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Biomedical subjects

D A Applegarth

Publications and source records attributed to D A Applegarth.

At least 37 records · Page 2Linked to original sources
PubMed1996

Nonketotic hyperglycinemia: atypical clinical and biochemical manifestations.

A 16-year-old boy had intermittent chorea, delirium, and vertical gaze palsy precipitated by febrile illness. Nonketotic hyperglycinemia was confirmed by measurement of liver and lymphoblast glycine cleavage enzyme activity. Deficient but residual enzyme activity was demonstrated in both tissues, possibly accounting for the mild phenotype. Confirmation of an atypical variant of nonketotic hyperglycinemia with residual glycine cleavage enzyme activity has important implications for diagnosis and treatment.

Adolescent↗
PubMed1994

Murine alpha-L-iduronidase: cDNA isolation and expression.

As an initial step toward the generation of a murine model for mucopolysaccharidosis type I, we have identified and characterized a full-length murine alpha-L-iduronidase cDNA. Expression of the murine cDNA in COS-1 cells results in the production of alpha-L-iduronidase enzyme activity at a level 20-fold higher than that of the endogenous gene. The murine cDNA shows strong homology with the coding region of both the human and the canine homologs with 78 and 75% nucleotide sequence identity, respectively. In contrast to the coding region, significant diversity of sequence exists for the 5' and 3' untranslated regions between the murine and both the human and the canine sequence. The 3' UTR of the murine transcript is 1193 bp in length, as compared to the human (100 bp) and canine (139 bp), and contains a CA dinucleotide repeat not seen in either the human or the canine genes. A portion of the murine iduronidase coding sequence overlaps with sequence reported for the 3' UTR of the murine SAT-1 cDNA. The sequence overlap involves the proposed exon II of murine iduronidase and covers 141 bp of sequence with the transcripts generated in opposite orientation. We report here the characterization of murine alpha-L-iduronidase cDNA and its relationship to SAT-1.

Animals↗
PubMed1994

DNA analysis of an uncommon missense mutation in a Gaucher disease patient of Jewish-Polish-Russian descent.

Gaucher disease is the most frequent lysosomal lipid storage disease. It results from deficient glucocerebrosidase activity and is transmitted as an autosomal recessive trait. Three clinical forms of Gaucher disease have been described: type 1, non-neuronopathic; type 2, acute neuronopathic; and type 3, subacute neuronopathic. We have sequenced the full length cDNA of the glucocerebrosidase gene and identified an uncommon mutation in nucleotide position 1604 (genomic DNA nucleotide position 6683) from a Gaucher disease patient of Jewish-Polish-Russian descent with type 1 Gaucher disease. It is a G-->A transition in exon 11 that results in 496Arg-->496His of glucocerebrosidase. This missense mutation is present in the heterozygous form and creates a new cleavage site for the endonuclease HphI. We have developed a simple method to detect the presence of this mutation by using HphI restriction fragment length polymorphism analysis of glucocerebrosidase genomic DNA or cDNA. The mutation in the other Gaucher allele of this patient is an A-->G transition at cDNA nucleotide position 1226 which creates an XhoI cleavage site after PCR mismatch amplification. The presence of this mutation was also confirmed by sequence analysis. Based on previous reports that mutation 1226 is present only in type 1 Gaucher disease and the observation that there is no neurological involvement in this patient, we conclude that our patient with the 1226/1604 genotype is diagnosed as having type 1 Gaucher disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

The differential diagnosis of adult onset metachromatic leukodystrophy and early onset familial Alzheimer disease in an Alzheimer clinic population.

Clinical differentiation between forms of progressive dementia can prove difficult, particularly when relatively rare forms of dementia are involved. Factors such as family history of dementia, age at onset, presenting features such as personality change, cognitive deficits, psychiatric symptoms, and clinical course (progressive deterioration; retention of skills over time) may prove useful for directing investigations to identify underlying pathology and genetic implications. This is illustrated by two patient reports. Each patient had the onset of memory/behavioral problems at approximately age 40 years, was initially given a psychiatric, non-dementing diagnosis, and had a positive family history for early onset behavioral and memory problems. After longitudinal assessment, the diagnosis of Alzheimer disease was confirmed at autopsy in one patient and a diagnosis of familial, adult-onset metachromatic leukodystrophy in the other.

