Human and animal fertility studies in cystinosis reveal signs of obstructive azoospermia, an altered blood-testis barrier and a subtherapeutic effect of cysteamine in testis.

Cystinosis is an inherited metabolic disorder caused by autosomal recessive mutations in the CTNS gene leading to lysosomal cystine accumulation. The disease primarily affects the kidneys followed by extra-renal organ involvement later in life. Azoospermia is one of the unclarified complications which are not improved by cysteamine, which is the only available disease-modifying treatment. We aimed at unraveling the origin of azoospermia in cysteamine-treated cystinosis by confirming or excluding an obstructive factor, and investigating the effect of cysteamine on fertility in the Ctns-/- mouse model compared with wild type. Azoospermia was present in the vast majority of infantile type cystinosis patients. While spermatogenesis was intact, an enlarged caput epididymis and reduced levels of seminal markers for obstruction neutral α-glucosidase (NAG) and extracellular matrix protein 1 (ECM1) pointed towards an epididymal obstruction. Histopathological examination in human and mouse testis revealed a disturbed blood-testis barrier characterized by an altered zonula occludens-1 (ZO-1) protein expression. Animal studies ruled out a negative effect of cysteamine on fertility, but showed that cystine accumulation in the testis is irresponsive to regular cysteamine treatment. We conclude that the azoospermia in infantile cystinosis is due to an obstruction related to epididymal dysfunction, irrespective of the severity of an evolving primary hypogonadism. Regular cysteamine treatment does not affect fertility but has subtherapeutic effects on cystine accumulation in testis.

Emerging New Diagnostic Modalities and Therapies of Nonalcoholic Fatty Liver Disease.

PURPOSE OF REVIEW: Nonalcoholic fatty liver disease (NAFLD) has emerged as the leading cause of chronic liver disease in both adults and children. In this article, we review recent developments in the screening, diagnosis, and treatment of pediatric NAFLD. RECENT FINDINGS: Although alanine aminotransferase (ALT) remains the best screening test for NAFLD in children, and liver biopsy is still required for the diagnosis of nonalcoholic steatohepatitis (NASH), other noninvasive biomarker/imaging studies (MRI-PDFF and VCTE) have emerged as diagnostic methods for pediatric NAFLD. Two large clinical therapeutic trials testing vitamin E, metformin, and cysteamine in pediatric NAFLD yielded mostly inconclusive results. Bariatric surgery has begun to be used in adolescents with severe obesity. An adult phase 2 study using obeticholic acid (OCA) to treat NASH patients with fibrosis showed some positive results. As we continue to await the first FDA-approved therapeutic agent for NASH, lifestyle change remains the main modality of treatment. Newer diagnostic and treatment modalities for pediatric NAFLD continue to be in development under FDA guidance.

Ocular manifestations of intermediate cystinosis: To treat or not to treat?

PURPOSE: To report a case of intermediate cystinosis with an atypical presentation in which a delayed non-treatment decision has been proved right over a large period of time. METHODS: This is a unique case report of a patient who underwent full ophthalmologic evaluations including anterior chamber optical coherence tomography on a regular basis during a 7-year follow-up period. RESULTS: A 30-year-old woman with photophobia was being studied by the Department of Nephrology with a suspicion of Alport syndrome. Slit-lamp examination showed iridescent deposits throughout the corneal anterior stroma and the inferior tarsal conjunctiva bilaterally. Anterior chamber optical coherence tomography showed stromal hyperreflectivity. CTNS gene was found to be positive for c.416C>T (Ser139Phe) mutation. The patient was offered oral and topical cysteamine which was refused. After a period of 5 years of follow-up, general health status remained stable, corneal disease showed no progression and photophobia complaints diminished. However, the patient was advised to start systemic and topical cysteamine because of the unknown development of the disease. CONCLUSION: In this reported case, a delayed non-treatment decision has been proved right contrary to published evidence of active treatment of photophobia. The decision whether to treat or not to treat corneal involvement of the disease is not straightforward. Besides biomicroscopic evaluations, patients' complaints and expectations should be taken into account.

CTNS mRNA molecular analysis revealed a novel mutation in a child with infantile nephropathic cystinosis: a case report.

