SEARCH · Search PubMed

Results for “CYSTINOSIS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources

PubMed1986

Course of nephropathic cystinosis after age 10 years.

We identified 80 patients with nephropathic cystinosis older than age 10 years in the United States and Canada. The oldest reported individual was 26 years of age. Ninety percent of patients had received at least one renal allograft. Age at the time of first transplant varied between 7 and 17 years (mean 10.0 years). Almost three fourths of the patients required thyroid replacement, 27% had splenomegaly, and 42% had hepatomegaly. Photophobia was noted in 86% of patients, decreased visual acuity in 32%, and corneal ulcerations in 15%. Neurologic involvement, renal osteodystrophy, and diabetes mellitus were unusual. All these late complications of nephropathic cystinosis contribute to a description of the natural history of the disease and provide a rationale for the therapeutic use of cystine-depleting agents after renal transplantation.

Adolescent↗

PubMed2001

Cystinosis, cataract surgery, and corneal erosions.

A 21-year-old man presented with severe corneal cystinosis and steroid-related cataract bilaterally. Rather than combined cataract surgery and penetrating keratoplasty, the patient had uneventful phacoemulsification and intraocular lens implantation after which visual acuity improved to 66 in both eyes. The outcome indicates that conventional phacoemulsification is sufficient in these cases. A guarded prognosis is advised in patients with cystinosis having cataract surgery as the fundal view is often impaired and there may be associated maculopathy.

Acrylic Resins↗

PubMed2004

Noncirrhotic portal hypertension in association with juvenile nephropathic cystinosis: case presentation and review of the literature.

We report a case of portal hypertension and oesophageal varices arising in an 18-year-old female renal transplant recipient with juvenile nephropathic cystinosis diagnosed at 6 years of age. The patient had a history of poor compliance with her prescribed cysteamine therapy. Routine examination revealed normal liver function without hepatomegaly but asymptomatic splenomegaly. An abdominal ultrasound suggested mild oesophageal varices, confirmed later on endoscopy. A liver biopsy revealed an abundance of cystine crystals within the hepatic Kupffer cells, with preserved hepatic architecture. Although the pathophysiology of this rare complication is unclear, in the absence of other aetiologies the likely cause is the patient's poorly controlled cystinosis. As cystinotic patients live longer with improved renal transplant management and cysteamine therapy, it is of interest to characterize the long-term course of the illness after renal transplantation. An understanding of the pathophysiology of hepatic dysfunction will be required to manage this potential late complication of the disease.

Adult↗

PubMed1998

A novel gene encoding an integral membrane protein is mutated in nephropathic cystinosis.

Nephropathic cystinosis, an autosomal recessive disorder resulting from defective lysosomal transport of cystine, is the most common inherited cause of renal Fanconi syndrome. The cystinosis gene has been mapped to chromosome 17p13. We found that the locus D17S829 was homozygously deleted in 23 out of 70 patients, and identified a novel gene, CTNS, which mapped to the deletion interval. CTNS encodes an integral membrane protein, cystinosin, with features of a lysosomal membrane protein. Eleven different mutations, all predicted to cause loss of function of the protein, were found to segregate with the disorder.

Amino Acid Sequence↗

PubMed1979

Evidence for cerebral involvement in nephropathic cystinosis.

Cranial computerized tomography (CCT) of 3 children with nephropathic cystinosis and chronic renal failure (CRF) revealed a hydrocephalus internus and externus. In two boys the findings consisted of bilateral dilatation of the ventricular system and of the subarachnoid space; in one boy the alterations were mainly unilateral. The children had repeated convolsions which could not be explained by deterioration of renal function. Their neurological condition was otherwise normal. In six non-cystinotic patients with chronic renal failure, CCT showed normal anatomical structures. The possibility is discussed that the hitherto unknown pathogenetic mechanism of cystinosis leads to diffuse cerebral atrophy, resulting in internal and external hydrocephalus.

Atrophy↗

PubMed1976

[Cystinosis, hyperparathyroidism and metastatic calcifications (author's transl)].

An 11-year-old boy died from uraemia in the course of cystinosis. In addition to the renal lesions common to this disease he had also developed nodular hyperplasia of the parathyroids and widespread extra-osseous calcifications in lungs, kidneys, stomach, the muscular arteries, skin and subcutaneous tissue. The calcifications and other features suggest that the hyperparathyroidism was a "tertiary" one, although this term is not generally accepted. The unusual cutaneous calcifications were probably due to calciphylaxis. As in this case, hyperparathyroidism and calcinosis can develop into a "second disease" which, due to the cystinosis, may follow a remarkably autonomous course.

