Maryellen C. Sparkes

Evidence for a null allele at the esterase D (EC 3.1.1.1) locus.

SummaryElectrophoretic and quantitative assays of esterase D in a Caucasian family demonstrate the inheritance of a null allele, which was observed in the heterozygous state in six individuals.

Separation of retinoblastoma and esterase D loci in a patient with sporadic retinoblastoma and del(13)(q14.1q22.3)

SummaryA chromosome 13 deletion in a patient with sporadic retinoblastoma appears to have separated the loci for retinoblastoma and esterase D. This study indicates that: (1) the retinoblastoma locus is distinct from the esterase D locus; and (2) the linear order of these genes is centromere-esterase D-retinoblastoma.

Gene markers in human bone marrow transplantation.

Abstract. One or more differences between donors and recipients were found in polymorphic red blood cell antigens and enzymes in each of 56 bone marrow transplant sibling pairs. These results identify those polymorphic traits which are potentially most informative for detection of donor cells in a recipient following transplantation.

Regional mapping of ADA and ITP on human chromosome 20: cytogenetic and somatic cell studies in an X/20 translocation

An apparently balanced de novo translocation between chromosomes X and 20, 46,X,t(X;20)(Xp20q;Xq20p), was identified in a severely retarded 13-year-old female with macrocephaly, bilateral overfolded pinnae, elbow contractures, clinodactyly, and seizures. BudR-pulse studies show the normal X chromosome to be late replicating in both lymphocytes (50 cells) and skin fibroblasts (25 cells). An HPRT deficient Chinese hamster line was fused with lymphocytes from the patient, and hybrid lines were derived in HAT medium. Cytogenetic and biochemical analyses of these hybrid lines show that the locus for adenosine deaminase is in the cen leads to qter region and that the locus for inosine triphosphatase is in the pter leads to cen region of human chromosome 20.

Improved technique for electrophoresis of human galactose-1-p uridyl transferase (EC 2.7.7.12).

SummaryA newly developed electrophoretic technique for human galactose-1-phosphate uridyl transferase confirms the multiple band patterns for the Duarte and Los Angeles variants. This represents the first confirmation for the Los Angeles variant. The observed frequencies of N, D, and LA types are similar to earlier reports for these variants.

Genetic linkage studies of transferrin, pseudocholinesterase, and chromosome 1 loci

Genetic linkage analysis of a pedigree with four different alleles for pseudocholinesterase (CHE1) gives a positive lod score of 0.37 at theta = 0.16 for linkage with transferrin (TF), a finding which supports previous reports of linkage between CHE1 and TF. Evaluation of linkage relations of CHE1 and TF using unreported families from our data bank fails to establish linkage with chromosome 1 loci (6-PGD, Rh, PGM1, AMY2 and FY). These results are consistent with recent studies which suggest that TF is on human chromosome 3.

Late replication studies in a human X/13 translocation: correlation with autosomal gene expression

Chromosome replication pattern was reevaluated in an unbalanced X/13 translocation carrier, 46,X,der (X),t(X;13)(q27;q12), using the BudR-acridine orange technique. The translocated chromosome, Xpter leads to q27::13q12 leads to 13qter, was late replicating in all analyzed cells. The autosomal segment showed a replication pattern comparable to the two normal, and presumably genetically active, chromosome 13s, with the exception of band 13q22, which was consistently late replicating. Measurements of red-cell levels of esterase D (ESD) (a marker assigned to 13q14) showed a 50% increase in ESD activity, compared to that in normal controls and parents of the patient. This suggests noninactivation of the ESD locus on the der(X) chromosome, a finding consistent with the late-replication data.

Possible Assignment of a Dominant Retinitis pigmentosa Gene to Chromosome 1

A genetic linkage study, performed on a large family with autosomal dominant retinitis pigmentosa (RP), demonstrated that the RP gene may be linked to the Rh locus, known to be on the short arm of human chromosome 1. Linkage studies on RP along with other studies, can help to more accurately classify these disease entities. Localizing the RP gene locus has the potential for allowing the early diagnosis of individuals at risk.

Association studies between Type 1 (insulin-dependent) diabetes and 27 genetic markers: lack of association between Type 1 diabetes and Kidd blood group.

SummaryOne hundred and three unrelated patients with Type 1 (insulin-dependent) diabetes were typed for HLA, properdin factor B (BF), glyoxalase1 (GLO), Kidd blood group, and 24 other genetic markers. Observed distributions of marker phenotypes among these patients were compared with those expected according to population frequencies, in an attempt to detect associations between Type 1 diabetes and the markers. Strong associations between Type 1 diabetes and both HLA and properdin factor B were confirmed, as was a lack of association between Type 1 diabetes and glyoxalase (GLO). There was an apparent deviation from Hardy-Weinberg equilibrium at the GLO locus, and statistically significant distortions in the distributions of pancreatic amylase (AMY2), galactose-1-phosphate uridyl transferase (GALT), and groupspecific component (GC) among Type 1 diabetes patients, but these results are not significant when corrected for performance of multiple tests. An increase in the Lewis-negative phenotype reported elsewhere was observed here but was not statistically significant. A distortion in the distribution of Kidd types reported elsewhere was not confirmed.

Transferase-deficiency galactosemia: Immunochemical studies of the Duarte and Los Angeles variants

SummaryRabbit antibodies to purified human placental galactose-l-phosphate uridyltransferase (EC 2.7.7.12) were used to establish immunologic cross-reactivity patterns for the enzyme in hemolysates, prepared from red cells of a normal individual, a homozygous Duarte variant, and a heterozygous Los Angeles variant. The antibody immunoprecipitated all three forms of the enzyme. The amount of antibody absorbed by each hemolysate was related to the different levels of activity, and examination of hemolysate/antibody reaction mixtures by starch gel electrophoresis revealed that the antibody quantitatively precipitated all of the isoenzyme forms that characterize these three genetic variants.