BACKGROUND: Cystinosis is an autosomal recessive lysosomal storage disorder characterized by accumulation of cystine in lysosomes throughout the body. Cystinosis is caused by mutations in the CTNS gene that encodes the lysosomal cystine carrier protein cystinosin. CTNS mutations result in either complete absence or reduced cystine transporting function of the protein. The diagnosis of nephropathic cystinosis is generally based on measuring leukocyte cystine level, demonstration of corneal cystine crystals by the slit lamp examination and confirmed by genetic analysis of the CTNS gene. CASE PRESENTATION: A boy born to consanguineous Caucasian parents had the characteristic clinical features of the infantile nephropathic cystinosis including renal Fanconi syndrome (polydipsia/polyuria, metabolic acidosis, hypokalemia, hypophosphatemia, low molecular weight proteinuria, glycosuria, cystine crystals in the cornea) and elevated WBC cystine levels. Initially we performed RFLP analysis of the common in the Northern European population 57-kb deletion of proband's DNA, then a direct Sanger sequencing which revealed no mutations in the coding part of the CTNS gene. To confirm the diagnosis we performed RT-PCR analysis of total RNA obtained from patient-derived fibroblasts in combination with cDNA sequencing. This revealed the skipping of exon 4 and exon 5 in the CTNS in our patient. Therefore, we detected a novel 9-kb homozygous deletion in the CTNS gene at genomic DNA level, spanning region from intron 3 to intron 5. In order to identify the inheritance pattern of the deletion we analyzed DNA of proband's mother and father. Both parents were found to be heterozygous carriers of the CTNS mutation. CONCLUSIONS: Analysis of CTNS gene transcript allowed to identify a large homozygous deletion in the patient with infantile nephropathic cystinosis. Mutational detection at RNA level may be an efficient tool to establish the genetic defect in some cystinosis patients.

Therapeutic Problems and Pregnancy in a Patient With Infantile Nephropathic Cystinosis: A Case Report.

BACKGROUND: Cystinosis is a rare genetic disorder characterized by the abnormal accumulation of cystine in the lysosomes of various tissues and organs leading to their dysfunction. The most common type is the infantile nephropathic cystinosis which without treatment leads to renal failure and before the introduction of cysteamine was the cause of death before puberty. CASE PRESENTATION: A 27-year-old female patient with infantile cystinosis developed end-stage renal disease at the age of 10. The first kidney transplantation from patient's father was carried out at the age of 12. The recurrent urinary tract infections led to the graft failure after 6 years. Following the removal of right appendages due to the ovarian tumor, the patient underwent the second kidney transplantation from her mother at the age of 19. After the transplantation, the cysteamine treatment was irregular due to limited availability of the medicine. When it became regular in 2017 the patient did not tolerate full doses. Despite elevated blood levels of cystine and the removal of right appendages, the patient naturally became pregnant in August 2017. Except for recurrent urinary tract infections, the renal parameters remained normal throughout the entire pregnancy. However, in the 32nd week of gestation, due to preeclampsia a caesarean section was performed. A healthy daughter was born, 1400/41 and with a 9 point Apgar score. CONCLUSIONS: Due to the possibility of treatment with cysteamine and kidney transplantations, patients with cystinosis live longer and their quality of life improves. These female patients can even naturally become pregnant and give birth to healthy children.

Carbon Black Tinted Contact Lenses for Reduction of Photophobia in Cystinosis Patients.

