Question 1 (10 marks): 1. John has Mendelio disease, a rare genetic disorder of the eye that is
characterized by a defect in the iris and reduced visual acuity. Mendelio disease is caused by a
small number of different mutations in the MNDL gene on chromosome 2 , that cause the MNDL
protein (a transcription factor) to be stuck in the activated, or "ON" state. John's father and his
father's sister (John's aunt) both have Mendelio disease, as did his paternal grandmother. John's
mother, two sisters, paternal grandfather, and maternal grandparents are unaffected. John meets
Jane, who also has Mendelio disease, at a support group for the disease. They fall in love and
want to start a family, but when they try to have children they have two pregnancy losses of
fetuses who both had underdeveloped brains and lacked eyes. They seek genetic counselling for
advice.Note: disease and gene names are made up for the purpose of this assignment. A. Draw a
pedigree for this family. Number all generations and individuals and identify John & Jane by name.
B. What is the most likely mode of inheritance for Mendelio disease? Explain. C. What is the most
likely molecular basis of the disease recessive loss of function, haploinsufficiency,
dominantnegative, or gain of function? Explain. D. Explain the likely cause of the pregnancy losses
experienced by John and Jane. E. If John and Jane are able to have a child that survives to birth,
what are the chances that this child will not have Mendelio disease? Explain/show your rationale..
Question 1 10 marks 1 John has Mendelio disease a rare .pdf
1. Question 1 (10 marks): 1. John has Mendelio disease, a rare genetic disorder of the eye that is
characterized by a defect in the iris and reduced visual acuity. Mendelio disease is caused by a
small number of different mutations in the MNDL gene on chromosome 2 , that cause the MNDL
protein (a transcription factor) to be stuck in the activated, or "ON" state. John's father and his
father's sister (John's aunt) both have Mendelio disease, as did his paternal grandmother. John's
mother, two sisters, paternal grandfather, and maternal grandparents are unaffected. John meets
Jane, who also has Mendelio disease, at a support group for the disease. They fall in love and
want to start a family, but when they try to have children they have two pregnancy losses of
fetuses who both had underdeveloped brains and lacked eyes. They seek genetic counselling for
advice.Note: disease and gene names are made up for the purpose of this assignment. A. Draw a
pedigree for this family. Number all generations and individuals and identify John & Jane by name.
B. What is the most likely mode of inheritance for Mendelio disease? Explain. C. What is the most
likely molecular basis of the disease recessive loss of function, haploinsufficiency,
dominantnegative, or gain of function? Explain. D. Explain the likely cause of the pregnancy losses
experienced by John and Jane. E. If John and Jane are able to have a child that survives to birth,
what are the chances that this child will not have Mendelio disease? Explain/show your rationale.
