Cystinosis induced by / 中国当代儿科杂志

A boy, aged 1 year and 6 months, was found to have persistent positive urine glucose at the age of 4 months, with polydipsia, polyuria, and growth retardation. Laboratory examinations suggested that the boy had low specific weight urine, anemia, hypokalemia, hyponatremia, hypomagnesemia, metabolic acidosis, glycosuria, acidaminuria, increased fractional excretion of potassium, and decreased tubular reabsorption of phosphate. X-ray examinations of the head, thorax, and right hand showed changes of renal rickets. The slit-lamp examination showed a large number of cystine crystals in the cornea. The genetic testing showed a suspected pathogenic homozygous mutation of the

Nephropathic cystinosis presenting with uveitis: Report of a “Can't See, Can't Pee” situation

Nephropathic cystinosis is a rare autosomal recessive lysosomal disease characterized by accumulation of pathognomonic cystine crystals in renal and other tissues of the body. Cystinosis is caused by mutant cystinosin, the cystine transport protein located in lysosomal membranes, leading to systemic deposits of cystine and resultant end organ damage. Cystinosis is rarer in Asians than Caucasians with only a handful of cases reported from India to date. Due to its extreme rarity and clinically insidious presentation in contrast to the infantile form, the diagnosis of juvenile nephropathic cystinosis is frequently delayed or overlooked. Moreover, routine processing and sectioning of paraffin embedded tissues dissolves cystine crystals, making it difficult to diagnose this condition on light microscopic examination alone, mandating electron microscopic (EM) analysis of renal biopsies for an accurate diagnosis of this condition. We describe a case of juvenile nephropathic cystinosis presenting with uveitis and photophobia in a 17-year-old Indian male, diagnosed after EM examination of the patient's renal biopsy for evaluation of nephrotic syndrome. While highlighting the diagnostic utility of EM, we describe a few histopathologic clues which can prompt inclusion of EM analysis of renal biopsies in this setting.

Progress of diagnosis and treatment for Gitelman syndrome and cystinosis / 中华实用儿科临床杂志

Gitelman syndrome(GS) is an autosomal recessive,salt-losing tubulopathy resulted from inactivating mutations in the SLCl2A3 gene that encodes the Thiazine diuretic sensitive sodium chloride cotransporter (NCCT).GS is characterized by hypokalemic metabolic alkalosis,hypomagnesemia and hypocalciuria.Diagnosis of GS is relied on the clinical symptoms,biochemical abnormalities and genetic test.All GS patients are suggested to keep high-sodium diet.Magnesium and potassium supplements are usually given to GS patients for lifelong to improve clinical symptoms.Individual management of GS includes health education,complication evaluation and regular follow-up with annual evaluation by a nephrologist.Cystinosis is a rare autosomal-recessive lysosomal storage disease caused by inactivating mutations in the CTNS gene that encodes the lysosomal cystine transporter,cystinosin,resulting in the accumulation of cystine within the lysosome.There are 3 clinical forms of cystinosis:infantile or early-onset nephropathic cystinosis,juvenile or late-onset nephropathic cystinosis and adult or ocular cystinosis.Diagnosis of cystinosis is based on the CTNS genetic test.Early diagnosis and early cystine-depleting therapy with cysteamine is essential to prevent or attenuate end-organ damage and improve overall prognosis.

CTNS gene mutation leads to cysteine nephropathy combined with corneal crystal in young child / 临床儿科杂志

Objective To explore the diagnosis of cystinosis.Methods The clinical and biochemical information, and gene detection results in a child with cystinosis was retrospective analyzed.Results Four-year-old female presented with photophobia and corneal crystal was found by ophthalmic examination at 2 years old, bilateral kidney stone was found, accompanied by development delay and rickets at 3 years old. Gas chromatography analysis in urine showed that a variety of amino acids were increased, and urine sugar and urinary micro-protein were also increased, which were in accordance with fanconi syndrome. The blood free carnitine was decreased, ester acyl carnitine spectrum was normal, and multi-amino acids such as lysine, valine and arginine were decreased. Gene analysis showed a homozygous mutation of c.696C>G (p.323 N>K) inCTNS gene, which was a known mutation. Both her parents were carrier of heterozygous mutation of c.696C>G inCTNS gene.Conclusion Child with kidney stone, renal damage, combined by multi-system damage such as eyes, bone, and thyroid should be paid attention to identify the cystinosis.

A Recent Experience in an Egyptian Medical Center: Strategies for the Clinical and Genetic Diagnoses of Nephropathic Cystinosis.

Aims: To screen cases of infantile cystinosis among different forms of proximal renal tubular acidosis (RTA). Study Design: Cross sectional. Place and Duration of Study: From a total of 25 families of RTA followed up in Nephrology unit of Mansoura University Children's Hospital (MUCH), Egypt, two unrelated families were diagnosed as infantile nephropathic cystinosis using clinical suspicion plus mutation analysis of CTNS gene in the period between January 2008 and November 2012. Methodology: Two families with multiple cases of infantile nephropathic cystinosis have been diagnosed. In absence of high-performance liquid chromatography and tandem mass spectrometry used for measuring intraleucocyte cystine, diagnostic tools for cystinosis used in the current work were clinical and laboratory evidences of PRTA, slit lamp detection of corneal cystine crystals and finally identification of CTNS gene mutations. All patients were subjected to routine echocardiography because of accidental discovery of heart malformation in one case. Rare mutant variant of the first family was subjected to RNA analysis which unfortunately failed, alternatively an in silico study was used to predict splice site. Results: All patients with cystinosis manifested a severe clinical course. Proband of family 1 showed two known mutations; deletion in the exon 3 (c.18_21 del GACT) and substitution in acceptor splice site of intron 11 (c.971 -12G>A). In silico study predicted an anticipated splice site that modified the open reading frame in carboxy-terminal region. Probands of family 2 were affected by ventricular and atrial septal defects in younger, and mild mitral and aortic incompetence in older patient; their DNA analysis revealed a novel nonsense mutation (c.734 G>A) which caused a premature stop codon in position 245 of protein. Conclusion: Nephropathic cystinosis has been diagnosed with ease in Egyptian population without need of sophisticated investigations. A novel mutation had been added to the list of CTNS gene variants.