Hepatitis C virus infection in pediatric liver transplantation.

To determine the prevalence of antibodies to hepatitis C virus (HCV) and the short-term evolution of HCV infection in children undergoing orthotopic liver transplantation, we retrospectively studied the sera and medical records of 149 children surviving from 9 months to 5 years after OLT. Fourteen children (9.4%) were found to be positive for anti-HCV with second-generation ELISA and RIBA tests. They were individualized in 2 distinctive groups. In 5 children, anti-HCV was present before OLT, and in 1 patient only HCV RNA was detected at that time. All 6 patients were positive for anti-HCV after OLT. In the other 8 children, anti-HCV and HCV RNA were only detected after OLT and likely reflect infection during or shortly after OLT. The antibody reactivities against the 3 antigens included in the second-generation RIBA test varied in a given patient throughout follow-up and between these 2 groups of children. In all patients, serum transaminase (ALT) activities returned to normal levels when prednisone therapy was lowered and given every other day. These results indicate that the search for HCV infection in these children is necessary in the differential diagnosis of other liver complications in order to avoid excessive immunosuppressive treatment.

Defects in type IIA von Willebrand disease: a cysteine 509 to arginine substitution in the mature von Willebrand factor disrupts a disulphide loop involved in the interaction with platelet glycoprotein Ib-IX.

Type IIA von Willebrand disease (vWD) is characterized by the loss of high and intermediate weight multimers of von Willebrand factor (vWF) from plasma. The 3' end of exon 28 in the vWF gene from four type IIA vWD patients was amplified by the polymerase chain reaction, cloned and sequenced. Sequencing identified two potential missense mutations resulting in the amino acid substitutions Arg 834-->Gln and Glu 875-->Lys in the mature vWF subunit within an area of vWF where mutations in type IIA vWD have been reported. Neither of these amino acid substitutions was found in over 100 normal alleles tested by allele specific oligonucleotide hybridization. A polymorphism (Val 802-->Leu) was identified in another patient. Other areas of exon 28 were analysed by denaturing gradient gel electrophoresis (DGGE) and DNA from one patient demonstrated an irregular DGGE pattern on the 5' end of the exon. Sequencing demonstrated an amino acid substitution of an arginine for cysteine at position 509 adjacent to an area of vWF where defects associated with type IIB vWD have been found. This substitution was not found in 100 normal chromosomes tested by restriction enzyme digestion. The Cys 509-->Arg substitution eliminates an intramolecular disulphide bridge formed by Cys 509 and Cys 695 which is important to maintain the configuration of vWF functional domains that interact with platelet glycoprotein Ib-IX.

Molecular study of von Willebrand disease: identification of potential mutations in patients with type IIA and type IIB.

The defective von Willebrand Factor (vWF) in type IIA von Willebrand disease (vWD) has decreased binding affinity for platelet membrane glycoprotein Ib (GPIb) while in type IIB vWD, the abnormal vWF has increased affinity for this receptor. Segments of exon 28 of the vWF gene were amplified by the polymerase chain reaction and sequenced in two patients with type IIA and two patients with type IIB vWD. One type IIB patient showed an arginine to tryptophan substitution at amino acid residue 543 in the mature vWF and the other patient had a valine to methionine change at residue 553. Including these two new cases, substitutions at residues 543 and 553 now account for more than half of the documented mutations in patients with type IIB vWD. One patient with type IIA vWD showed an isoleucine to threonine change at amino acid 865. This substitution has been reported in another patient with type IIA vWD. The other patient showed a novel proline to serine change at residue 885. The C to T nucleotide transition which causes the amino acid change was not found in over 100 normal chromosomes tested by allele specific oligonucleotide hybridization and was linked to type IIA vWD in the family. This potential mutation is more carboxyterminal in the vWF subunit than other reported mutations in type IIA vWD. It is apparent that mutations associated with type IIA vWD are not as tightly grouped as defects in type IIB vWD, supporting the evidence that the type IIA vWD phenotype is generated by diverse mechanisms.

Ullrich's congenital atonic sclerotic muscular dystrophy. A case report.

A 5-year old girl with Ullrich's atonic-sclerotic muscular dystrophy is reported and 16 previously reported cases are reviewed. The clinical features, in particular proximal contractures, distal hyperextensibility, mild dysmorphism and hyperhidrosis, allow recognition of this subtype of congenital muscular dystrophy, which has no specific pathological characteristics. There is evidence in favour of an autosomal recessive mode of inheritance.