Co segregation of the m.1555A>G mutation in the MT-RNR1 gene and mutations in MT-ATP6 gene in a family with dilated mitochondrial cardiomyopathy and hearing loss: A whole mitochondrial genome screening.

Mitochondrial disease refers to a heterogeneous group of disorders resulting in defective cellular energy production due to dysfunction of the mitochondrial respiratory chain, which is responsible for the generation of most cellular energy. Because cardiac muscles are one of the high energy demanding tissues, mitochondrial cardiomyopathies is one of the most frequent mitochondria disorders. Mitochondrial cardiomyopathy has been associated with several point mutations of mtDNA in both genes encoded mitochondrial proteins and mitochondrial tRNA and rRNA. We reported here the first description of mutations in MT-ATP6 gene in two patients with clinical features of dilated mitochondrial cardiomyopathy. The mutational analysis of the whole mitochondrial DNA revealed the presence of m.1555A>G mutation in MT-RNR1 gene associated to the m.8527A>G (p.M>V) and the m.8392C>T (p.136P>S) variations in the mitochondrial MT-ATP6 gene in patient1 and his family members with variable phenotype including hearing impairment. The second patient with isolated mitochondrial cardiomyopathy presented the m.8605C>T (p.27P>S) mutation in the MT-ATP6 gene. The three mutations p.M1V, p.P27S and p.P136S detected in MT-ATP6 affected well conserved residues of the mitochondrial protein ATPase 6. In addition, the substitution of proline residue at position 27 and 136 effect hydrophobicity and structure flexibility conformation of the protein.

Neonatal lupus erythematosus with congenital heart block in twins.

Background - Neonatal lupus erythematosus is an uncommon acquired autoimmune disease caused by transplacental passage of maternal antibodies SSA/Ro, SSB/La or U1 ribonucleoproteins. The most common clinical manifestations are skin rash, cardiac lesions, thrombocytopenia, anemia and hepatosplenomegaly. Complete congenital heart block is usually irreversible needing a pacemaker implantation in two-thirds of cases. Cases report - We report neonatal lupus erythematosus with complete congenital heart block in twins. Newborns were delivered by caesarean section at week 38 of gestation with a heart rate regular at 70 beats per minute. Both twins and mother were positive for antinuclear, anti-SSA, and anti-SSB antibodies. Twins received single-chamber pacemaker implants at day 12 of life. The evolution was immediately favorable with a heart rate around 110 beats per minute. The follow-up was 2 years. The twins are currently asymptomatic. Conclusion - Complete congenital heart block is the most serious manifestation of the neonatal lupus erythematosus associated with significant morbidity and mortality.

Cholestasis and protein-losing enteropathy secondary to hyperthyroidism in a 6-year-old girl.

Hepatic dysfunctions are not infrequent in patients with hyperthyroidism. These disorders may be related to the effects of the excess thyroid hormone secretion, to the uses of antithyroid drugs, or to the presence of concomitant hepatic diseases. Our aim is to describe the clinical and biochemical features of liver dysfunction related to thyrotoxicosis. We report here a case of a 6-year-old girl who was admitted for jaundice and pruritus as a result of the development of hyperthyroidism due to Graves' disease. On physical examination at admission, she was found to have jaundice and hepatomegaly. Laboratory data show cholestasis and protein-losing enteropathy. Investigations exclude other causes of hepatic disorder. One month after the initiation of antithyroid drug, the patient became euthyroid with improvement in jaundice and pruritus and normalization of hepatic tests and alpha antitrypsine clearance. In conclusion, the diagnosis of hyperthyroidism may be delayed in patients in whom the primary manifestations were pruritus and jaundice. The physician should suspect thyrotoxicosis prior to hepatitis or skin manifestations.