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J M Puck

Publications and source records attributed to J M Puck.

At least 73 records · Page 4Linked to original sources

Comparative mapping of canine and human proximal Xq and genetic analysis of canine X-linked severe combined immunodeficiency.

Parallel genetic analysis of animal and human genetic diseases can facilitate the identification and characterization of the causative gene defects. For example, canine X-linked severe combined immunodeficiency (SCID) is characterized by clinical, pathological, and immunological manifestations similar to the most common form of human SCID. To derive a canine syntenic map including genes that in humans are located in proximal Xq, near human X-linked SCID, poly(TG) polymorphisms were identified at the canine phosphoglycerate kinase (PGK) and choroideremia (CHM) loci. These plus a polymorphic poly(CAG) sequence in exon 1 of the canine androgen receptor gene (AR) were used to genotype members of the colony informative for X-linked SCID. No recombinations among SCIDX1, AR, PGK, or CHM were observed. Fluorescence in situ hybridization localized PGK and CHM to proximal Xq in the dog, in the same chromosomal location occupied by the human genes. Somatic cell hybrid analysis and methylation differences at AR demonstrated that female dogs carrying X-linked SCID have the same lymphocyte-limited skewed X-chromosome inactivation patterns as human carriers. These genetic and phenotypic findings provide evidence that mutations in the same gene, now identified as the gamma chain of the IL-2 receptor, cause canine and human X-linked SCID. This approach is an efficient method for comparative gene mapping and disease identification.

Animals↗

IL-2R gamma gene microdeletion demonstrates that canine X-linked severe combined immunodeficiency is a homologue of the human disease.

X-linked severe combined immunodeficiency (SCID) is characterized by profound defects in cellular and humoral immunity and, in humans, is associated with mutations in the gene for the gamma chain of the IL-2 receptor (IL-2R gamma). We have examined this gene in a colony of dogs established from a single X-linked SCID carrier female. Affected dogs have a 4-bp deletion in the first exon of the IL-2R gamma gene, which precludes the production of a functional protein, demonstrating that the canine disease is a true homologue of human X-linked SCID.

Amino Acid Sequence↗

Molecular and genetic basis of X-linked immunodeficiency disorders.

Within a short time interval the specific gene defects causing three X-linked human immunodeficiencies, agammaglobulinemia (XLA), hyper-IgM syndrome (HIGM), and severe combined immunodeficiency (XSCID), have been identified. These represent the first human disease phenotypes associated with each of three gene families already recognized to be important in lymphocyte development and signaling: XLA is caused by mutations of a B cell-specific intracellular tyrosine kinase; HIGM, by mutations in the TNF-related CD40 ligand, through which T cells deliver helper signals by direct contact with B cell CD40; and XSCID, by mutations in the gamma chain of the lymphocyte receptor for IL-2. Each patient mutation analyzed to date has been unique, representing both a challenge for genetic diagnosis and management and an important resource for dissecting molecular domains and understanding the physiologic function of the gene products.

Agammaglobulinemia↗

Molecular basis for three X-linked immune disorders.

Gene defects causing three X-linked human immunodeficiencies, agammaglobulinemia (XLA), hyper-IgM syndrome (HIGM), and X-linked severe combined immunodeficiency (SCID), have been identified. These represent the first human disease phenotypes associated with three gene families already recognized to be important in lymphocyte development and signaling: XLA is caused by mutations of a B-cell specific intracellular tyrosine kinase; HIGM by mutations in the tumor necrosis factor-related CD40 ligand, through which T cells deliver helper signals by direct contact with B-cell CD40; and SCID by mutations in the gamma chain of the lymphocyte receptor for interleukin-2. The great variety of patient mutations in all three genes represent both a challenge for genetic diagnosis and a resource for dissecting molecular domains and physiologic functions of the gene products.

Chromosome Mapping↗

Localization of the 75-kDa inositol polyphosphate-5-phosphatase (INPP5B) to human chromosome band 1p34.

The 75-kDa (type II) inositol polyphosphate-5-phosphatase, originally described in platelets, is one of at least three known enzymes capable of dephosphorylating inositol-1,4,5-trisphosphate (IP3) to inositol-1,4-bisphosphate (IP2). To further characterize these enzymatic forms, we have mapped the gene (INPP5B) coding for the 75-kDa type II enzyme. Using a combination of human x rodent somatic cell hybrids and fluorescence in situ hybridization, we have determined that this gene maps to human chromosome band 1p34.

Animals↗

Twelve new polymorphic microsatellites on human chromosome 22.

A strategy directed at constructing polymorphic STSs from human chromosome 22 has yielded 15 poly(TG) microsatellite markers. A short insert plasmid library containing flow-sorted chromosome 22 DNA was screened with a labeled poly(AC) probe. A combination of sequencing techniques was used to identify the poly(TG) targets, primers were designed to flank these targets, and PCR screening was carried out on a panel of genomic and hybrid DNAs to determine heterozygosity and regional localization on chromosome 22. Twelve of the STSs are polymorphic. Markers with high heterozygosity have been localized to three subregions of 22q, with seven in the Giemsa-dark 22q12 band. The new chromosome 22 loci will be useful for mapping disease loci, for linkage analysis, and for PCR-based contig construction in the ongoing effort to map human chromosome 22.