PURPOSE: To examine if current development on using contact lenses for drug delivery of cysteamine to treat ocular symptoms of cystinosis can be tinted to mitigate photophobia common in patients by reducing transmittance Methods: Commercial contact lenses were placed in a carbon black solution to examine loading after lens synthesis. Silicone hydrogel contact lenses were also synthesized with carbon black added prior to UV curing. Transmittance was measured using UV-vis spectrophotometry over the range of 190-1190 nm and compared to unmodified contact lenses. Lens parameters of refractive index, ion permeability, and Young's modulus were measured using a refractometer, release of sodium chloride, and the cantilever method. Cysteamine release was measured by loading lenses into 5% cysteamine solution and then monitoring the release of the drug using UV-vis spectrophotometry. Vitamin E diffusion barriers were also added to lenses via ethanol solution, and the release of cysteamine from these modified lenses was also examined. RESULTS: No leeching of carbon black was detected during experiments. Loading of pre-made contact lenses led to uneven distribution of carbon black throughout lens. Adding 0.3% carbon black to lens monomer solution prior to UV-curing led to even distribution and a transmittance reduction of approximately 50%. Ion permeability was reduced from 6.19 ± 0.90 x 10-3 to 1.28 ± 0.06 x 10-3 mm2 min-1, and Young's modulus was decreased from 1.58 ± 0.08 to 1.29 ± 0.06 MPa. Cysteamine releases from carbon black lenses with and without vitamin E were comparable to controls, although the loading solution of vitamin E/ethanol had to be tripled to achieve a similar mass loading to control. CONCLUSIONS: Carbon black increases the softness of contact lenses, but a loading of 0.3% maintains lens parameters required for wear. The release of cysteamine is also possible with carbon black lenses, albeit requiring a higher loading concentration of vitamin E to achieve similar release times.

[Nephropatic cystinosis: report of one case]. / Cistinosis nefropática: caso clínico que ilustra diagnóstico molecular.

Nephropatic cystinosis (NC) is a rare disease associated with pathogenic variants in the CTNS gene, with a common variant that consists of a 57kb-deletion involving CTNS. Patients with NC that are treated with cysteamine improve their life quality and expectancy. We report a 12-month-old girl with a poor growth rate since the 4th month of life. She was admitted to the Hospital with acute kidney injury, severe dehydration and metabolic acidosis. She was treated with volume restorative and bicarbonate. Proximal tubulopathy and Fanconi's syndrome was diagnosed. Medical treatment improved renal function that was stabilized in stage 4 chronic kidney disease (CKD). Since infantile NC was suspected, CTNS genetic analysis was considered. Genomic DNA was isolated from peripheral blood to perform PCR for exons 3-12 in CTNS gene and for the specific 57kb-deletion PCR. Afterwards, variant segregation analysis was performed in the familiar trio. The genetic analysis showed that the patient was homozygous for the common 57kb-deletion encompassing CTNS that had been inherited from her asymptomatic heterozygous parents. The molecular confirmation allowed genetic counselling for parents and facilitated the access to cysteamine. Oral treatment with cysteamine resulted in improvement of renal function to CKD stage 3. After 16 months of treatment the patient shows metabolic stability and mild recovery of height. Ophthalmologic follow-up detected ocular cystine crystals 12 months after diagnosis, starting cysteamine drops.

[Cystinosis : Diagnosis, cystine-depleting therapy, and transition]. / Cystinose : Diagnostik, cystinentspeichernde Therapie und Transition.

This article presents a case of cystinosis in a young man. Diagnosis of the disease and the problem of transition to adult care are described. Cystinosis is a rare lysosomal storage disease with first manifestation in early childhood presenting as renal Fanconi syndrome. Without treatment, the disease leads to severe health impairment. Due to the rarity of the disease, a correct diagnosis is often delayed. Without treatment, cystinosis often leads to end-stage renal failure, blindness, hypothyroidism, diabetes mellitus, and rickets. Cystine-depleting therapy with cysteamine significantly improves mortality and quality of life.

Cistinosis nefropática: caso clínico que ilustra diagnóstico molecular / Nephropatic cystinosis: report of one case

Nephropatic cystinosis (NC) is a rare disease associated with pathogenic variants in the CTNS gene, with a common variant that consists of a 57kb-deletion involving CTNS. Patients with NC that are treated with cysteamine improve their life quality and expectancy. We report a 12-month-old girl with a poor growth rate since the 4th month of life. She was admitted to the Hospital with acute kidney injury, severe dehydration and metabolic acidosis. She was treated with volume restorative and bicarbonate. Proximal tubulopathy and Fanconi's syndrome was diagnosed. Medical treatment improved renal function that was stabilized in stage 4 chronic kidney disease (CKD). Since infantile NC was suspected, CTNS genetic analysis was considered. Genomic DNA was isolated from peripheral blood to perform PCR for exons 3-12 in CTNS gene and for the specific 57kb-deletion PCR. Afterwards, variant segregation analysis was performed in the familiar trio. The genetic analysis showed that the patient was homozygous for the common 57kb-deletion encompassing CTNS that had been inherited from her asymptomatic heterozygous parents. The molecular confirmation allowed genetic counselling for parents and facilitated the access to cysteamine. Oral treatment with cysteamine resulted in improvement of renal function to CKD stage 3. After 16 months of treatment the patient shows metabolic stability and mild recovery of height. Ophthalmologic follow-up detected ocular cystine crystals 12 months after diagnosis, starting cysteamine drops.

