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E R McCabe

Publications and source records attributed to E R McCabe.

At least 37 records · Page 2Linked to original sources
PubMed1999

IMAGe, a new clinical association of intrauterine growth retardation, metaphyseal dysplasia, adrenal hypoplasia congenita, and genital anomalies.

We report three boys with adrenal hypoplasia congenita (AHC) and additional findings that represent a new syndrome, IMAGe: Intrauterine growth retardation, Metaphyseal dysplasia, AHC, and Genital anomalies. Each presented shortly after birth with growth retardation and severe adrenal insufficiency. Each of the three patients had mild dysmorphic features, bilateral cryptorchidism, a small penis, and hypogonadotropic hypogonadism. Skeletal surveys revealed metaphyseal dysplasia in all three and epiphyseal dysplasia in two. The patients had documented or suspected hypercalciuria and/or hypercalcemia, resulting in nephrocalcinosis in one and in prenatal liver and spleen calcifications in another. AHC presents most often either as an isolated abnormality, caused by mutations in the DAX1 gene, or as part of an Xp21 contiguous gene syndrome, caused by a deletion of the Duchenne muscular dystrophy, glycerol kinase, and DAX1 genes. All three patients with the IMAGe association had normal creatine kinase levels and no evidence of glycerol kinase deficiency. Sequence analysis of DNA from these patients revealed no mutation in the DAX1- or steroidogenic factor-1-coding sequences, nor was a deletion of DAX1 detected. Identification of the molecular basis of the IMAGe association will give new insight into the pathogenesis of this syndromic relationship involving bone, adrenal cortical, and pituitary development.

Adrenal Insufficiency↗
PubMed1998

Mammalian sex determination: from gonads to brain.

In mammals, sex is determined by the Y chromosome, which encodes a testis-determining factor (TDF). This factor causes the undifferentiated embryonic gonads to develop as testes rather than ovaries. The testes subsequently produce the male sex hormones that are responsible for all male sexual characteristics. In 1990, the sex-determining gene, TDF, was identified and termed SRY in humans (Sry in mice). It encodes a protein containing a high mobility group (HMG) motif, which confers the ability to bind and to bend DNA. Genetic evidence supporting SRY as TDF came from the observation of a male phenotype in XX mice transgenic for a small genomic fragment containing Sry, and from the study of XY sex-reversed individuals who harbor de novo mutations in the SRY coding sequence. Other non-Y-linked genes involved in sex determination were subsequently found by genetic analysis of XY sex-reversed patients not explained by mutations in SRY. These genes are WT1, SF1, DAX1, and SOX9. A regulatory cascade hypothesis for mammalian sex determination, proposing that SRY represses a negative regulator of male development, was recently supported by observation of mice that expressed a DAX1 transgene and developed as XY sex-reversed females. The role of some sex-determining genes, such as DAX1 and SF1, in the development of the entire reproductive axis, a functionally integrated endocrine axis, leads to a new concept. Normal sexual development may result from the functional and developmental integration of a number of different genes that play roles in sex determination, sexual differentiation, and sexual behavior.

Amino Acid Sequence↗
PubMed1998

Developmental expression of hexokinase 1 and 3 in rats.

Mammalian hexokinase types one and three (HK1 and HK3) are 100 kDa isozymes that phosphorylate glucose to glucose-6-phosphate. HK1 is present in most tissues but is especially prominent in brain and kidney. HK3 is less well studied, but may be most prominent in the spleen and lymphocytes. In this study, we determined the ontogeny of the expression of these isoforms in the rat. Using immunohistochemistry, we identified HK1 and HK3 immunoreactivity in the brain, heart, kidney, liver, skeletal muscle and spleen from gestational day 14 (E14) to 45 days after birth (P45). With the exception of the liver and spleen, we observed a similar age- and cell-dependent staining pattern for both isoforms in all organs studied. The brain and spleen were analyzed in more detail to identify specific regions of immunoreactivity during maturation. A transient expression of HK1 and HK3 was noted in the cell bodies of mature neurons, including layers V and VI of the cerebral cortex and the cerebellar Purkinje cells followed by localization to the white matter of the cerebrum and cerebellum. In the spleen, HK3 immunoreactivity was detected postnatally and appeared to track with the infiltration of B cells. Our demonstration of changing patterns of immunoreactivity for HK1 and HK3 in fetal and postnatal organs suggests that these HK isoforms are involved the process of development. We speculate that HK1 and HK3 share a complex interaction during development of these organs and regulate glucose metabolism at multiple levels during development.