Animals↗

Catheter-related Fusarium solani fungemia and pulmonary infection in a patient with leukemia in remission.

Members of the genus Fusarium are ubiquitous fungi uncommonly associated with infection. Disseminated fusariosis typically occurs in neutropenic hosts and carries a high mortality rate. We present a case of disseminated fusariosis that is unique in terms of its relative lack of symptomatology despite documentation of fungemia and pulmonary nodules. A summary of the literature is also presented.

Adolescent↗

The interleukin-2 receptor gamma chain maps to Xq13.1 and is mutated in X-linked severe combined immunodeficiency, SCIDX1.

The gene encoding the gamma chain of the lymphocyte interleukin-2 receptor has been cloned and shown to be required to associate with the beta chain in order for IL-2 internalization and cell activation to occur (1). We considered this gene, IL2RG, a candidate for the X-linked form of severe combined immunodeficiency at the SCIDX1 locus, in which affected males have impaired lymphocyte development. Using fluorescence in situ hybridization and PCR amplification of somatic cell hybrid DNAs, we mapped IL2RG to human Xq13.1, a location within the SCIDX1 critical region established by linkage analysis. The 4.2 kb IL2RG gene was sequenced, and its genomic organization was elucidated. Seven of 19 transformed B-lymphocyte cell lines with independent SCIDX1 mutations had absent or minimal IL2RG mRNA. Unique point mutations were documented to be specifically associated with the disease and the carrier state in four unrelated affected males and their family members: one in a boy with no detectable IL2RG mRNA, in which the mutation ablated a splice donor site; one causing premature chain termination; and two causing distinct amino acid changes. The demonstration of impaired IL2RG mRNA expression in males with X-linked SCID and of unique point mutations in SCIDX1 pedigrees constitutes powerful evidence that the SCIDX1 gene is IL2RG. Noguchi et al. (2) have independently published IL2RG mapping to Xq13 and discovery of mutations in three affected males. The specific pathogenesis of IL2RG mutations and approaches to gene therapy can now be addressed in the X-linked form of SCID.

Amino Acid Sequence↗

Prenatal diagnosis and genetic analysis of X-linked immunodeficiency disorders.

Several congenital immunodeficiency diseases can exhibit X-linked inheritance, including agammaglobulinemia, severe combined immunodeficiency, Wiskott-Aldrich syndrome, X-linked lymphoproliferative syndrome, and X-linked hyper-IgM syndrome. To date, the gene defects causing each of these X-linked immunodeficiencies have not been identified, and the pathogenic mechanisms whereby mutations in these genes result in immunodeficiency are obscure. Although rare, all are associated with severe infections from early life and high morbidity and mortality. Regional localization of each of these gene defects on the X chromosome has made possible carrier detection and prenatal diagnosis by linkage with polymorphic X chromosome markers in pedigrees demonstrating clear X-linked recessive inheritance. However, without a positive family history, it may not be possible to distinguish clinically between X-linked and autosomal forms. As a partial solution to this problem, it has now been established that female carriers of X-linked agammaglobulinemia, X-severe combined immunodeficiency, and Wiskott-Aldrich syndrome can be identified by the pattern of X chromosome inactivation in cell lineages targeted by each gene defect. As more families are offered the opportunity to use carrier detection and prenatal diagnosis, their decisions will reflect not only their personal experience with affected children with immunodeficiency, but also the clinical advances in bone marrow transplantation and immunomodulation.

Chromosome Mapping↗

Refinement of linkage of human severe combined immunodeficiency (SCIDX1) to polymorphic markers in Xq13.

The most common form of human severe combined immunodeficiency (SCID) is inherited as an X-linked recessive genetic defect, MIM 300400. The disease locus, SCIDX1, has previously been placed in Xq13.1-q21.1 by demonstration of linkage to polymorphic markers between DXS159 and DXS3 and by exclusion from interstitial deletions of Xq21.1-q21.3. We report an extension of previous linkage studies, with new markers and a total of 25 SCIDX1 families including female carriers identified by nonrandom X chromosome inactivation in their T lymphocytes. SCIDX1 was nonrecombinant with DXS441, with a lod score of 17.96. Linkage relationships of new markers in the SCIDX1 families were consistent with the linkage map generated in the families of the Centre d'Etude du Polymorphisme Humain (CEPH) and with available physical map data. The most likely locus order was DXS1-(DXS159,DXS153)-DXS106-DXS132-DXS4 53-(SCIDX1,PGK1, DXS325,DXS347,DXS441)-DXS447-DXS72-DXYS 1X-DXS3. The SCIDX1 region now spans approximately 10 Mb of DNA in Xq13; this narrowed genetic localization will assist efforts to identify gene candidates and will improve genetic management for families with SCID.

