Cystinosis, Nephropathic

Alternative Names

  • CTNS
  • Lysosomal Cystine Transport Protein, Defect of
  • Cystinosin, Defect of
  • Cystinosis, Infantile Nephropathic
  • Cystinosis, Atypical Nephropathic

Associated Genes

Cystinosin
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WHO-ICD-10 version:2010

Endocrine, nutritional and metabolic diseases

Metabolic disorders

OMIM Number

219800

Mode of Inheritance

Autosomal recessive

Gene Map Locus

17p13.2

Description

Nephropathic cystinosis is a lysosomal storage disorder characterised by the build-up of cystine in cells, which leads to progressive organ failure. Clinically, nephropathic cystinosis presents with Fanconi syndrome between 6 and 12 months of age showing signs of fluid and electrolyte loss, aminoaciduria, glycosuria, phosphaturia, renal tubular acidosis, rickets and growth retardation. Untreated cases progress to end-stage renal failure in the first decade of life. A rare late-onset form of cystinosis occurs in older children, manifesting at age 10 to 12 years with proteinuria due to glomerular damage, as opposed to tubular damage that occurs in infantile cystinosis. Adults with 'benign' cystinosis have asymptotic corneal cystine deposition but do not have progressive renal damage.

Mutations in CTNS gene, which encodes cystinosin is associated with nephropathic cystinosis.

Epidemiology in the Arab World

View Map
Subject IDCountrySexFamily HistoryParental ConsanguinityHPO TermsVariantZygosityMode of InheritanceReferenceRemarks
219800.1.1ArabUnknownYes Renal tubular acidosis; Growth delay;...NM_004937.3:c.18_21delHomozygousAutosomal, RecessiveShahkarami et al. 2013 Patient 'P4' in the ...
219800.2ArabUnknownYes Renal tubular acidosis; Growth delay...NM_004937.3:c.923G>AHomozygousAutosomal, RecessiveShahkarami et al. 2013 Patient 'P5' in the ...
219800.3ArabUnknownNo Renal tubular acidosis; Growth delay;...NM_004937.3:c.681G>A, NM_004937.3:c.1015G>AHeterozygousAutosomal, RecessiveShahkarami et al. 2013 Compound heterozygou...
219800.4ArabUnknownNo Renal tubular acidosis; Growth delay...NM_004937.3:c.681G>A, NM_004937.3:c.1015G>AHeterozygousAutosomal, RecessiveShahkarami et al. 2013 Compound heterozygou...
219800.5MoroccoUnknownNo Growth delay; Corneal crystals; Abnorm...NM_004937.3:c.922G>AHomozygousAutosomal, RecessiveMacías-Vidal et al. 2009 Patient 'CY1' in the...
219800.6MoroccoUnknownNo Renal Fanconi syndromeNM_004937.3:c.61+5G>AHomozygousAutosomal, RecessiveMacías-Vidal et al. 2009 Patient 'CY34' in th...
219800.7MoroccoUnknownNo Renal Fanconi syndrome; Polyuria; Grow...NM_004937.3:c.922G>AHeterozygousAutosomal, RecessiveMacías-Vidal et al. 2009 Patient 'CY47' in th...
219800.8MoroccoUnknownNo Glycosuria; Polyuria; VomitingNM_004937.3:c.61+5G>AHomozygousAutosomal, RecessiveMacías-Vidal et al. 2009 Patient 'CY55' in th...
219800.9Saudi ArabiaUnknown Renal insufficiency; Corneal crystalsNM_004937.3:c.922G>AHomozygousAutosomal, RecessiveAldahmesh et al. 2009 Patient 'CTNS-F8-1' ...
219800.10United Arab EmiratesUnknown Renal insufficiency; Specific learning ...NM_004937.3:c.681G>AHomozygousAutosomal, RecessiveAl-Jasmi et al. 2013
219800.11United Arab EmiratesUnknownNM_004937.3:c.681+1G>AHomozygousAutosomal, RecessiveBen-Rebeh et al. 2012
219800.G.1ArabUnknownYes Renal tubular acidosis; Growth delay; ...NM_004937.3:c.681G>AHomozygousAutosomal, RecessiveShahkarami et al. 2013 8 patients of Arab o...
219800.G.2.1Saudi ArabiaUnknown Renal insufficiency; Corneal crystalsNM_004937.3:c.422C>THomozygousAutosomal, RecessiveAldahmesh et al. 2009 5 patients with cyst...
219800.G.2.2Saudi ArabiaUnknown Renal insufficiency; Corneal crystalsNM_004937.3:c.530A>G, NM_004937.3:c.1013T>GHeterozygousAutosomal, RecessiveAldahmesh et al. 2009 2 patients with cyst...
219800.G.2.3Saudi ArabiaUnknown Renal insufficiency; Corneal crystalsNM_004937.3:c.681G>AHomozygousAutosomal, RecessiveAldahmesh et al. 2009 3 patients with cyst...
219800.G.2.4Saudi ArabiaUnknown Renal insufficiency; Corneal crystalsNM_004937.3:c.562-1G>CHomozygousAutosomal, RecessiveAldahmesh et al. 2009 2 patients with cyst...
219800.G.2.5Saudi ArabiaUnknown Renal insufficiency; Corneal crystalsNM_004937.3:c.1013T>GHomozygousAutosomal, RecessiveAldahmesh et al. 2009 6 patients with cyst...