Diagnostic accuracy of magnetic resonance imaging hepatic proton density fat fraction in pediatric nonalcoholic fatty liver disease.

We assessed the performance of magnetic resonance imaging (MRI) proton density fat fraction (PDFF) in children to stratify hepatic steatosis grade before and after treatment in the Cysteamine Bitartrate Delayed-Release for the Treatment of Nonalcoholic Fatty Liver Disease in Children (CyNCh) trial, using centrally scored histology as reference. Participants had multiecho 1.5 Tesla (T) or 3T MRI on scanners from three manufacturers. Of 169 enrolled children, 110 (65%) and 83 (49%) had MRI and liver biopsy at baseline and at end of treatment (EOT; 52 weeks), respectively. At baseline, 17% (19 of 110), 28% (31 of 110), and 55% (60 of 110) of liver biopsies showed grades 1, 2, and 3 histological steatosis; corresponding PDFF (mean ± SD) values were 10.9 ± 4.1%, 18.4 ± 6.2%, and 25.7 ± 9.7%, respectively. PDFF classified grade 1 versus 2-3 and 1-2 versus 3 steatosis with areas under receiving operator characteristic curves (AUROCs) of 0.87 (95% confidence interval [CI], 0.80, 0.94) and 0.79 (0.70, 0.87), respectively. PDFF cutoffs at 90% specificity were 17.5% for grades 2-3 steatosis and 23.3% for grade 3 steatosis. At EOT, 47% (39 of 83), 41% (34 of 83), and 12% (10 of 83) of biopsies showed improved, unchanged, and worsened steatosis grade, respectively, with corresponding PDFF (mean ± SD) changes of -7.8 ± 6.3%, -1.2 ± 7.8%, and 4.9 ± 5.0%, respectively. PDFF change classified steatosis grade improvement and worsening with AUROCs (95% CIs) of 0.76 (0.66, 0.87) and 0.83 (0.73, 0.92), respectively. PDFF change cut-off values at 90% specificity were -11.0% and +5.5% for improvement and worsening. CONCLUSION: MRI-estimated PDFF has high diagnostic accuracy to both classify and predict histological steatosis grade and change in histological steatosis grade in children with NAFLD. (Hepatology 2018;67:858-872).

In vitro drug release and in vivo safety of vitamin E and cysteamine loaded contact lenses.

Cystinosis is an orphan disease caused by a genetic mutation that leads to deposition of cystine crystals in many organs including cornea. Ophthalmic manifestation of the disease can be treated with hourly instillation of cysteamine eye drops. The hourly eye drop instillation is tedious to the patients leading to poor compliance and additionally, significant degradation of the drug occurs within one week of opening the bottle, which further complicates this delivery approach. This paper focuses on designing a contact lens to treat the disease with improved efficacy compared to eye drops, and also exploring safety of the drug eluding contact lens in an animal model. Our goal is to design a lens that is safe and that can deliver a daily therapeutic dose of cysteamine to the cornea while retaining drug stability. We show that cysteamine diffuses out rapidly from all lenses due to its small size. Vitamin E incorporation increases the release duration of both ACUVUE®OASYS® and ACUVUE® TruEyeTM but the effect is more pronounced in TruEyeTM likely due to the low solubility of vitamin E in the lens matrix and higher aspect ratio of the barriers. The barriers are not effective in hydrogel lenses, which along with the high aspect ratio in silicone hydrogels suggests that barriers could be forming at the interface of the silicone and hydrogel phases. The presence of vitamin E has an additional beneficial effect of reduction in the oxidation rates, likely due to a transport barrier between the oxygen diffusing through the silicone channels and drug located in the hydrogel phase. Based on this study, both Acuvue®OASYS® and ACUVUE® TruEyeTM can be loaded with vitamin E to design a cysteamine eluting contact lenses for effective therapy of cystinosis. The lenses must be worn for about 4-5 hr. each day, which is less than the typical duration of daily-wear. The vitamin E and cysteamine loaded lenses did not exhibit any toxicity in a rabbit model over a period of 7-days.