Dosage Compensation, Genetic↗

Maximum-likelihood analysis of human T-cell X chromosome inactivation patterns: normal women versus carriers of X-linked severe combined immunodeficiency.

Lymphocytes of female carriers of X-linked severe combined immunodeficiency (XSCID; McKusick 300400; HGM genetic locus designation SCIDX1) exhibit nonrandom X chromosome inactivation. This phenomenon reflects a tissue-specific selective disadvantage for lymphocyte progenitors with an XSCID mutation on the active X chromosome and presumably is analogous to the process that inhibits T-cell development in affected boys with a single XSCID-bearing X chromosome. We investigated the specificity of T-cell X chromosome inactivation pattern as an indicator of immunodeficiency carrier status, as follows: X-inactivation ratios determined in a control group of noncarrier women exhibited a wide range, 20%-86% of T-cells with the paternal X active. Maximum-likelihood analysis of these data suggested that, in humans, mature T-cells are derived from a small pool of only about 10 randomly inactivated stem cells. Despite the wide variability in normal X-inactivation ratios, X inactivation in XSCID carriers appeared far more markedly skewed. Therefore a maximum-likelihood odds-ratio test was developed and proved to be successful in predicting the carrier status of women in XSCID pedigrees. This test has made it possible to identify XSCID carriers among mothers of boys with the heterogeneous syndrome of sporadic severe combined immunodeficiency.

Adolescent↗

The gene encoding human TFE3, a transcription factor that binds the immunoglobulin heavy-chain enhancer, maps to Xp11.22.

TFE3, a member of the helix-loop-helix family of transcription factors, binds to the microE3 motif of the immunoglobulin heavy-chain enhancer and is expressed in many cell types. We have localized human TFE3 to the proximal short arm of the X chromosome using a somatic cell hybrid panel. A frequent RsaI RFLP detected by the TFE3 cDNA was found and used to confirm this location by linkage analysis in 20 pedigrees. Two-point and multipoint lod scores place TFE3 near markers in Xp11.22 with the most likely order DXS7-DXS255-TFE3-DXS146-DXS14.

Animals↗

Molecular analysis of X-linked agammaglobulinemia with growth hormone deficiency.

To address the relationship between the gene (or genes) that causes the syndrome of X-linked hypogammaglobulinemia with isolated growth hormone deficiency and the gene responsible for typical X-linked agammaglobulinemia (XLA), we have used cytogenetics, examination of X chromosome inactivation patterns in potential carriers of the defect, and linkage analysis to study two unrelated families in which the affected males had isolated growth hormone deficiency and immunologic findings indistinguishable from those of typical XLA. A deletion could not be demonstrated in either family by G-banded karyotypes or flow cytometric analysis of metaphase chromosomes. Studies of X inactivation showed that mothers of affected boys from both families exhibited selective use of a single X chromosome as the active X chromosome in B cells but not T cells. This pattern is the same as that seen in obligate carriers of typical XLA. Linkage analysis demonstrated the most likely location for this gene (or genes) to be the midportion of the long arm of the X chromosome between DXS3 and DXS94. This segment of the X chromosome, which constitutes approximately 5% of the total X chromosome, encompasses the gene for XLA. These findings are consistent with the combination of XLA and growth hormone deficiency being caused by a small, contiguous, gene deletion syndrome involving the gene for XLA or an allelic variant of the gene for typical XLA.

Agammaglobulinemia↗

Atypical presentation of Wiskott-Aldrich syndrome: diagnosis in two unrelated males based on studies of maternal T cell X chromosome inactivation.

Congenital thrombocytopenia may occur in isolation or accompanied by eczema and immunodeficiency, as part of the X-linked hereditary Wiskott-Aldrich syndrome (WAS). Because the clinical and immunologic picture of WAS is variable, particularly early in life, definite diagnosis cannot always be made in cases with a negative family history. Two unrelated males with sporadic congenital thrombocytopenia had only questionable immunologic abnormalities as infants, making them clinically indistinguishable from cases of isolated thrombocytopenia, although one developed episodic neutropenia and the other began to manifest a multisystem autoimmune disease at 2 years of age. Evaluation of X chromosome inactivation in the T cells of both patients' mothers showed each of these women to have the same highly skewed X chromosome inactivation pattern seen in carriers of typical familial WAS. A T-cell defect was subsequently directly demonstrated in the second patient, whose lymphocytes failed to proliferate to periodate and anti-CD43. Taken together, these data suggest the presence of T cell immunodeficiency consistent with WAS in these patients. Furthermore, their mothers were found to have a very high likelihood of being carriers, lending support to the diagnosis of a hereditary disease in these boys and making possible genetic prediction in other family members and subsequent pregnancies.

Dosage Compensation, Genetic↗