Arteries↗

PubMedDate not supplied

Effect of growth hormone treatment on glucose tolerance in a patient with cystinosis after kidney transplantation.

A 16 year-old boy with nephropathic cystinosis and kidney transplantation was successfully treated with rhGH because of growth retardation. After 15 months of rhGH therapy he developed impaired glucose tolerance. Various causes like cystinosis itself, the immunosuppressive therapy with cyclosporine A and cortisone, but rhGH too might have been the responsible factors for that. Treatment with rhGH was initiated again after 4 months of interruption of therapy because no relation between impaired glucose tolerance and GH could be established.

Adolescent↗

PubMed1987

Cysteamine therapy for children with nephropathic cystinosis.

We treated 93 children with nephropathic cystinosis with oral cysteamine (mean dose, 51.3 mg per kilogram of body weight per day) for up to 73 months. This agent is known to be effective in depleting cells of cystine. In our study, the mean cystine depletion from leukocytes was 82 percent. A historical control group of 55 children received either ascorbic acid (27 children) or placebo (28). At age six, 2 of 17 controls had a serum creatinine level less than 1.0 mg per deciliter, as compared with 17 of 27 patients treated with cysteamine for at least one year (odds ratio, 12.8; 95 percent confidence interval, 2.1 to 33.9). At the end of the study, creatinine clearance was higher in the cysteamine group than in the control group (38.5 vs. 29.7 ml per minute per 1.73 m2; 95 percent confidence limits on the difference, 1.8 and 15.8), even though the cysteamine group was on average 1.4 years older than the control group. Cysteamine also improved growth; those in the cysteamine group between two and three years of age grew at 93 percent of the normal velocity, as compared with 54 percent in the control group. Fourteen percent of the patients could not tolerate the taste and smell of cysteamine. Concurrent controls treated in a blinded fashion with a placebo were not included in this study. With this limitation in mind, we conclude that oral cysteamine, by depleting cells of cystine, helps maintain renal glomerular function, improves growth, and constitutes the current treatment of choice for nephropathic cystinosis.

Administration, Oral↗

PubMed2003

The evaluation and treatment of gastrointestinal disease in children with cystinosis receiving cysteamine.

OBJECTIVES: Cysteamine prevents organ damage in children with cystinosis, but may cause gastrointestinal (GI) symptoms. In this study we evaluated the nature of GI disease, and the value of omeprazole in controlling GI symptoms in these children. STUDY DESIGN: Upper GI disease was evaluated with endoscopy, gastrin levels, and acid secretion studies after oral administration of cysteamine, before and after 16 weeks of therapy with omeprazole. A symptom score was devised. RESULTS: Eleven children (mean age, 5.7 years) were studied. After cysteamine ingestion, before and after omeprazole therapy, the mean maximum acid output was significantly higher than the mean basal acid output. The maximum acid output was measured within 60 minutes of cysteamine ingestion and was reduced by omeprazole therapy (P<.01). The mean peak gastrin level was 30 minutes postcysteamine and was higher than baseline (P<.01). The initial mean symptom score (maximum score, 14) was 6.9 and fell to 0.7 (P<.0001) after 16 weeks of omeprazole therapy. At endoscopy, two children had diffuse gastric nodularity, and nearly all had cystine crystal deposits. CONCLUSIONS: GI symptoms in children with cystinosis receiving cysteamine are often acid-mediated and improve with omeprazole. Cystine crystals were detected in the GI tract and may signify inadequate treatment with cysteamine.

Anti-Ulcer Agents↗

PubMed1999

Molecular characterization of CTNS deletions in nephropathic cystinosis: development of a PCR-based detection assay.

Nephropathic cystinosis is an autosomal recessive disorder that is characterized by accumulation of intralysosomal cystine and is caused by a defect in the transport of cystine across the lysosomal membrane. Using a positional cloning strategy, we recently cloned the causative gene, CTNS, and identified pathogenic mutations, including deletions, that span the cystinosis locus. Two types of deletions were detected-one of 9.5-16 kb, which was seen in a single family, and one of approximately 65 kb, which is the most frequent mutation found in the homozygous state in nearly one-third of cystinotic individuals. We present here characterization of the deletion breakpoints and demonstrate that, although both deletions occur in regions of repetitive sequences, they are the result of nonhomologous recombination. This type of mechanism suggests that the approximately 65-kb deletion is not a recurrent mutation, and our results confirm that it is identical in all patients. Haplotype analysis shows that this large deletion is due to a founder effect that occurred in a white individual and that probably arose in the middle of the first millenium. We also describe a rapid PCR-based assay that will accurately detect both homozygous and heterozygous deletions, and we use it to show that the approximately 65-kb deletion is present in either the homozygous or the heterozygous state in 76% of cystinotic patients of European origin.