Alzheimer Disease↗
PubMed1992

Prenatal diagnosis of non-ketotic hyperglycinaemia.

Non-ketotic hyperglycinaemia (NKH) is a devastating neurological disease for which there is no effective therapy. Consequently, most couples with a pregnancy known to be at risk for NKH request prenatal diagnosis. We have applied the combination of chorionic villus (CVS) assay for glycine cleavage enzyme activity and determination of amniotic fluid glycine concentration to increase the reliability of prenatal diagnosis for this disorder beyond that of each of these methods alone. All 15 of the at-risk pregnancies monitored had CVS glycine cleavage assay and five also had amniotic fluid glycine measurements. Two cases had no detectable cleavage activity in CVS and one gave uninterpretable enzyme results. Amniotic fluid glycine concentration was increased in all three and NKH was confirmed by abortus tissue assays for cleavage activity and amino acids. The remaining 12 case had activity in CVS (two also had normal amniotic fluid glycine levels) and delivered unaffected infants. Four of these 12 cases had cleavage activities below or at the low end of the normal range, perhaps indicating carrier status. We believe that the combination of CVS glycine cleavage assay and amniotic fluid glycine measurement is currently the best approach to the prenatal diagnosis of NKH.

Amino Acid Metabolism, Inborn Errors↗
PubMed1991

Prenatal diagnosis of molybdenum cofactor deficiency by assay of sulphite oxidase activity in chorionic villus samples.

Molybdenum cofactor deficiency is characterized by the absence of sulphite oxidase, xanthine dehydrogenase and aldehyde oxidase, the three known enzymes in man that require the cofactor for their activity. Prenatal diagnosis of the deficiency may be performed by assay of sulphite oxidase activity in cultured amniocytes. However, the activity in amniocytes is low and large numbers of cells are required for reliable assessment. We show that sulphite oxidase is present at high levels in chorionic villi obtained at 10-14 weeks gestation and can be assayed directly in the biopsy sample without cell culture. This assay has been applied to two pregnancies at risk for molybdenum cofactor deficiency with successful diagnoses of an unaffected and an affected fetus.

Aldehyde Oxidase↗
PubMed1990

Biochemical investigation of a child with molybdenum cofactor deficiency.

A girl aged eight months, who presented with developmental delay and dislocated optic lenses, was diagnosed as having combined sulfite oxidase and xanthine dehydrogenase deficiencies consistent with molybdenum cofactor deficiency. The diagnosis was confirmed by demonstrating the absence in urine of urothione, a molybdenum cofactor metabolite. Prenatal diagnosis excluded the disease in the mother's second pregnancy. A summary of an in vitro study of molybdenum cofactor synthesis in the patient is given.

Coenzymes↗
PubMed1990

Congenital rubella syndrome associated with calcific epiphyseal stippling and peroxisomal dysfunction.

An infant girl had the clinical and immunologic findings of congenital rubella syndrome but also had arthrogryposis multiplex and calcific epiphyseal stippling. Spastic quadriparesis developed, and both physical and behavioral development were slow. Increased spasticity of the legs at 5 1/2 years was related not to progressive rubella encephalomyelopathy but to spinal cord compression by abnormal cartilaginous tissue. The presence of a peroxisomal disorder was demonstrated by a greatly increased level of phytanic acid and slightly increased levels of hexacosanoate in serum and by reduced activity of peroxisomal dihydroxyacetone phosphate acyltransferase and a slightly increased ratio of cytosolic to peroxisomal catalase activity in cultured fibroblasts. A reduction in the number and size of peroxisomes was demonstrated in cultured fibroblasts, and a needle biopsy specimen of the liver also showed the peroxisomes to have a smaller diameter than usual. We recommend that any child with epiphyseal stippling be assessed for peroxisomal disease and that the potential for spinal cord compression by dysplastic bone or cartilage be recognized. The association of peroxisomal dysfunction with congenital rubella has not been described previously. The interaction between rubella virus infection and peroxisomal function may need further investigation.

Calcinosis↗