PubMed Health⌕ Search

Biomedical subjects

J Charrow

Publications and source records attributed to J Charrow.

12 recordsLinked to original sources
PubMed1992

Emergence of optic pathway gliomas in children with neurofibromatosis type 1 after normal neuroimaging results.

We report the appearance of gliomas of the optic nerve or chiasm in four young children with neurofibromatosis type 1 whose previous neuroimaging studies showed no abnormalities; the age range of the children was 1 year 8 months to 5 years 9 months at the time the tumors were detected. Normal neuroimaging findings in an infant or young child with neurofibromatosis type 1 does not provide assurance that the optic nerves and chiasm will remain healthy.

Child, Preschool↗
PubMed1991

Autosomal recessive cerebellar hypoplasia and endosteal sclerosis: a newly recognized syndrome.

We describe a brother and sister and an unrelated boy with congenital cerebellar hypoplasia and endosteal sclerosis. All 3 children presented with ataxia and developmental delay, and were found to have microcephaly, short stature, oligodontia, strabismus, nystagmus, and congenital hip dislocation. A previously published case is reviewed. The disorder appears to represent a newly recognized autosomal recessive syndrome.

Cerebellum↗
PubMed1990

When is a test result abnormal? Defining limits and risks.

Test results from "normal" and "non-normal" individuals frequently overlap. Individuals with test results near the region of overlap have a high risk of being misdiagnosed. We present a statistical method for quantifying the certainty of diagnoses and defining a normal range, and illustrate its application with a specific example from a Tay-Sachs disease carrier screening program. This method can be applied to any test result based on a continuous variable and is particularly well suited to screening programs where the risk or incidence of a disease is known. We use an inconclusive range to reduce the likelihood of incorrect diagnoses resulting from measurement error and borderline results. The limits of the normal, inconclusive, and nonnormal ranges are based on three considerations: (1) the probability of misdiagnoses, (2) the expected frequency of inconclusive diagnoses, and (3) the reproducibility of the test results.

Bayes Theorem↗
PubMed1989

Optic gliomas in children with neurofibromatosis type 1.

To determine the frequency and natural history of tumors of the optic nerves and chiasm in patients with neurofibromatosis type 1, we obtained computed tomographic scans of 65 children who had no known visual or ocular abnormalities before their initial evaluation. Optic gliomas were detected in 10 children (15%). The median age of children with gliomas was 4.3 years (mean 5.8 years, range 9 months to 21 years). Three children (30%) had isolated, unilateral tumors, three (30%) had bilateral tumors, and four (40%) had involvement of the optic chiasm and of one or both nerves. Definite abnormalities of vision were found in only two children (20%). Five additional children were referred to the clinic after evaluation of ophthalmologic complaints led to the diagnosis of neurofibromatosis type 1: three had unilateral exophthalmos and two had plexiform neurofibromas of the eyelid with associated glaucoma. Ipsilateral optic gliomas were found in all five children; one child also had a contralateral tumor. Optic gliomas are commonly identified in young children with neurofibromatosis type 1 who have no ocular or visual abnormalities. Optic nerve gliomas may be associated with plexiform neurofibromas of the eyelid and glaucoma.

Adolescent↗
PubMed1988

Biochemical abnormalities in rhizomelic chondrodysplasia punctata.

Biochemical studies with emphasis on peroxisomal functions were conducted in six patients with well-documented rhizomelic chondrodysplasia punctata (RCDP) and compared with findings in patients with Zellweger syndrome and neonatal adrenoleukodystrophy (ALD). Patients with RCDP had three characteristic biochemical abnormalities: (1) profound defect in plasmalogen (ether lipid) synthesis, which is significantly greater than the analogous defect in Zellweger syndrome or neonatal ALD; (2) reduction of phytanic acid oxidation activity to 1% to 5% of control, similar to that observed in Refsum disease, Zellweger syndrome, and neonatal ALD; (3) presence of the unprocessed form of peroxisomal 3-oxoacyl-coenzyme A thiolase in the postmortem liver of two patients. Other peroxisomal functions were normal, including levels of very long chain fatty acids, pipecolic acid, and bile acid intermediates, and immunoblot studies of peroxisomal acyl-CoA oxidase and bifunctional enzyme in postmortem liver. Unlike what is observed in Zellweger syndrome and neonatal ALD, catalase activity in cultured skin fibroblasts was sedimentable, indicating that peroxisome structure is not grossly deficient in RCDP. The biochemical abnormalities in RCDP were consistent and set it apart from all the other known peroxisomal disorders.

