MMDS4

Multiple Mitochondrial Dysfunctions Syndrome 4

Clinical Characteristics
Ocular Features: 

Optic atrophy is the sole ocular sign reported.

Systemic Features: 

Patients have the onset of severe, unrelenting neuroregression by 6 months of age.  They never achieve normal milestones and eventually regress to a vegetative state.  No dysmorphic features are present.  Muscle spasticity has been reported.  Brain imaging shows multiple nonspecific signal anomalies throughout.  Biopsy of skeletal muscle shows atrophic and angulated fibers.

Mitochondrial DNA copy numbers are decreased as is the activity of respiratory complex I. 

Genetics

Homozygous mutations in the ISCA2 gene (14q24.3) segregates with the disease in the 5 reported families.  This gene codes for an essential component of mitochondrial assembly and function.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment is known and death often occurs before the age of 5 years.

References
Article Title: 

ISCA2 mutation causes infantile neurodegenerative mitochondrial disorder

Al-Hassnan ZN, Al-Dosary M, Alfadhel M, Faqeih EA, Alsagob M, Kenana R, Almass R, Al-Harazi OS, Al-Hindi H, Malibari OI, Almutari FB, Tulbah S, Alhadeq F, Al-Sheddi T, Alamro R, AlAsmari A, Almuntashri M, Alshaalan H, Al-Mohanna FA, Colak D, Kaya N. ISCA2 mutation causes infantile neurodegenerative mitochondrial disorder. J Med Genet. 2015 Mar;52(3):186-94.

PubMed ID: 
25539947
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