Biochemical and Molecular Medicine
Regular ArticleFine Mapping of the Cystinosis Gene Using an Integrated Genetic and Physical Map of a Region within Human Chromosome Band 17p13
Abstract
The cystinosis gene has been reported to reside in a 3.1 cM region of chromosome 17p13 flanked by markers D17S1828 and D17S1798. We created a yeast artificial chromosome (YAC) contig between these markers and report here an integrated genetic and physical map which will aid in the identification of other genes in this area. Using one pertinent YAC clone, 898A10, we identified new polymorphic markers in the cystinosis gene region. One such marker, D17S2167, was localized by radiation hybrid analysis to within 10.2 cR8000of D17S1828. Haplotype analysis in two separate informative families revealed recombination events which placed the cystinosis gene between markers D17S1828 and D17S2167, an area estimated to be 187–510 kb in size. This dramatic narrowing of the cystinosis gene region permits the creation of a P1 or cosmid contig across the area of interest. The ultimate cloning of the cystinosis gene should eventually reveal how a functional lysosomal transport protein is synthesized, targetted, processed, and integrated into the lysosomal membrane.
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Nonneoplastic Diseases of the Testis
2020, Urologic Surgical PathologyChanges in our understanding of pathology have accelerated in recent years. The ability to approach a diagnostic problem from different points of view—clinical, morphologic, and molecular genetic—has led to an integrative approach to pathology. Nontumoral pathology of the testis has not been an exception. In this chapter, we start from a histophysiologic base that includes the development of the testicle, the descent of the prepubertal testis, and the adult testicle. The chapter continues with congenital anomalies of the testis and the alterations in sexual development, the classifications for which have not been uniformly accepted by those who study these matters. We focus on the undescended testis, a source of controversy regarding its best treatment—surgical versus hormonal. The problem of the infertile patient is addressed, bearing in mind not only the primary alterations, be these chromosomal or molecular, but also considering that efficient testicular function is only acquired when there is a harmonious interaction between different glands and organs. Vascular pathology of the testis is always interesting, whether focusing on a dramatic situation such as testicular torsion, or considering the relationship between varicocele and infertility. In the section on Inflammation and Infection, besides the classical processes, other lesser known processes are included in the section Other Testicular and Epidydima Lesions. Compared with the previous edition, this chapter incorporates a significant number of figures that properly document the text.
Molecular analysis of the CTNS gene in Jordanian families with nephropathic cystinosis
2015, NefrologiaNephropathic cystinosis is an autosomal recessive lysosomal storage disorder that is characterised by the accumulation of the amino acid cystine in several body tissues due to a mutation in the CTNS gene, which encodes the cystinosin protein. The aim of this study was to sequence the coding exons of the CTNS gene in five different Jordanian families and one family from Sudan with nephropathic cystinosis.
Probands initially presented with Fanconi syndrome symptoms. An eye examination showed the accumulation of cystine crystals in the cornea by the age of 2 years, suggesting cystinosis. All of the coding exons and flanking intronic sequences and the promoter region of the CTNS gene were amplified using polymerase chain reaction and subjected to sequencing.
None of the probands in this study carried the European 57-kb deletion in the CTNS gene. Seven variants in the coding and promoter sequence of the CTNS gene were identified in the probands of this study. Two of these variants were a CTNS mutation that was previously identified in a heterozygous genotype in two different patients of European descendant. The two mutations were c.829dupA in exon 10 and c.890G>A in exon 11. The proband of family 2 was compound-heterozygous for the two mutations.
This study is the first molecular study of infantile nephropathic cystinosis in Jordan. We successfully identified the causative CTNS mutations in Jordanian families. The results provide a basis for the early detection of the disease using molecular tools in a highly consanguineous Jordanian population.
La cistinosis nefropática es una enfermedad de almacenamiento lisosómico autosómica recesiva que se caracteriza por la acumulación del aminoácido cistina en varios tejidos del cuerpo. Ello se debe a una mutación en el gen CTNS, que codifica la proteína cistinosina. El objetivo de este estudio fue secuenciar los exones codificantes del gen CTNS en cinco familias jordanas afectadas por la cistinosis.
