# Mitochondrial Disease- ABMG Case Examples

Term
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A molecular genetics laboratory informs you that an infant boy that you have evaluated with probable mitochondrial disease has a single mtDNA deletion. Of the following choices, what is the most appropriate approach regarding genetic counseling:

A. The recurrence risk is negligible for single mtDNA deletions.
B. The potential presence of a duplication must be addressed first before the recurrence risk can be stated.
C. Autosomal recessive or dominant inheritance is present.
D. Any inheritance pattern is possible in mitochondrial disease in general, and in this case in particular.
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Terms in this set (50)
A molecular genetics laboratory informs you that an infant boy that you have evaluated with probable mitochondrial disease has a single mtDNA deletion. Of the following choices, what is the most appropriate approach regarding genetic counseling:

A. The recurrence risk is negligible for single mtDNA deletions.
B. The potential presence of a duplication must be addressed first before the recurrence risk can be stated.
C. Autosomal recessive or dominant inheritance is present.
D. Any inheritance pattern is possible in mitochondrial disease in general, and in this case in particular.
A molecular genetics laboratory informs you that an infant boy that you have evaluated with probable mitochondrial disease has multiple mtDNA deletions. Of the following choices, what is the most appropriate approach regarding genetic counseling:

A. The recurrence risk is negligible for mtDNA deletions.
B. The potential presence of a duplication must be addressed first before the recurrence risk can be stated.
C. Autosomal recessive or dominant inheritance is present
D. Any inheritance pattern is possible in mitochondrial disease in general, and in this case in particular.
Which of the following diseases can present with lactic acidosis and neuromuscular disease:

A. Which of the following diseases can present with lactic acidosis and neuromuscular disease:
mtDNA mutations
B. Nuclear-encoded subunits of the electron transport chain
C. Pyruvate dehydrogenase complex deficiency
D. A and B above
E. All of the above
A newborn male presents with severe lactic acidosis and congenital malformations of the brain and kidneys. A
maternal half brother died of a very similar illness. Among the
following, which is the most likely diagnosis:

A. MELAS
B. Medium chain acyl coenzyme A dehydrogenase (MCAD) deficiency
C. Leigh disease
D. Fumarase deficiency (a Krebs cycle defect)
E. Pyruvate dehydrogenase complex (PDHC) deficiency
A 3 year old girl developed a cough and vomiting. Her 2 brothers recently suffered from the same symptoms. On the third day she became lethargic with rapid progression to coma. Hypoglycemia was noted, and the child made a full and rapid recovery upon resuscitative efforts in an emergency department.
Myopathy is absent. There is no significant past medical history, and the neurological examination and developmental milestones were normal. Among the following, the most likely diagnosis is:

A. Pyruvate dehydrogenase complex (PDHC) deficiency
B. MELAS
C. Medium chain acyl coenzyme A dehydrogenase (MCAD) deficiency
D. Long chain 3-hydroxyl acyl coenzyme A dehydrogenase (LCHAD) deficiency
E. Kearns-Sayre syndrome (KSS)
A 1 year old girl developed a cough and vomiting. Her 2 brothers recently suffered from the same symptoms, which have since resolved. On the third day, the patient became lethargic with rapid progression to coma.
Hypoglycemia was noted, and she made a full and rapid recovery upon resuscitative efforts in an emergency department. Hypotonia, muscle weakness and cardiomyopathy are present, but there is no past history of myopathy. Developmental milestones were normal. Among the following, the most likely diagnosis is:

A. Pyruvate dehydrogenase complex (PDHC) deficiency
B. MELAS
C. Medium chain acyl coenzyme A dehydrogenase (MCAD) deficiency
D. Long chain 3-hydroxyl acyl coenzyme A dehydrogenase (LCHAD) deficiency
E. Kearns-Sayre syndrome (KSS)
A brother and sister presented in early infancy with moderate
developmental delay and a severe seizure disorder. No family members are affected. Muscle biopsy in the boy
supports the presence of a mitochondrial disorder. The recurrence risk in future siblings is most likely:

A. 25%
B. 50%
C. Undetermined, yet likely to be very high
D. Cannot determine from this information.
A boy presents in early infancy with developmental delay and a severe seizure disorder, while his sister presents at age 10 years with a cardiomyopathy. The mother suffers from migraine headaches. Muscle biopsy in the boy supports the presence of a mitochondrial disorder. The recurrence risk in future siblings is most likely:

A. 25%
B. 50%
C. Undetermined, yet likely to be very high
D. Cannot determine from this information.