Mitochondrial disorders

2.  Unlike nuclear genes, which are inherited from both
parents, mitochondrial genes are inherited only from the
mother.
• In mammals, 99.99% of
mitochondrial DNA
(mtDNA) is inherited from
the mother.
• This is because the sperm
carries its mitochondria
around a portion of its tail
and has only about 100
mitochondria compared
to 100,000 in the oocyte.

3. Encephalomyopathy with Lactic Acidosis and Stroke-like Episodes

4. • It is the most common inherited mitochondrial disease
• Clinical Features: Strokes, myopathy, muscle twitching,
dementia (memory loss desease), and deafness
• To a lesser extent: vomiting, migraine(severe) like headaches,
diabetes, droopy eyelids, muscle weakness, and short stature
• Presentation of the disease occurs with the first stroke-like
episode (usually 14-15 years of age)
• This is a progressive disorder with a high mortality rate

5. • Abnormal mitochondria do not metabolize pyruvate
• Excess pyruvate is reduced to lactic acid which accumulates in blood
and other fluids
• Large abnormal mitochondria form in the walls of small arteries and
capillaries in the brain and muscles
How does MELAS work?
What causes MELAS?
• There are at least 6 different point mutations associated with MELAS
• 80% of cases have a A to G point mutation in the tRNA gene at
position 3243
• 7.5% of cases have aT to C point mutation in the tRNA gene at
position 3271

7. • All of these mutations are heteroplasmic
• Heteroplasmic : within a single cell, there is a mixture of mitochondria, some
containing mutant DNA and some containing normal DNA
Further Details
Alex received his angel
wings on Oct. 4, 2014 and
battled MELAS for 11 years.

8. What is MERRF ??
Classic Features of MERRF ..

9. Symptoms of MERRF
Short Stature
Lactic Acidosis – Elevated lactic acid level in the blood.
Cardiac Defects
Exercise Intolerance –
Dementia – Memory loss disease.
Speech Impairment - The condition of being unable to Speech as a
consequence of physical or mental unfitness
Eye Abnormalities
Hearing Loss

10. Causes of MERRF
his mutation disrupts a mitochondrial gene
for tRNA-Lys and so disrupts the synthesis of
proteins essential for Oxidative
Phosphorylation
Treatment of MERRF
Coenzyme Q10 L-Carnitine

11. What is Renal Oncocytoma ??
 A renal oncocytoma is a tumour of the kidney made up of
oncocytes, a special kind of cell

12. Description
discovered incidentally (by chance) on a tomography or
ultrasound of the abdomen
Hematuria -The presence of blood in the urine
Flank Pain – Region Between hip and ribs
Abdominal Mass
These tumors are basically densely packed cells with
mitochondria, which show morphologic differences from
those in normal cells
Symptoms
It is characterized by benign tumour that occurs in different
body parts but specially in kidneys

13. Treatment
Renal oncocytoma is considered benign, cured by
nephrectomyis characterized by benign tumour that occurs in
different body parts but specially in kidneys
Nephrectomy – is the surgical removal of a kidney
The End 