Los casos índice se presentaron inicialmente con síntomas del síndrome de Fanconi. Exámenes oftalmológicos revelaron la acumulación de cristales de cistina en la córnea a la edad de 2 años, lo que sugería la existencia de cistinosis. Todos los exones codificantes, las secuencias intrónicas flanqueantes y la región promotora del gen CTNS se amplificaron mediante reacción en cadena de la polimerasa y fueron objeto de secuenciación.
Ninguno de los casos índice de este estudio presentaba la deleción 57-kb europea en el gen CTNS. Se identificaron siete variantes en las secuencias codificante y promotora del gen CTNS en los casos índice de este estudio. Dos de estas variantes eran una mutación del gen CTNS previamente identificada en un genotipo heterocigótico de dos pacientes de descendencia europea. Las dos mutaciones eran c.829dupA en el exón 10 y c.890G>A en el exón 11. El caso índice de la familia número 2 era heterocigótico compuesto respecto a las dos mutaciones.
El presente estudio es el primer estudio molecular sobre cistinosis nefropática infantil en Jordania. Logramos identificar con éxito las mutaciones en el gen CTNS causante en familias jordanas. Los resultados sirven de base para la detección precoz de esta enfermedad mediante herramientas moleculares en una población jordana marcadamente consanguínea.
Specific Cognitive Deficits in Young Children with Cystinosis: Evidence for an Early Effect of the Cystinosin Gene on Neural Function
2007, Journal of PediatricsInfantile nephropathic cystinosis is associated with a specific cognitive deficit in visual spatial processing in older children and adults. The cause of this deficit is unknown. This study was designed to determine whether the cognitive deficit is present in young children with cystinosis, suggesting an early effect of the genetic disorder on brain development.
Young children (n = 25; age, 3-8 years) with cystinosis and 25 matched control subjects underwent cognitive testing, including tests of intelligence, visual perceptual, visual spatial, and visual motor functions.
Children with cystinosis performed significantly more poorly on tests of visual spatial and visual motor function than did control subjects. Visual perceptual abilities were equivalent in the 2 groups.
The same pattern of visual spatial deficit is present in young children with cystinosis as has previously been demonstrated in older children and adults, which suggests that there may be an influence of the cystinosis gene on brain development, rather than an adverse effect of prolonged cystine accumulation in the brain during childhood.
Cystinosis: Diagnostic through the measurement of the leukocyte cystine content by HPLC
2004, Medicina ClinicaLa cistinosis es una enfermedad autosómica recesiva caracterizada por una acumulación de cistina en el interior de los lisosomas. Existen 3 formas de la enfermedad, la infantil, la juvenil y la ocular no nefropática, clasificadas según la gravedad de los síntomas y la edad de inicio. El conocimiento de las manifestaciones clínicas tempranas y el inicio de un tratamiento adecuado retrasan la evolución de la enfermedad y mejoran las condiciones generales. Por ello es necesario desarrollar un método diagnóstico sensible para la detección temprana y el tratamiento de la enfermedad.
