Replacement of the Y450 (c234) phenyl ring in the carboxyl-terminal region of coagulation factor IX causes pleiotropic effects on secretion and enzyme activity.

The interplay between impaired protein biosynthesis and/or function caused by missense mutations, particularly in relation to specific protein regions, has been poorly investigated. As model we chose the severe p.Y450C mutation in the carboxyl-terminal region of coagulation factor IX (FIX) and, by expression of a panel of recombinant variants, demonstrated the key role of the tyrosine phenyl group for both FIX secretion and coagulant activity.

Unusual presentation of haemophilia in two paediatric patients.

Haemophilia A is a rare X-linked recessive bleeding disorder caused by deficiency or functional defects in coagulation factor VIII (FVIII). Here, we report two cases of challenging diagnosis of haemophilia A because of unusual presentation. The first case is a 10-month-old female, admitted to our hospital because a neck mass appeared within the previous 24 h, who had a past medical history consistent with recurrent spontaneous haematomas but no family history of bleeding disorders.

Diagnostic potential of hepcidin testing in pediatrics.

Objectives: Hepcidin, a peptide hormone released by hepatocytes into circulation is the main regulator of dietary iron absorption and cellular iron release. Although commercial tests are available, assay harmonization for hepcidin has not been yet reached, making reference intervals and consequent clinical decisions still elusive for each assay and specific population. The aim of this study is to set up hepcidin measurement in pediatric age and to investigate its potential usefulness in the diagnosis and management of iron disorders in children.

Molecular cytogenetic definition of a translocation t(X;15) associated with premature ovarian failure.

Objective: To characterize the breakpoints of a t(X;15) found in a woman with premature ovarian failure (POF).

Design: Case report.

Setting: Molecular and cytogenetics unit in a university-affiliated hospital.

The Italian AICE-Genetics hemophilia A database: results and correlation with clinical phenotype.

Background: The high mutational heterogeneity of hemophilia A is a challenge for the provision of genetic services. We plan to identify the mutation in patients with hemophilia A in order to create a confidential national database of mutations for the optimization of genetic services in Italy.

Design And Methods: The factor VIII gene (F8) was analyzed in 1296 unrelated patients with hemophilia A using screening methods for intron 22 and 1 inversions and rare mutations (denaturing high performance liquid chromatography, conformation sensitive gel electrophoresis) and/or direct sequencing.

Mosaic ring Y chromosome in two normal healthy men with azoospermia.

Objective: To better define by molecular and cytogenetic techniques ring Y chromosomes detected in 2 infertile men.

Design: Case report.

Setting: Molecular genetics/cytogenetics unit in a university hospital.

Exon skipping partially restores factor VIII coagulant activity in patients with mild hemophilia A with exon 13 duplication.

Ectopic mRNA was analyzed by reverse transcriptase polymerase chain reaction (RT-PCR) in patients with duplication of F8 gene exon 13, a mutation which has been demonstrated to be a cause of mild hemophilia A in 32% of Northern Italian subjects. Two different transcripts originate from mutated genomic DNA, due to alternative splice processes. The larger-sized transcript contains both duplicated exons 13, the smaller one contains only one exon 13.

Familial nonrandom inactivation linked to the X inactivation centre in heterozygotes manifesting haemophilia A.

A basic tenet of the Lyon hypothesis is that X inactivation occurs randomly with respect to parental origin of the X chromosome. Yet, nonrandom patterns of X inactivation are common - often ascertained in women who manifest recessive X-linked disorders despite being heterozygous for the mutation. Usually, the cause of skewing is cell selection disfavouring one of the cell lineages created by random X inactivation.

Small FVIII gene rearrangements in 18 hemophilia A patients: five novel mutations.

Hemophilia A (HA) is a disorder caused by mutations of the FVIII gene, which is located on the tip of the long arm of the X chromosome. In a cohort of 18 unrelated Italian patients affected with HA of varying severity, we performed mutational screening of the gene by denaturing high-performance liquid chromatography (DHPLC) and direct sequencing of abnormal peaks. We identified five novel mutations and 9 previously reported DNA alterations.

Duplication of exon 13 causes one third of the cases of mild hemophilia A in northern Italy.

A rearrangement of exon 13 in the factor VIII gene has been identified as the causative mutation in 32% of Northern Italian patients with mild hemophilia A. We have demonstrated that all share a common haplotype, thus suggesting that the mutation likely occurred in a single ancestor. To date, no predominant mutation has been identified in mild hemophilia A, therefore it would be extremely useful to carry out more extensive studies to ascertain whether the mutation is confined to northern Italy.

Analysis of 18 novel mutations in the factor VIII gene.

We describe 18 novel mutations, unreported in the Haemophilia A mutation Databases, that have been identified in a cohort of unrelated, Italian patients affected with haemophilia A (HA). Screening of the factor VIII gene (FVIII) was performed using denaturing high-performance liquid chromatography (DHPLC) and direct sequencing. Eight mutations were characterized as non-missense alterations, and the remaining 10 were missense mutations.

Mutation analysis impact on the genetic counseling of sporadic hemophilia B families.

Previous studies have shown that hemophilia B (HB) is the result of several different mutations, mostly single nucleotide substitutions, in the factor IX (FIX) gene. In order to evaluate the impact of mutation analysis on genetic counseling in sporadic and uninformative HB familial pedigrees, we re-analyzed by the conformation sensitive gel electrophoresis (CSGE) technique 14 patients, previously studied by restriction fragment length polymorphisms (RFLPs). A single mutation was present within the FIX gene of each patient: 12 mutations were single base substitutions, 1 was a base insertion, and 1 was a four nucleotide deletion; 4/12 mutations have not been described so far.