Acetyl-CoA C-Acyltransferase↗
PubMed1987

Uncombable hair (pili trianguli et canaliculi): evidence for dominant inheritance with complete penetrance based on scanning electron microscopy.

Uncombable or spun-glass hair (pili trianguli et canaliculi) is an uncommon condition in which the hair is "unmanageable" and has a distinct appearance on scanning electron microscopy. The hair is usually grossly abnormal in infancy and childhood, but may become normal later in life. Although dominant inheritance has been observed, most cases have been sporadic. Both recessive and dominant transmission with incomplete penetrance have been suggested as modes of inheritance. We report the occurrence of this condition in a young girl, her brother, and her father. Although the proposita and her brother had characteristically uncombable hair, their father appeared normal and denied any history of hair abnormality. However, the characteristic hair morphology was observed on scanning electron microscopy in all 3 relatives, documenting dominant transmission and complete penetrance of the gene in this family.

Child, Preschool↗
PubMed1986

Ganglioside loading of cultured fibroblasts: a provocative method for the diagnosis of the GM2 gangliosidoses.

Confirmation of deficient beta-hexosaminidase activity in suspected cases of GM2 gangliosidosis may be difficult with available assay systems if the residual activity is high (as in many juvenile cases and genetic compounds). Hexosaminidase activity is normal in the AB-variant (activator protein deficiency), although GM2-ganglioside (GM2) catabolism is severely impaired. We therefore examined ganglioside degradation in intact fibroblasts in culture. Intracellular ganglioside levels were determined in cultured human skin fibroblasts grown in standard tissue culture medium or medium supplemented with mixed bovine brain gangliosides. Cellular uptake and catabolism of the added gangliosides were manifested by modest increases in the intracellular concentrations of gangliosides GT + GD and GM1 in all cells tested, and marked accumulation of GM2 in fibroblasts from patients with GM2 gangliosidoses. Intracellular GM2 increased five- to fifteen-fold in all of the GM2 gangliosidosis cell lines tested, including those from patients with infantile Tay-Sachs disease (TSD), Sandhoff disease, late infantile and juvenile variants of TSD with high residual enzyme activity, adult onset GM2 gangliosidosis, and the AB-variant. Significant GM2 accumulation did not occur in fibroblasts from patients with GM2 gangliosidosis grown in standard medium, or in normal fibroblasts grown in ganglioside enriched medium. Our method of ganglioside feeding employs commercially available materials and no special equipment. It should be useful for the confirmation of impaired GM2 catabolism in a variety of settings.

Cells, Cultured↗
PubMed1985

Late onset GM2 gangliosidosis: an alpha-locus genetic compound with near normal hexosaminidase activity.

A non-Jewish child with late onset GM2 gangliosidosis is described. Tissues from the patient had near normal hexosaminidase A (hex A) activity using 4-methylumbelliferyl-2-acetamido-2-deoxy-beta-D-glucopyranoside (MU-glcNAc) as substrate, and deficient activity when assayed with the 6-sulphate derivative of MU-glcNAc (MU-glcNAcS) or GM2 in the presence of activator. We present evidence that this patient is a genetic compound for different alpha-subunit mutations. The father's tissues have hex A activity in the heterozygote range when assayed with MU-glcNAcS, but normal activity using MU-glcNAc; the mother's tissues have activities toward both substrates in the heterozygote range. These results emphasize the pitfalls of using only MU-glcNAc for the diagnosis of unusual variants of GM2 gangliosidosis.

Acetylglucosamine↗