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R G Weleber

Publications and source records attributed to R G Weleber.

At least 109 records · Page 6Linked to original sources
PubMed1983

Ruvalcaba-Myhre-Smith syndrome: a case with probable autosomal-dominant inheritance and additional manifestations.

We report on a 7 1/2-year-old boy with macrocephaly, hamartomatous intestinal polyps, and café-au-lait spots on the penis. These abnormalities were reported in two other individuals thought to have the Sotos syndrome. We think that this triad of abnormalities represents a new disorder, the Ruvalcaba-Myhre-Smith syndrome. Prominent Schwalbe lines, prominent corneal nerves, and lipid storage myopathy also appear to be part of the syndrome. Macrocephaly, similar facial appearance, and a hamartomatous polyp in the mother suggest dominant inheritance.

Child↗
PubMed1983

Iris hamartomas (Lisch nodules) in a case of segmental neurofibromatosis.

Iris hamartomas (Lisch nodules), previously reported in cases of peripheral neurofibromatosis, were found in a 14-year-old girl with segmental neurofibromatosis. The girl was in the 75th percentile for height (168 cm), the 90th percentile for weight (63 kg), and the 50th percentile for head circumference (55 cm). Her blood pressure was 105/70 mm Hg. Her visual acuity (20/20 and J 1), ocular motility, pupillary responses, visual fields, color vision, stereopsis, and intraocular pressure were within normal limits. Biomicroscopy showed several tan elevated nodular hamartomas on the anterior surface of the right peripheral iris but none elsewhere in the right eye and none in the left eye. Café-au-lait spots and freckling were also limited to the right side of the body. The child had no palpable neurofibromas and was in good health and of normal intelligence. There was no family history of neurofibromatosis, multiple café-au-lait spots, axillary freckling, macrocephaly, or learning disabilities. The absence of iris hamartomas has been used to distinguish segmental neurofibromatosis from the peripheral and central or acoustic forms. Thus, their presence in this case is clinically significant. The segmental form not only produces fewer complications but carries less genetic risk. In segmental neurofibromatosis, the Lisch nodules would be expected to be unilateral rather than bilateral, ipsilateral to the side of the cutaneous involvement, and more frequently associated with contiguous cutaneous lesions.

Adolescent↗
PubMed1981

Digoxin retinal toxicity. Clinical and electrophysiological evaluation of a cone dysfunction syndrome.

A 70-year-old man was studied both during and after resolution of clinical digoxin toxicity using color vision tests, ganzfeld electroretinography and electro-oculography. Concomitant administration of quinidine sulfate probably contributed to digoxin toxicity. Abnormalities in color vision and subnormal amplitude and prolonged implicit time for cone-mediated electroretinogram (ERG) responses suggested a cone dysfunction syndrome. The electro-oculographic light-to-dark ratio during clinical toxicity was high for our laboratory, but this is probably normal. Notable improvement was seen in color vision and the ERG after cessation of digoxin therapy. Inhibition of sodium-potassium adenosine triphosphatase by digoxin probably influences normal uptake of extracellular potassium by Müller's cells and other retinal neurons. This mechanism may contribute to subnormal, prolonged cone-mediated ERG responses in retinal toxic reactions from cardiac glycosides.

Adaptation, Ocular↗
PubMed1981

Gyrate atrophy of the choroid and retina. Approaches to therapy.

Gyrate atrophy of the choroid and retina is caused by deficient activity of ornithine ketoacid aminotransferase, a pyridoxal phosphate dependent enzyme. Besides the typical eye findings, abnormalities have been found on muscle biopsy, electro-encephalography, electromyography and electrocardiography, establishing this as a generalized disorder. Ornithine is markedly elevated in plasma and other body fluids. Plasma lysine, glutamate, glutamine and creatine are reduced. The possible contributions of these biochemical disturbances to the pathogenesis of gyrate atrophy are discussed. The disease is one of the few examples of an inherited chorioretinal dystrophy whose underlying biochemical defect is known. It therefore offers a unique opportunity to develop and test rational approaches to therapy. These include lowering of the abnormally high ornithine by dietary restriction of its precursor arginine, facilitation of ornithine excretion by administration of alpha-aminoisobutyric acid, replacement of deficient products such as lysine or creatine, or increasing residual enzyme activity by high levels of cofactor (vitamin B6). The results of several studies employing such approaches to therapy are presented as well as preliminary indications of possible benefit in a few patients.