Alleles↗

PubMed2001

Cystinosin, the protein defective in cystinosis, is a H(+)-driven lysosomal cystine transporter.

Cystinosis is an inherited lysosomal storage disease characterized by defective transport of cystine out of lysosomes. However, the causative gene, CTNS, encodes a seven transmembrane domain lysosomal protein, cystinosin, unrelated to known transporters. To investigate the molecular function of cystinosin, the protein was redirected from lysosomes to the plasma membrane by deletion of its C-terminal GYDQL sorting motif (cystinosin-DeltaGYDQL), thereby exposing the intralysosomal side of cystinosin to the extracellular medium. COS cells expressing cystinosin-DeltaGYDQL selectively take up L-cystine from the extracellular medium at acidic pH. Disruption of the transmembrane pH gradient or incubation of the cells at neutral pH strongly inhibits the uptake. Cystinosin-DeltaGYDQL is directly involved in the observed cystine transport, since this activity is highly reduced when the GYDQL motif is restored and is abolished upon introduction of a point mutation inducing early-onset cystinosis. We conclude that cystinosin represents a novel H(+)-driven transporter that is responsible for cystine export from lysosomes, and propose that cystinosin homologues, such as mammalian SL15/Lec35 and Saccharomyces cerevisiae ERS1, may perform similar transport processes at other cellular membranes.

Amino Acid Motifs↗

PubMed1990

Central nervous system involvement in nephropathic cystinosis.

Nephropathic cystinosis, an autosomal recessive lysosomal storage disorder due to impaired cystine transport, causes damage to multiple organs that results in end-stage renal disease, hypothyroidism, and retinopathy, usually in childhood. Dialysis and renal transplantation now frequently enable patients with cystinosis to live into adulthood. Examinations at autopsy of a 28-year-old man who died of complications of this disease showed deposits of cystine crystals in multiple organs. There was severe cerebral involvement with multifocal cystic necrosis, dystrophic calcification, spongy change, and vacuolization that had produced profound neurologic deficits. Electron microscopy of the brain documented cytoplasmic deposition of cystine crystals in membrane bound vacuoles within the cytoplasm of pericytes and within parenchymal cells of the white matter. While affected patients who have received renal transplants may no longer die from renal failure, serious, potentially life-threatening, neurologic complications of this disorder may supervene.

Adult↗

PubMed2002

Immunolocalization of cystinosin, the protein defective in cystinosis.

Cystinosis is an autosomal recessive disorder associated with excessive lysosomal cystine accumulation secondary to defective lysosomal cystine efflux. CTNS, the gene mutated in cystinosis, codes for the lysosomal membrane protein cystinosin. Antisera were raised in rabbits to a carboxy-terminal oligopeptide sequence from cystinosin. Antisera were screened by Western blotting and immunocytochemical analyses of transfected COS-7 cells expressing either human wild-type cystinosin, a wild-type cystinosin-green fluorescent protein (GFP) fusion protein, or a fusion protein of GFP and mutant human cystinosin with a carboxy-terminal deletion. In Western blots, bands corresponding to cystinosin or cystinosin-GFP were observed in transfected cells but no signal was detected in cells expressing the carboxy-terminal mutant; preimmune sera yielded negative results in all three cases. In transfected cells expressing wild-type cystinosin, immunoreactivity appeared in subcellular vesicles. In cells expressing the wild-type cystinosin-GFP fusion protein, immunoreactivity colocalized with GFP fluorescence. Previous studies demonstrated that GFP fluorescence from this construct colocalized with immunostaining for a known lysosomal membrane protein, i.e., lysosome-associated membrane protein 2. In immunohistochemical analyses, cystinosin localized to tubule epithelia in three normal human kidneys, with a pattern similar to that of lysosome-associated membrane protein 2; cystinosin immunoreactivity was absent in kidneys from patients with a CTNS deletion. For the first time, antisera have been raised that localize cystinosin in cells in vitro and in vivo.