Emerging Treatments for Nonalcoholic Fatty Liver Disease and Nonalcoholic Steatohepatitis.

This review discusses completed phase II randomized clinical trials with high-quality published results for compounds that demonstrate effects on nonalcoholic steatohepatitis histology (obeticholic acid, elafibranor, and liraglutide). The authors also review the available preliminary data on cenicriviroc and selonsertib, with or without simtuzumab's phase II studies. Finally, the authors briefly discuss compounds that have been tested but did not achieve the primary end point of histologic improvement and appeared in high-quality published articles (cysteamine bitartrate and long-chain polyunsaturated fatty acids).

In Children With Nonalcoholic Fatty Liver Disease, Cysteamine Bitartrate Delayed Release Improves Liver Enzymes but Does Not Reduce Disease Activity Scores.

BACKGROUND & AIMS: No treatment for nonalcoholic fatty liver disease (NAFLD) has been approved by regulatory agencies. We performed a randomized controlled trial to determine whether 52 weeks of cysteamine bitartrate delayed release (CBDR) reduces the severity of liver disease in children with NAFLD. METHODS: We performed a double-masked trial of 169 children with NAFLD activity scores of 4 or higher at 10 centers. From June 2012 to January 2014, the patients were assigned randomly to receive CBDR or placebo twice daily (300 mg for patients weighing ≤65 kg, 375 mg for patients weighing >65 to 80 kg, and 450 mg for patients weighing >80 kg) for 52 weeks. The primary outcome from the intention-to-treat analysis was improvement in liver histology over 52 weeks, defined as a decrease in the NAFLD activity score of 2 points or more without worsening fibrosis; patients without biopsy specimens from week 52 (17 in the CBDR group and 6 in the placebo group) were considered nonresponders. We calculated the relative risks (RR) of improvement using a stratified Cochran-Mantel-Haenszel analysis. RESULTS: There was no significant difference between groups in the primary outcome (28% of children in the CBDR group vs 22% in the placebo group; RR, 1.3; 95% confidence interval [CI], 0.8-2.1; P = .34). However, children receiving CBDR had significant changes in prespecified secondary outcomes: reduced mean levels of alanine aminotransferase (reduction, 53 ± 88 U/L vs 8 ± 77 U/L in the placebo group; P = .02) and aspartate aminotransferase (reduction, 31 ± 52 vs 4 ± 36 U/L in the placebo group; P = .008), and a larger proportion had reduced lobular inflammation (36% in the CBDR group vs 21% in the placebo group; RR, 1.8; 95% CI, 1.1-2.9; P = .03). In a post hoc analysis of children weighing 65 kg or less, those taking CBDR had a 4-fold better chance of histologic improvement (observed in 50% of children in the CBDR group vs 13% in the placebo group; RR, 4.0; 95% CI, 1.3-12.3; P = .005). CONCLUSIONS: In a randomized trial, we found that 1 year of CBDR did not reduce overall histologic markers of NAFLD compared with placebo in children. Children receiving CBDR, however, had significant reductions in serum aminotransferase levels and lobular inflammation. ClinicalTrials.gov no: NCT01529268.

Controversies and research agenda in nephropathic cystinosis: conclusions from a "Kidney Disease: Improving Global Outcomes" (KDIGO) Controversies Conference.

Nephropathic cystinosis is an autosomal recessive metabolic, lifelong disease characterized by lysosomal cystine accumulation throughout the body that commonly presents in infancy with a renal Fanconi syndrome and, if untreated, leads to end-stage kidney disease (ESKD) in the later childhood years. The molecular basis is due to mutations in CTNS, the gene encoding for the lysosomal cystine-proton cotransporter, cystinosin. During adolescence and adulthood, extrarenal manifestations of cystinosis develop and require multidisciplinary care. Despite substantial improvement in prognosis due to cystine-depleting therapy with cysteamine, no cure of the disease is currently available. Kidney Disease: Improving Global Outcomes (KDIGO) convened a Controversies Conference on cystinosis to review the state-of-the-art knowledge and to address areas of controversies in pathophysiology, diagnostics, monitoring, and treatment in different age groups. More importantly, promising areas of investigation that may lead to optimal outcomes for patients afflicted with this lifelong, systemic disease were discussed with a research agenda proposed for the future.