Adult↗
PubMed1981

Clinical trial of vitamin B6 for gyrate atrophy of the choroid and retina.

Seven patients with gyrate atrophy and deficiency of ornithine-delta-aminotransferase were studied for in vivo pyridoxine responsiveness; three responded to oral vitamin B6 with over 50% reduction of serum ornithine levels and return to normal of serum lysine levels. Electrophysiologic studies were performed on two B6-responsive patients and one B6-nonresponder over various time periods with and without pyridoxine supplementation. Electroretinogram (ERG) amplitudes improved 100% in one patient when initially given high doses of vitamin B6. Electro-oculogram light-to-dark ratio also improved for this patient. Withdrawal followed by resumption of B6 supplementation was associated with mild worsening followed by improvement of ERG responses respectively in both patients. Long-term follow-up will be needed to assess whether pyridoxine treatment will slow or halt the progression of the disease.

Analysis of Variance↗
PubMed1981

The effect of age on human cone and rod ganzfeld electroretinograms.

The ganzfeld-evoked electroretinogram (ERG) is the most effective measure of the mass electrical response of cones and rods; however, all variables affecting the various components of the ERG have not been identified. The scotopic b-wave amplitude has been appreciated to be age-dependent, but little or no information exists in the literature regarding age dependency for other components. Linear regression analysis against age and multiple regression analysis against age and log intensity of the stimulus were performed on ERG responses from 24 prospectively normal subjects. Significant age dependency was found for scotopic rod-mediated b-wave amplitude, scotopic mixed rod-and cone-mediated bx-wave amplitude, and for photopic cone-mediated and b-wave amplitude. No significant age correlation was found for dark-adapted cone a-wave amplitude, scotopic cone-mediated x-wave amplitude, scotopic a-wave amplitude from mixed rod and cone responses to bright stimuli, or for implicit times for any scotopic or photopic responses. These findings indicate that for clinical patient evaluation, age-corrected normal ranges derived from linear or multiple regression coefficients should be used for rod- and cone-mediated b-wave response, whereas normal ranges derived from mean and standard deviation are more appropriate for scotopic a-wave amplitude, scotopic cone-mediated x-wave amplitude, and for all implicit times.

Adolescent↗
PubMed1980

Gyrate atrophy of the choroid and retina with hyperornithinemia: biochemical and histologic studies and response to vitamin B6.

Four patients with hyperomithinemia and gyrate atrophy of the choroid and retina age described. In vivo response to vitamin B6 is documented in three of the four patients by significant reduction of fasting serum ornithine and increase of lysine after oral B6 supplementation. Oral glucose tolerance testing in one patient resulted in marked changes in serum ornithine and lysine concentrations, in addition to mild glucose intolerance. Histochemical staining of punch muscle biopsies showed intracellular inclusions in type 2 muscle fibers. Tubular aggregates, approximately 60 nm in diameter and adjacent to the sarcoplasmic membrane, were seen on electron microscopy. Obligate heterozygotes had a mean serum ornithine slightly higher than normal, but there was considerable overlap with the normal range. Oral ornithine tolerance tests distinguished carriers from controls in only one of five cases. Deficient activity of ornithine ketoacid aminotransferase (OKT) in cultured skin fibroblasts was documented in all four patients. Approximately half-normal levels were found in obligate heterozygotes. In vitro response to B6 was manifest by increased OKT activity at increased concentrations of pyridoxal phosphate in fibroblasts from the patients.

Adult↗
PubMed1978

Aicardi's syndrome. Case report, clinical features, and electrophysiologic studies.

