Congenital complex chromosome rearrangements (CCR) compatible with life are rare in man. Thus patients with CCR usually present considerable diagnostic difficulties both clinically and cytogenetically. We studied a 12-year-old mentally retarded male with minor congenital anomalies as described below and his first-degree relatives. The propositus had an unbalanced karyotype with eight break points and seven derivative chromosomes; two deletions, del(6) (q25----qter) and del(14) (q31----qter), and four translocations, t(2;11), t(5;15), t(6;11), t(6;20) were present. Parental chromosomes were normal; however, the mother had a few metaphases with abnormal chromosomes suggestive of chromosome instability. These findings and a review of reported patients with CCR are presented with regard to speculations about etiology, pathogenesis, phenotypic expression, and prognosis. Physicians should be aware of CCR and broader indications for cytogenetic studies appear warranted in view of these data.
Galactokinase is an essential enzyme in the metabolism of galactose. Patients with deficiencies in galactokinase exhibit early‐onset cataracts. We examined the sequence of the human galactokinase gene (GK1) from 13 patients exhibiting galactokinase deficiency and identified 12 novel mutations. One of the mutations occurred in six of the 13 probands examined, and the remaining 11 were unique mutations. Expression of each of the mutant GK1 genes in Xenopus oocytes resulted in very low galactokinase activity levels. These results provide important information regarding the types of GK1 mutations that occur in the human population. Hum Mutat 15:447–453, 2000. © 2000 Wiley‐Liss, Inc.
Citrullinemia-is one of several human diseases caused by a defect in the Krebs-Henseleit urea cycle. In this disorder a deficiency of liver argininosuccinate synthetase has been reported.' 1\Iorrow and his colleagues have recently described an infant with this condition2 and a fibroblast-like cell line has been derived from a skin biopsy of this child. In studying minimal media requirements for heteroploid human cell cultures, Eagle observed that citrulline, but not ornithine, could substitute for arginine as an essential nutrient.3 This evidence for the existence of the citrulline to arginine portion of the Krebs-Henseleit cycle had also been noted in cultured chick embryo heart fibroblasts.4 We have found that extracts of diploid fibroblast-like cells cultured from human skin normally can convert citrulline to arginine, but not ornithine to citrulline (ornithine transcarbamylase) or arginine to urea (arginase).5 We have compared the growth requirements and the properties of argininosucciinate synthetase in normal human cells and cells cultured from the skin of an infant vith citrullinernia. Our findings provide evidence for the genetic nature of this human disorder. Methods and Material.-Procedure for cell culture: Fibroblast-like cell lines were established from skin biopsies of human subjects and were subcultured in monolayers according to the procedure of Hayflick and Moorhead.6 Control lines were from three different human subjects and the citrullinemia cell line was derived from the skin of a 4-month-old female with citrullinemia ("citrullinemia cells"). The complete medium included 0.2 mAl arginine and was made up of 90% (v/v) double-strength Eagle's basal medium in Earle's balanced salt solution and 10% (v/v) fetal calf serum. For arginine-free medium a special preparation of Eagle's amino acid concentrate without arginine was used (Flow Laboratories, Rockville, Md.). Because the arginine-free medium contains 10% fetal calf serum, the final medium described as "arginine-free" does contain some arginine (approximately 2 JAM). Penicillin (100 units/ml), streptomycin (100 ,Pg/ml), and aureomycin (50 ,4g/ml) were added to the medium. The aureomycin was effective in pre
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.