Se determinó el contenido de cistina intraleucocitaria mediante cromatografía líquida de alta resolución (HPLC), en una paciente de 42 años de edad que había recibido un trasplante renal y presentaba las características clínicas de la cistinosis intermedia. Se realizó asimismo el estudio molecular de posibles alteraciones estructurales en el gen de la cistinosina (CTNS), tanto en la paciente como en los miembros de la familia
Mediante la determinación del contenido de cistina intraleucocitaria en la paciente y los miembros familiares, se encontró a 5 miembros de la familia heterocigotos para la enfermedad. Este resultado se confirmó posteriormente con el análisis molecular, que mostró la presencia de la deleción de aproximadamente 65 kb en todos ellos. La paciente fue heterocigota para dicha deleción, pero la segunda alteración no se determinó
La determinación del contenido de cistina de leucocitos polimorfonucleares, que es un método útil de diagnóstico de cistinosis, permite detectar a los individuos heterocigotos
Cystinosis is an autosomal recessive disorder characterized by an accumulation of intralysosomal cystine. Three disease forms exist, infantile, juvenile or late-onset, and ocular nonnephropathic cistinosis, delineated on the basis of severity of symptoms and age of onset. The knowledge of early clinic manifestations and the onset of the appropriate therapy delay the evolution of the disease and improve the general conditions. Therefore, it is necessary to develop a sensible diagnostic method for early detection and treatment of the disease
The leukocyte cystine content was determined by HPLC in a 42 years old female patient after renal transplantation, and with the clinical characteristic complications of the intermediate cystinosis. Equally, the molecular characterization of the structural defects of the cystinosin (CTNS) gene was made in the patient and in all family members
By measuring of the leukocyte cystine content in the patient and family members, we have determined 5 family members as heterozygous. This result was confirmed by molecular analysis that showed the ˜65 kb deletion in the 5 family members. The patient was heterozygous for the ˜65 kb deletion, and the second alteration was not determined
We presented a useful diagnostic method, based in the determination of cystine content of polymorphonuclear leukocytes, which permits to detect the heterozygous individuals
Expression and genetic analysis of XIAP-associated factor 1 (XAF1) in cancer cell lines
2000, GenomicsX-linked inhibitor of apoptosis protein (XIAP) is a potent modulator of programmed cell death. XIAP specifically binds and inhibits the function of caspase-3, -7, and -9, key effector proteases of apoptosis. We recently isolated, by yeast two-hybrid screening, a novel 34-kDa zinc finger protein, XIAP-associated factor 1 (XAF1). Both the caspase inhibiting and the anti-apoptotic abilities of XIAP were found to be blocked by overexpressed XAF1. Here, we report the isolation and characterization of the human XAF1 gene. The xaf1 gene consists of seven exons spanning 18 kb. Fluorescence in situ hybridization analysis localized the xaf1 locus at 17p13.2, telomeric to the p53 gene. The xaf1 locus was further refined to YAC 746C10, approximately 3 cM distal to TP53. Microsatellite analysis of the xaf1 locus using the NCI 60 cell line panel revealed significantly decreased heterozygosity at all three polymorphic markers tested, suggesting that allelic loss of the xaf1 gene is prevalent in cancer cell lines. Examination of the same NCI cell line panel for xaf1 RNA expression demonstrated that cancer cell lines exhibited very low levels of mRNA relative to normal human liver. In contrast, XIAP mRNA levels were relatively high in the majority of cancer cell lines tested. We propose that a high level of XIAP to XAF1 expression in cancer cells may provide a survival advantage through the relative increase of XIAP anti-apoptotic function.
Corneal crystals in nephropathic cystinosis: Natural history and treatment with cysteamine eyedrops
2000, Molecular Genetics and MetabolismAlthough renal disease is the most prominent feature of the lysosomal storage disease cystinosis, corneal cystine crystal formation remains a major complication, leading to photophobia, corneal erosions, and keratopathies. Moreover, the extent of corneal crystal accumulation reflects the course and severity of the disease itself, and the cornea is accessible to direct examination. Therefore, we employed a scoring system, based on a library of slit-lamp photographs of corneas with increasing crystal densities (0.00–3.00), to assess the degree of crystal accumulation in 170 patients with nephropathic cystinosis examined at the National Institutes of Health between 1976 and 2000. None of the patients had received topical cystine-depleting therapy at the time of the evaluation. In this natural history study, infants in the first year of life had absent or minimal corneal crystals, i.e., a corneal cystine crystal score (CCCS) of 0 or 0.25. However, the CCCS increased linearly with age, such that every patient had visible crystals by 16 months of age, and plateaued at approximately 3.00 by early adolescence. Longitudinal studies in representative patients support the cross-sectional results. Individuals homozygous for the common 57-kb deletion involving the cystinosis gene (CTNS) displayed the same course of corneal crystal accumulation as did individuals not bearing the large deletion. Patients with ocular or nonnephropathic cystinosis had CCCSs that were, in general, half those expected for patients with nephropathic cystinosis of the same age. Administration of 0.55% cysteamine eyedrops, given 6 to 12 times per day, dissolved corneal cystine crystals in 10 representative patients with nephropathic cystinosis aged 1 to 32 years within 8 to 41 months.