Other Reports

Egypt

Soliman et al. (2009) screened 33 patients from 24 Egyptian families for nephropathic cystinosis. Patients were suspected on the basis of presentation with proximal renal tubular acidosis and/or hypophosphatemic rickets, and chronic kidney disease, particularly in families reporting death of siblings due to a similar condition. In addition, siblings of index cases were also screened. Slit lamp examination for corneal cystine crystals was used to screen children above two years of age and WBC cystine assay was used to confirm the diagnosis in children below 2 years of age. Cystinosis was confirmed in 16 patients from 15 families. Diagnosed patients included eight boys and eight girls with a mean age at diagnosis of 52.7 ± 39.2 months (10-112 months). Parents were consanguineous in 12 families (80%) and sibling deaths were reported in six families (40%). Soliman et al. (2009) suggest that slit lamp examination is a simple and reasonably sensitive method for diagnosis of nephropathic cystinosis above 2 years.

Palestine

Abou-Chaaban et al. (1997) studied the pattern of pediatric renal diseases among children in the Dubai Emirate during the period from 1991 to 1996. In this period, a total of 712 pediatric patients were seen with various renal problems. Abou-Chaaban et al. (1977) observed five Palestinian patients with cystinosis with renal involvement. All these patients developed chronic renal failure. Abou-Chaaban et al. (1997) noted that children of Palestinian origin had the highest prevalence of cystinosis and that all affected children had consanguineous parents.

[Abou-Chaaban M, Al Murbatty B, Abdul Majid M. Spectrum of pediatric renal diseases in Dubai. Saudi J Kidney Dis Transplant. 1997; 8(3):310-3.]

Saudi Arabia

Moammar et al. (2010) reviewed all patients diagnosed with inborn errors of metabolism (IEM) from 1983 to 2008 at Saudi Aramco medical facilities in the Eastern province of Saudi Arabia. During the study period, 165530 Saudi infants were born, of whom a total of 248 newborns were diagnosed with 55 IEM. Affected patients were evaluated based on clinical manifestations or family history of similar illness and/or unexplained neonatal deaths. Almost all patients were born to consanguineous parents. Lysosomal storage disorders were the most diagnosed category of IEM in this cohort (74 out of 248 cases, 30%). Among them, one case was found to have cystinosis with an estimated incidence of 1 per 100,000 live births. All cases of lysosomal storage disorders were confirmed by enzyme assay on skin fibroblasts, liver biopsy or leukocytes. The authors concluded that data obtained from this study underestimate the true figures of various IEM in the region. Therefore, there is an urgent need for centralized newborn screening program that utilizes tandem mass spectrometry, and offers genetic counseling for these families.

United Arab Emirates

Abou-Chaaban et al. (1997) studied the pattern of pediatric renal diseases among children in the Dubai Emirate during the period from 1991 to 1996. In this period, a total of 712 pediatric patients, including 230 nationals of the United Arab Emirates, were seen with various renal problems. Abou-Chaaban et al. (1997) observed two Emirati patients with cystinosis with renal involvement. All these patients developed chronic renal failure. The patients either expired or underwent cadaveric kidney transplantation.

Al-Jasmi et al. (2013) studied the prevalence of lysosomal storage diseases (LSDs) in the UAE and reported their mutation spectrum. This study included all the patients diagnosed and followed up between 1995 and 2010 at the only two metabolic referral centers in the country. In this period, a total of 119 patients, 65 of them Emiratis, were diagnosed with LSDs. One Emirati patient with Cystinosis was identified in this study, giving a birth prevalence of 0.25 per 100,000 for Emiratis.

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