A novel mutation in the SCO2 gene in a neonate with early-onset cardioencephalomyopathy.
Mutations in the SCO2 gene [SCO cytochrome oxidase deficient homolog 2 (yeast)] causing cytochrome c oxidase deficiency have been reported in at least in 26 patients with fatal infantile cardioencephalomyopathy. Mutation 1541G > A affecting protein stability is associated with the majority of cases, and the other 11 described mutations have more serious deleterious structural consequences for the protein product. Reported here is a novel case caused by compound heterozygosity of SCO2. The child presented at the age of 3 weeks with failure-to-thrive, muscular hypotonia, hypertrophic cardiomyopathy, and lactic acidemia. Leigh syndrome was diagnosed based on magnetic resonance imaging findings. Immunohistochemical and enzymatic investigations on muscle indicated totally absent cytochrome c oxidase activity. Both parents had mild mental retardation. Sequence analysis in the patient and in his parents revealed heterozygous mutation c.418G > A in exon 2 inherited from the father and maternally inherited heterozygous insertion of 19bp at position 17 in the coding region of the SCO2 gene. Respiratory chain enzyme activity measurements indicated normal activity in both parents, although the mother's cytochrome c oxidase activity was lower. This gene may be involved in the etiology of the mother's mental retardation.
Tallinn Children's Hospital, Tallinn, Estonia.
Kairit
K
Joost
Richard
R
Rodenburg
Andres
A
Piirsoo
Bert
B
van den Heuvel
Riina
R
Zordania
Katrin
K
Ounap
D000367:Age Factors; D001925:Brain Damage, Chronic / Q000150:complications* / Q000235:genetics*; D009202:Cardiomyopathies / Q000150:complications* / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics*; D004252:DNA Mutational Analysis; D005183:Failure to Thrive / Q000175:diagnosis / Q000209:etiology; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D024101:Mitochondrial Proteins / Q000235:genetics*; D018832:Molecular Chaperones; D016254:Mutagenesis, Insertional / Q000235:genetics; D017354:Point Mutation / Q000235:genetics*
D002352:Carrier Proteins; D024101:Mitochondrial Proteins; D018832:Molecular Chaperones; C400285:SCO2 protein, human