ABSTRACT
Deficiency of amylo-1,6-glucosidase, 4-alpha-glucanotransferase enzyme (AGL or glycogen debrancher enzyme) is responsible for glycogen storage disease type III, a rare autosomal recessive disorder of glycogen metabolism. The AGL gene is located on chromosome 1p21, and contains 35 exons translated in a monomeric protein product. The disease has recognized clinical and biochemical heterogeneity, reflecting the genotype-phenotype heterogeneity among different subjects. The clinical manifestations of GSD III are represented by hepatomegaly, hypoglycemia, hyperlipidemia, short stature and, in a number of subjects, cardiomyopathy and myopathy. In this article, we discuss the genotypic-phenotypic heterogeneity of GSD III by the molecular characterization of mutations responsible for the disease on a collection of 18 independent alleles from the Mediterranean area. We identified by heteroduplex band shift, DNA direct sequencing, and restriction analysis, seven novel mutations (four nonsense point-mutations: R34X, S530X, R1218X, W1398X; two microinsertions: 1072insT and 4724insAA; and one bp deletion: 676DeltaG), together with two new cases carrying a IVS21 + 1 G --> A splicing site mutation previously described in Italian patients. Altogether, 15 alleles were characterized. The correlation between type of mutation and clinical severity was studied in six patients in whom both mutated alleles were detected. Our data confirm the extreme genetic heterogeneity of this disease, thus precluding a strategy of mutation finding based on screening of recurrent common mutations.
Subject(s)
Glycogen Debranching Enzyme System/genetics , Glycogen Storage Disease Type III/genetics , Adolescent , Adult , Aged , Base Sequence , Child , Child, Preschool , DNA/chemistry , DNA/genetics , DNA Mutational Analysis , Female , Genetic Variation , Glycogen Storage Disease Type III/enzymology , Glycogen Storage Disease Type III/pathology , Humans , Male , Mediterranean Region , Middle Aged , MutationABSTRACT
VCY2 is a gene positioned within the AZFc locus of the Y chromosome, a region frequently deleted in infertile males. To investigate the involvement of this gene in idiopathic male infertility, we studied its genomic organization and localization. Analysis of the genomic structure demonstrated that the VCY2 gene is composed of 9 exons spanning 21 kb. FISH analysis on interphase nuclei with specific probes for exons 4-6, 7, and 8 demonstrated the presence of a single gene copy, and Fiber-FISH on relaxed chromatin indicated that VCY2 is located within the DAZ gene cluster. PCR, Southern blot, and FISH analysis on infertile patients with Yq microdeletions demonstrated the absence of VCY2 in all cases where deletions involved the DAZ gene, raising the question about the role of the VCY2 gene loss in the phenotype reported for DAZ-deleted patients.
Subject(s)
Chromosome Deletion , Genes , Infertility, Male/genetics , Y Chromosome , Blotting, Southern , Chromosome Mapping , Humans , In Situ Hybridization, Fluorescence , Male , Molecular Sequence Data , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
The long arm of the Y chromosome contains genes mapped in loci involved in male infertility, short stature and gonadoblastoma. However, many of these genes have not been fully characterized, and are not currently investigated in patients affected by such diseases. We report a study aimed to the genomic characterization of 5 genes mapped within the Y chromosome: BPY2, PRY, TTY1, TTY2, and VCY. Exon-intron boundaries were detected for each gene, and PCR analysis was carried out to investigate the involvement of these genes in different re-arrangements of the Y chromosome. It was found that BPY2 and PRY are lost in some infertile patients with Yq microdeletions, suggesting that they could play a role in male gametogenesis. On the other hand, these patients retain some copies of TTYI and TTY2 genes, due to the presence of copies in Yp, and of VCY, which has homologous copies on the X chromosome. On the basis of their localization, these genes could be candidate for the gonadoblastoma locus (TTY1, TTY2) and for the control growth locus (VCY).
Subject(s)
Oligospermia/genetics , Base Sequence/genetics , Chromosome Mapping , Female , Genome , Humans , Male , Molecular Sequence Data , Polymerase Chain Reaction , Sequence Homology , Y Chromosome/geneticsABSTRACT
We investigated subinterval 6E on the human Y chromosome, a region frequently deleted in infertile males. YAC yOX17, mapped within subinterval 6E by STS-PCR, was analyzed for the presence of new genes. TSPYq1, a member of the TSPY multi-copy gene family, was isolated and characterized from a yOX17 cosmid subclone. PCR and FISH analysis performed on normal subjects and on patients with microdeletions of Yq suggested the presence of multiple copies of TSPY in Yq.
Subject(s)
DNA-Binding Proteins/genetics , Multigene Family/genetics , Nuclear Proteins , Transcription Factors , Y Chromosome/genetics , Amino Acid Substitution/genetics , Base Sequence , Cell Cycle Proteins , Chromosome Deletion , Chromosomes, Artificial, Yeast/genetics , Cloning, Molecular , Cosmids/genetics , Exons/genetics , Gene Dosage , Humans , In Situ Hybridization, Fluorescence , Infertility, Male/genetics , Male , Molecular Sequence Data , Physical Chromosome Mapping , Polymerase Chain Reaction , Sequence Alignment , Sex-Determining Region Y Protein , Spermatogenesis/geneticsABSTRACT
Inherited coagulation disorders have been diagnosed in many breeds of dogs as well as in mongrels and cats. This article presents the different coagulation factor deficiencies that are known to exist in small animals. A description is given of each coagulation factor along with the relevant clinical signs, inheritance, and the breeds affected. Suggestions are also given for the diagnosis and therapy of these deficiencies.