Animals↗
PubMed1998

Minipuberty of infancy and adolescent pubertal function in adrenal hypoplasia congenita.

An infant and his uncle, both with adrenal hypoplasia congenita, shared the same DAX1 mutation. The adolescent uncle had hypogonadotropic hypogonadism, but the infant had a normal minipuberty of infancy. These observations suggest differences in the physiologic mechanisms regulating the hypothalamic-pituitary-gonadal axis in infancy and adolescence.

Adolescent↗
PubMed1998

DAX1 mutations map to putative structural domains in a deduced three-dimensional model.

The DAX1 protein is an orphan nuclear hormone receptor based on sequence similarity in the putative ligand-binding domain (LBD). DAX1 mutations result in X-linked adrenal hypoplasia congenita (AHC). Our objective was to identify DAX1 mutations in a series of families, to determine the types of mutations resulting in AHC and to locate single-amino-acid changes in a DAX1 structural model. The 14 new mutations identified among our 17 families with AHC brought the total number of families with AHC to 48 and the number of reported mutations to 42; 1 family showed gonadal mosaicism. These mutations included 23 frameshift, 12 nonsense, and six missense mutations and one single-codon deletion. We mapped the seven single-amino-acid changes to a homology model constructed by use of the three-dimensional crystal structures of the thyroid-hormone receptor and retinoid X receptor alpha. All single-amino-acid changes mapped to the C-terminal half of the DAX1 protein, in the conserved hydrophobic core of the putative LBD, and none affected residues expected to interact directly with a ligand. We conclude that most genetic alterations in DAX1 are frameshift or nonsense mutations and speculate that the codon deletion and missense mutations give insight into the structure and function of DAX1.

Adrenal Glands↗
PubMed1997

Identification of a ferritin light chain pseudogene near the glycerol kinase locus in Xp21 by cDNA amplification for identification of genomic expressed sequences.

We used cDNA amplification for identification of genomic expressed sequences (CAIGES) to identify genes in the glycerol kinase region of the human X chromosome. During these investigations we identified the sequence for a ferritin light chain (FTL) pseudogene in this portion of Xp21. A human liver cDNA library was amplified by vector primers, labeled, and hybridized to Southern blots of EcoRI-digested human genomic DNA from cosmids isolated from yeast artificial chromosomes in the glycerol kinase region of Xp21. A 3.1-kb restriction fragment hybridized with the cDNA library, was subcloned and sequenced, and a 440-bp intronless sequence was found with strong similarity to the FTL coding sequence. Therefore, the FTL pseudogene that had been mapped previously to Xp22.3-21.2 was localized specifically to the glycerol kinase region. The CAIGES method permits rapid screening of genomic material and will identify genomic sequences with similarities to genes expressed in the cDNA library used to probe the cloned genomic DNA, including pseudogenes.

Base Sequence↗
PubMed1997

DAX1 gene expression upregulated by steroidogenic factor 1 in an adrenocortical carcinoma cell line.