Aicardi's syndrome consists of abnormalities of the ocular fundus, myoclonic seizures, mental retardation, and congenital malformations of the brain and vertebral column in females. The pathognomonic chorioretinal lesions were noted on ophthalmologic examination of a 22-month-old girl, observed for 19 months with severe myoclonic seizures and profound mental retardation. Computerized tomography confirmed major malformation of the brain. Roentgenograms showed anterior fusion of two thoracic vertebrae. Electroretinography was normal, but visual evoked responses were abnormal. Only 72 children are known to have this syndrome; no affected siblings have been reported. The absolute sex limitation--all cases have been female--suggests that the disorder is produced by a mutation on one of the X chromosomes, and is nonviable in male conceptuses. These genetic considerations dramatically influence counseling of parents regarding likelihood of occurrence of the syndrome in subsequent offspring.

Abnormalities, Multiple↗
PubMed1977

Cytogenetic investigation of cat-eye syndrome.

Using multiple chromosomal banding techniques, we studied a child with typical cat-eye syndrome and ocular retraction syndrome. Although the mother was was chromosomally normal, other maternal relatives showed features of the cat-eye syndrome, suggesting the basic abnormality is heritable. The abnormal chromosome in our case was most likely the product of reciprocal translocation where short arm plus centromeric chromatin from two separate acrocentric chromosomes fused together. The chromosomes involved were probably No. 22 and either Nos. 13 or 14. The basic underlying defect in cat-eye syndrome may be a heritable fragile site or some other predisposition leading to complex chromosomal interchange.

Adult↗
PubMed1976

The Hajdu-Cheney syndrome. Report of two cases and review of the literature.

The Hajdu-Cheney syndrome includes short stature, characteristic facies, and a slowly progressive skeletal dysplasia which affects skull, spine, and long bones. Two patients with this syndrome are presented. In the first patient the most distinctive skeletal feature, acro-osteolysis, was shown to be absent at age 6 years but was present at age 11 years. Diagnosis was made in the second case in the absence of acroosteolysis because of otherwise typical findings. Abnormalities affecting vision, hearing, and dentition occur and these, along with the other characteristic physical and radiographic features of the syndrome, should enable diagnosis prior to the onset of acro-osteolysis.

Abnormalities, Multiple↗
PubMed1976

Duplication-deficiency of the short arm of chromosome 8 following artificial insemination.

A chromosomally abnormal child with psychomotor retardation and multiple anomalies, including agenesis of the corpus callosum and cleft palate, was born following artificial insemination by donor. Chromosomal and conventional markers were used to ascertain paternity. Various banding techniques were employed to identify the origin of the extra chromosomal material as most likely a duplication-deficiency of the short arm of chromosome No. 8.

Abnormalities, Multiple↗
PubMedDate not supplied

Duchenne/Becker muscular dystrophy: correlation of phenotype by electroretinography with sites of dystrophin mutations.

The dark-adapted electroretinogram (ERG) of patients with Duchenne and Becker muscular dystrophy (DMD/BMD) shows a marked reduction in b-wave amplitude. Genotype-phenotype studies of mouse models for DMD show position-specific effects of the mutations upon the phenotype: mice with 5' defects of dystrophin have normal ERGs, those with defects in the central region have a normal b-wave amplitude associated with prolonged implicit times for both the b-wave and oscillatory potentials, and mice with 3' defects have a phenotype similar to that seen in DMD/BMD patients. The mouse studies suggest a key role for the carboxyl terminal dystrophin isoform, Dp260, in retinal electrophysiology. We have undertaken a systematic evaluation of DMD/BMD patients through clinical examination and review of the literature in order to determine whether the position-specific effects of mutations noted in the mouse are present in man. We have found that, in man, a wider variation of DMD defects correlate with reductions in the b-wave amplitude. Individuals with normal ERGs have mutations predominantly located 5' of the transcript initiation site of Dp260. Our results suggest that the most important determinant in the ERG b-wave phenotype is the mutation position, rather than muscle disease severity. Forty-six per cent of patients with mutations 5' of the Dp260 transcript start site have abnormal ERGs, as opposed to 94% with more distal mutations. The human genotype-phenotype correlations are consistent with a role for Dp260 in normal retinal electrophysiology and may also reflect the expression of other C-terminal dystrophin isoforms and their contributions to retinal signal transmission.

Dystrophin↗