Pancytopenia in a patient with cystinosis secondary to myelosuppression from cystine crystal deposition: a case report.

INTRODUCTION: Cystinosis is a rare metabolic genetic disorder caused by a mutation in the cystinosin lysosomal cystine transporter gene. Clinically, it is characterized by systemic accumulation of cystine crystals in tissues causing end-organ dysfunction in the kidney, eyes, muscles, and other organs in the body. In very rare cases, it can also involve the bone marrow and the resulting cystine crystal deposition can cause myelosuppression leading to pancytopenia. CASE PRESENTATION: Here we report the case of a 26-year-old white woman with cystinosis and other complex medical comorbidities who developed pancytopenia. She was worked up extensively and ruled out for common causes of pancytopenia (infectious disorders, vitamin deficiencies secondary to gastrointestinal malabsorption, rheumatologic, and hematologic disorders). On bone marrow biopsy she was found to have extensive deposits of cystine crystals, which was thought to be the cause of her myelosuppression leading to her pancytopenia. As a result, by treating her underlying cystinosis more aggressively we were able to observe an improvement in her pancytopenia a few months afterwards. CONCLUSIONS: Pancytopenia secondary to myelosuppression from cystine crystal deposition in the bone marrow is a very rare complication that has been reported in only a handful of case reports. This case illustrates the importance of keeping a broad differential diagnosis and systematically ruling out common causes of pancytopenia. It also demonstrates the importance of bone marrow biopsies in the evaluation of unexplained pancytopenia.

[Cystinosis in adults: A systemic disease]. / La cystinose chez l'adulte : une maladie systémique.

Cystinosis is a multisystemic autosomal recessive disorder characterized by an intra-lysosomal accumulation of cystine. It is due to a defect of cystine transport through the membrane of the lysosome. The classical infantile form is characterized by a proximal tubulopathy, corneal cystine crystals and progressive renal failure, leading to end stage renal disease before 20 years of age in 90% of cases in historical cohorts. It is the most common cause of Fanconi syndrome in children. Due to recent progress in renal transplantation and to the specific treatment with cysteamine, patients survival improved significantly in the last years and adult nephrologists take care of such patients. However, disease evolution is characterized by other complications: endocrinological (hypothyroidism, diabetes, male hypogonadism), neuromuscular and of the central nervous system. Cysteamine delays the onset of these complications. A multidisciplinary team should take care of these patients, even if the nephrologist remains in first line. Apart from infantile form, there is a juvenile form, with a later onset, and an adult form, which may be only ocular, although renal involvement may be associated. The aim of this revue is to summarize actual knowledge of the disease to provide guidance to adult nephrologist to take care of his patients.

Mood and illness experiences of adults with cystinosis.

BACKGROUND: Cystinosis is an autosomal recessive disorder with an estimated incidence of 1/100,000-200,000 live births. The main complications are renal disease, visual impairment, endocrine abnormalities and growth retardation. OBJECTIVE: Our aim was to describe the mood and illness experiences of adults with cystinosis. METHODS: Twenty-three patients attending the adult cystinosis clinic at Guy's Hospital, London were asked to complete the Hospital Anxiety and Depression Scale (HADS) questionnaire anonymously. Eighteen months later, 21 patients who were still alive were invited to participate in a semi-structured interview aimed at exploring illness experience. RESULTS: Eighteen patients completed the HADS questionnaire (means: depression = 7.2; anxiety = 9.2), and 12 participated in the interviews. Three significant themes emerged: (i) the main physical complaints were tiredness, the impact of short stature and side effects of cysteamine medication, especially halitosis, poor taste and nausea. (ii) Cystinosis has a major impact on relationships, autonomy and social life, including reliance on families for support to self-manage, distress at dependence, social anxiety, reduced social involvement and some positive effects on family cohesiveness. (iii) Patients use a range of individual coping strategies to deal with their illness and medication. CONCLUSIONS: Adult cystinosis patients reported comparatively high-anxiety and depression scores. Common complaints related to the complications of cystinosis and the side-effects of cysteamine, which impacted on relationships, autonomy and social life. Patients described a wide range of strategies, including benefit finding, for coping with cystinosis.