Two nuclear hormone receptor superfamily members, DAX1 and SF1, are required for normal adrenal cortical development. Mutations in DAX1 are responsible for X-linked adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism. Steroidogenic Factor 1 (SF1) regulates the expression of a number of steroidogenic genes and a putative SF1 response element (SF1-RE) in the DAX1 promoter which binds SF1 specifically. Therefore, we examined deletions in the DAX1 promoter driving expression of beta-galactosidase, with and without coexpression of SF1, in the human adrenocortical carcinoma cell line NCI-H295. We defined the DAX initiation start site and localized the putative SF1-RE at -135 to -143 bp. Loss of the putative SF1-RE region or specific removal of the 9-bp SF1 site resulted in decreased transcriptional activity by 2.3-to 2.5-fold. When cotransfected with 1550 bp of the DAX1 promoter, an SF1-containing expression vector increased the transcriptional activity of the DAX1 promoter by 4-fold. No significant change above baseline occurred when the cells were cotransfected with the 1541-bp fragment containing the entire 1550-bp promoter region minus the 9-bp SF1-RE. We conclude that the SF1-RE is an enhancer element within the DAX1 promoter and speculate that SF1 may be a transcription factor that acts, at least in part, through DAX1 for normal adrenal cortical development.

Adrenocortical Carcinoma↗
PubMed1996

Ahch, the mouse homologue of DAX1: cloning, characterization and synteny with GyK, the glycerol kinase locus.

We cloned the murine full-length cDNA encoding Ahch, the mouse homologue of DAX1 (DSS-AHC Region on Human X Chromosome, Gene1) which is the gene responsible for human X-linked adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism (HH). Sequence analysis revealed that the murine and human cDNAs have 65% aa identity and 75% aa similarity overall. The cysteine residues in the putative DNA binding domain, which may interact with Zn2+ ions to form zinc fingers, are 100% conserved between the two species, indicating that the novel zinc-finger structures in DAX1 may be functional. In addition, mouse interspecific backcrosses show that the Ahch gene is closely linked to the glycerol kinase locus, GyK, on the mouse X chromosome, indicating that the order of the loci is conserved in this syntenic region between mouse and human.

Adrenal Glands↗
PubMed1996

Medical genetics.

Explore the source record for details and available documents.

Ataxia Telangiectasia↗
PubMed1996

Guidelines for the retention, storage, and use of residual dried blood spot samples after newborn screening analysis: statement of the Council of Regional Networks for Genetic Services.

These guidelines provide scientific information for policy development by state health departments considering appropriate use of newborn screening specimens after screening tests are finished. Information was collected, debated, and formulated into a policy statement by the Newborn Screening Committee of the Council of Regional Networks for Genetic Services (CORN), a federally funded national consortium of representatives from 10 regional genetics networks. Newborn screening programs vary widely in approaches and policies concerning residual dried blood spot samples (DBS) collected for newborn screening. Recognition of the epidemiological utility of DBS samples for HIV seroprevalence surveys and a growing interest in DBSs for DNA analysis has intensified consideration of issues regarding retention, storage, and use of residual DBS samples. Potentially these samples provide a genetic material "bank" for all newborns nationwide. Their values as a resource for other uses has already been recognized by scientists, administrators, and judicial officials. Programs should promulgate rules for retention and use of residual newborn screening DBS samples based on scientifically valid information. Banking of newborn samples as sources of genetic material should be considered in light of potential benefit or harm to society.

Blood Specimen Collection↗
PubMed1996

Genomic sequence of the DAX1 gene: an orphan nuclear receptor responsible for X-linked adrenal hypoplasia congenita and hypogonadotropic hypogonadism.

The gene responsible for X-linked adrenal hypoplasia congenita, DAX1, encodes a member of the nuclear hormone receptor superfamily. We sequenced 8851 bp that contained the DAX1 genomic region. The DAX gene was composed of two exons and one 3.4-kilobase intron. Putative TATA and GC boxes and a putative steroidogenic factor 1 response element were present in the 5'-flanking region. Two potentially polymorphic short tandem repeats were identified. The first exon encoded two putative novel zinc finger motifs within a putative DNA binding domain and part of the ligand binding domain, and the second exon encoded the remainder of the ligand binding domain. Although the putative DNA binding domain of DAX1 does not contain substantial sequence similarity to other nuclear hormone receptor superfamily members, the putative ligand binding domain had remarkable similarity to other family members. Single-strand conformational polymorphism analysis permitted identification of three new mutations in DAX1. In conclusion, single-strand conformational polymorphism analysis facilitates identification of mutations in the DAX1 gene, and the short tandem repeats may permit linkage analysis in families in which mutations are not yet identified. We speculate that DAX1 may be the most primitive member of the nuclear hormone receptor superfamily identified in mammals.