Adult↗

PubMed1981

Prenatal diagnosis of nephropathic cystinosis. Pregnancy at risk ascertained through heterozygote diagnosis of parents.

The biochemical diagnosis of cystinosis in a deceased girl was made indirectly through the demonstration of heterozygote values of free-cystine contents in leukocytes from both parents. Amniocentesis was performed on the mother in the 16th week of two subsequent pregnancies. Amniotic fluid cell lysate from the first fetus had 6-8 times normal levels of radioactivity in the cystine band determined by a 35S-cystine pulse labeling method followed by high voltage electrophoresis on paper. Values for the cystine contents in various organs of the affected fetus are given. The second fetus was found to be not affected, and this was subsequently confirmed by the birth of a healthy child. The results of the laboratory analyses in these two cases were available to the parents 21 and 23 days following amniocentesis, respectively. The interruption of the first pregnancy was performed in the 19th week. This was 4 and 6 weeks earlier, respectively, than in the two previously reported induced abortions of affected fetuses, and should increase the acceptability of the present method for prenatal diagnosis of nephrophatic cystinosis.

Amniocentesis↗

PubMed1982

Cystine transport is defective in isolated leukocyte lysosomes from patients with cystinosis.

The activity of a cystine transport system in lysosomes prepared from the leukocytes of patients with cystinosis was found to be deficient. In normal subjects, this system was resistant to N-ethylmaleimide and demonstrated saturation kinetics. Lysosomes from individuals heterozygous for cystinosis demonstrated a reduced maximum velocity for cystine egress from lysosomes. The rate of cystine escape from normal lysosomes was enhanced by adenosine triphosphate. The availability of normal and mutant lysosomes provides a means of investigating mechanisms of amino acid transport across lysosomal membranes.

Biological Transport↗

PubMed1978

Hypothyroidism in children with cystinosis.

Eight children with cystinosis (3 with renal transplants, 2 on maintenance haemodialysis, 2 with chronic renal failure, and one with normal renal function) were studied for evidence of hypothyroidism, and compared with a control group of children with chronic renal failure due to other causes. Abnormal thyroid function was present in all the cystinotic patients: thyroxine (T4) low in 1, free thyroxine index (FTI) low in 2, thyroid-stimulating hormone (TSH) raised in 6; all had a supranormal TSH response to thyrotrophin-releasing hormone (TRH) stimulation, indicating impaired thyroid reserve compared with patients in the control group who had a depressed or normal TSH response. Increased growth velocity with thyroid supplementation occurred in only 2 patients, and the onset of puberty may have contributed to this improvement. Hypothyroidism is a common finding in cystinosis, and it is suggested that thyroxine treatment be started when the TSH concentration becomes raised.

Adolescent↗

PubMed1982

Effect of indomethacin on clinical progress and renal function in cystinosis.

Three children with nephropathic cystinosis were treated with indomethacin 3 mg/kg a day for periods ranging from 9 to 18 months. The drug produced worthwhile clinical improvement in all, with marked beneficial effects on polyuria, polydipsia, and general wellbeing. Clearance studies performed under conditions of maximal water diuresis showed that proximal tubular sodium reabsorption was increased in all children, with consequent reduction in sodium delivery to the distal nephron leading to reduced free water clearance and distal tubular cation exchange. Plasma sodium and potassium concentrations became normal in all patients, with improvement in phosphate and bicarbonate concentrations in one. Renal function continued to deteriorate, but without obvious acceleration of the process by the drug. We were unable to demonstrate a beneficial effect on growth; nevertheless, indomethacin is a useful adjunct to the symptomatic treatment of children with severe nephropathic cystinosis.

Body Water↗

PubMed1981

Adolescent cystinosis: a clinical and specular microscopic study of an unusual sibship.

Six members of a sibship originally consisting of 8 offspring lived to teenage. Five of these developed the adolescent form of cystinosis. Since adolescent cystinosis is autosomal recessive, such a high incidence of affected members is of uncommon occurrence. Depending on whether the sibship size (n) is known as 6 to 8, it should occur only in approximately 1.5% or 5.8% of sibships of corresponding size. Specular microscopy was used to study the corneal stroma of all 3 of the living, affected members of this sibship and the conjunctiva of one of the siblings. Vivid, needle-shaped crystals were observed in the corneal stroma. Smaller, variably shaped crystals were observed in the conjunctiva. The crystals seen with specular microscopy fit the description of those studied with light and electron microscopy.

Adolescent↗