Cysteamine (Cystagon®) adherence in patients with cystinosis in Spain: successful in children and a challenge in adolescents and adults.

BACKGROUND: Cysteamine has improved survival and prognosis in cystinosis. Increasing numbers of patients reach adulthood and face new challenges such as compliance that wanes over time. The aim of this study was to evaluate adherence to cysteamine treatment in a group of cystinotic patients in Spain in an attempt to identify potential therapy pitfalls and improve the overall care of affected individuals. Despite the impact of cysteamine on prognosis, there is a paucity of data regarding adherence. METHOD: Thirty-four cystinotic patients (21 male) 38% ≥18 years were enrolled in a voluntary, anonymous survey. Replies were obtained from patients (15/34), mothers (11/34), fathers (4/34) and both parents (4/34). RESULTS: Patient age (median and interquartile range) at diagnosis was 1 year (0.57-1), and patient age at Cystagon® initiation was also 1 year (0.8-1.8). Sixteen (47%) were kidney transplant (KTx) recipients; six were retransplanted. Age at first KTx 10 years (8.7-13.7). Patient understanding of multiorgan involvement in cystinosis: 4.1 organs reported; eye 97% and kidney 91%. Cysteamine was given by mother (100%) and father (83%) in <11 year olds, or self-administered (94%) in ≥11 year olds. Four daily doses in 89% versus 56% in <11 year olds or ≥11 year olds, with fixed schedule in 94% versus 50% in <11 or ≥11 year olds and progressive loss of reminders over time. Furthermore, 44% complained of unpleasant smell. Motivation for treatment compliance was 100% versus 40% in <11 versus ≥11 year olds, respectively. Disease impact in patients <18 years is as follows: school (29%), social (14%), 'feeling different' (10%); in patients ≥18 years: 'feeling different' (62%), professional (39%) and job absenteeism (31%). Referring physician: paediatric nephrologist (94%) and nephrologist (63%) in <11 versus ≥11 year olds. Ophthalmological follow-up: 83% versus 38% in <11 versus ≥11 year olds. Patient opinion of physician expertise: paediatric nephrologist (94%) and nephrologist (44%). New treatment options (65%) and better information (42%) were demanded to improve adherence. CONCLUSION: Treatment with Cystagon is effective in young patients. However, adherence diminishes over time in adolescents and adults despite disease impact. Strategies such as better information on the disease, patient self-care promotion and facilitated transition to adult healthcare services are required to improve compliance and the clinical management of cystinosis.

Cystinosis: renal glomerular and renal tubular function in relation to compliance with cystine-depleting therapy.

BACKGROUND AND OBJECTIVES: Nephropathic cystinosis is a lysosomal storage disorder characterized by renal tubular Fanconi syndrome in infancy and glomerular damage leading to renal failure at ∼10 years of age. Therapy with the cystine-depleting agent cysteamine postpones renal failure, but the degree of compliance with this treatment has not been correlated with preservation of kidney function. METHODS: We assessed leucocyte cystine depletion by cysteamine and created the composite compliance score that incorporates the extent of leucocyte cystine depletion, as well as duration of cysteamine treatment, into a single integer. Age at renal failure was used to gauge preservation of renal function, and the Fanconi syndrome index (FSI), a measure of aminoaciduria, was used to assess renal tubular Fanconi syndrome. RESULTS: Age at renal failure varied directly and linearly with the composite compliance score (y = 0.3x +8.8; R(2) = 0.61). The slope indicated that for every year of excellent cystine depletion, nearly 1 year of renal function was preserved. Age at renal failure correlated roughly with mean leucocyte cystine level, but not with mean cysteamine dosage. There was no correlation between the FSI and the composite compliance score. CONCLUSIONS: Greater compliance with oral cysteamine therapy yields greater preservation of renal glomerular, but not tubular, function. Oral cysteamine therapy should be given at the maximum tolerated dose, within the recommended limits.