Adrenal Insufficiency↗
PubMed1996

The gene responsible for adrenal hypoplasia congenita, DAX-1, encodes a nuclear hormone receptor that defines a new class within the superfamily.

X-linked adrenal hypoplasia congenita (AHC) is an inherited disorder of the development of the adrenal cortex. The gene responsible for this genetic disorder has been identified using positional cloning methods and has been named DAX-1 based on its localization within the dosage-sensitive sex reversal (DSS) locus and the AHC locus on the X chromosome. The DAX-1 gene consists of two exons separated by a 3.4 kb intron. Analysis of DNA from patients with deletions in the AHC critical region in the X chromosome provided strong indication for the involvement of the DAX-1 gene in X-linked AHC. A number of intragenic mutations within the DAX-1 gene have also been identified in patients with isolated AHC. The DAX-1 gene product belongs to the nuclear hormone receptor superfamily based on the presence of an entire ligand binding domain present in the carboxy-terminal region of the receptor. However, DAX-1 has a domain structure which is very unusual with respect to other nuclear hormone receptor superfamily members. The amino-terminal portion of DAX-1 contains a novel domain consisting of 3.5 repeats of a 65-67 amino acid motif that contains two putative zinc finger structures in place of the more usual amino-terminal domain, DNA binding domain, and hinge region of the typical nuclear hormone receptors. It has been proposed that the amino-terminal portion of the DAX-1 protein is the DNA binding domain. The expression pattern of DAX-1 suggests that it may play a role in the regulation of steroidogenesis. Not only is DAX-1 expressed in the adrenal glands, but it is also expressed in the ovaries and testes. Most recently, we demonstrated that DAX-1 is also expressed in the hypothalamus and pituitary gland. The expression of DAX-1 in the neuroendocrine system suggests that interruption of the expression in these tissues may be the cause of the hypogonadotropic hypogonadism (HH) that is frequently associated with AHC. Interestingly, hybridization of a human DAX-1 cDNA probe with genomic DNA from various species indicated that a DAX-1 homologue may exist in yeast. Thus, DAX-1 or a DAX-1-like transcription factor may be the most primitive member of the nuclear hormone receptor superfamily. Although the molecular mechanism of action of DAX-1 is not yet characterized, its importance for the development and physiology of the adrenal gland and gonads is indicated by its involvement in AHC and HH. Analysis of the functions of DAX-1 along with its regulation of expression will not only provide information concerning the actions of this new member of the nuclear hormone receptor superfamily, but will also yield insight into the pathogenesis of AHC and HH and may allow for the development of gene therapy protocols for the treatment of these diseases.

Adrenal Insufficiency↗
PubMed1995

Identification of a putative steroidogenic factor-1 response element in the DAX-1 promoter.

The nuclear hormone receptor, DAX-1, is responsible for X-linked adrenal hypoplasia congenita and hypogonadotrophic hypogonadism. We recently cloned the 5' flanking region of the human DAX-1 gene and in this report we describe the identification of a putative steroidogenic factor 1 (SF-1) response element approximately 110 bases upstream of the TATA box. Both DAX-1 and SF-1 are expressed in similar tissues including the adrenal cortex, gonads, hypothalamus, and the pituitary gland. Like DAX-1, SF-1 expression has been shown to be essential for the development of the adrenal cortex. We demonstrate that SF-1 is able to efficiently bind to the putative SF-1 response element found in the DAX-1 promoter in vitro. This suggests that SF-1 may directly regulate the expression of DAX-1 and that these two transcription factors may be components of a cascade required for development of steroidogenic tissues.

Base Sequence↗