a newborn, Matthew, who has been diagnosed with Maple Syrup Urine Disease (MSUD), a condition characterized by the body's inability to break down certain amino acids, leading to a sweet-smelling urine and severe health issues. Both of Show more…

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A. Read the scenario below: A Sickeningly Sweet Baby Boy: A Case Study on Autosomal Recessive Inheritance by Jacqueline Washington, Department of Biology and Chemistry, Nyack College, Nyack, NY Anne Zayaitz, Department of Biology, Kutztown University, Kutztown, PA Scenario: Emma and Jacob Miller were so excited at the birth of their baby Matthew. Both the pregnancy and delivery had been uneventful. But in the back of their minds, they really were worried because their first child, Samuel, died at the age of nine days. By the fifth day after birth, Matthew began to have trouble nursing and by the seventh day he had completely stopped feeding. Emma and Jacob were frantic because it seemed to them that Matthew might also die. "What is going on with our family? Another sick baby?" Jacob thought to himself. Emma and Jacob rushed him to the emergency room. Although Mathew’s limbs were rigid and he had had a seizure, the examination showed no infection and his x-rays were normal. The doctor also did routine lab tests on his blood and urine. "Doctor, do you think that this funny smell in Matthew’s diapers has anything to do with his problem?" Emma asked. "I brought one along so that you could smell it too." Matthew’s urine did have a sweet, maple syrup smell and lab results revealed elevated levels of the branched chain amino acids valine, isoleucine, and leucine. Skin biopsies from the baby and his parents were taken and cultured. The ability of the cultured skin fibroblasts to metabolize these three amino acids was determined. While his parents’ enzyme activity levels were nearly normal, Matthew’s was 200 times lower than normal. "Given the medical information and the smell of the urine, Matthew has Maple Syrup Urine Disease (msud)," reported Dr. Morton of the Clinic for Special Children. "He will not be able to breast feed or drink regular formula. What is really important is that Matthew eats a low protein diet. This diet must continue for the rest of his life or else the amino acids will accumulate in the body creating a situation that leads to brain swelling, neurological damage, and death. In spite of dietary intervention, the disease may cause several complications, the most notable being mental retardation." A discussion with Emma’s grandmother revealed that Emma’s mother had two sisters who died in their first year of life; no one knew why. Jacob’s father had a brother who died at seven months of age from unknown causes. Could the gene for msud run in both of their families? msud is due to a recessive gene. For an individual to be affected, he or she would need to inherit a defective nonworking copy from each parent. The individual would then be described as being homozygous recessive.