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
Amino Acid Transport Systems, Neutral/genetics* ; Cornea ; Cystinosis/genetics* ; Humans ; Hypokalemia ; Infant ; Male ; Mutation ; Rare Diseases

Cystinosis, an autosomal recessively inherited lysosomal storage disease, results from impaired transport of the amino acid cystine out of cellular lysosomes. The consequent accumulation and crystallization of cystine destroys tissues, causing growth retardation, Fanconi syndrome, renal failure, eye problems, and endocrinopathies. The gene for cystinosis, CTNS, was mapped to chromosome 17p13. The diagnosis of cystinosis was made by measuring the leukocyte cystine content. The presence of typical corneal crystals on slit-lamp examination is also diagnostic. Since treatment with cysteamine has proved extremely effective, early diagnosis and treatment are critical aspects. We experienced a typical case of cystinosis in a 12-year-old boy with growth retardation.
Child ; Crystallization ; Cysteamine ; Cystine ; Cystinosis* ; Diagnosis ; Early Diagnosis ; Fanconi Syndrome ; Humans ; Leukocytes ; Lysosomal Storage Diseases ; Lysosomes ; Male

PURPOSE: We report a case of systemic cystinosis who showed cystine crystal depositions within cornea. METHODS: A 13-year-old boy with systemic cystinosis who had chronic renal failure, growth retardation, rickets for 9 years was consulted for ophthalmic examination for photophobia. We performed complete ophthalmic examinations including slit lamp examination, corneal pachymetry, corneal sensitivity test, specular microscopy, corneal topography, and fundoscopic examination. RESULTS: There were needle-like cystine crystal depositions within the entire corneal stroma. Other findings were within normal. CONCLUSIONS: We report a case of sytemic cystinosis that had cystine crystal depositions within cornea. It is the first case report in Korea.
Adolescent ; Cornea* ; Corneal Pachymetry ; Corneal Stroma ; Corneal Topography ; Cystine* ; Cystinosis* ; Humans ; Kidney Failure, Chronic ; Korea ; Male ; Microscopy ; Photophobia ; Rickets

Proximal renal tubular acidosis (RTA) is caused by a defect in bicarbonate (HCO₃⁻) reabsorption in the kidney proximal convoluted tubule. It usually manifests as normal anion-gap metabolic acidosis due to HCO₃⁻ wastage. In a normal kidney, the thick ascending limb of Henle’s loop and more distal nephron segments reclaim all of the HCO₃⁻ not absorbed by the proximal tubule. Bicarbonate wastage seen in type II RTA indicates that the proximal tubular defect is severe enough to overwhelm the capacity for HCO₃⁻ reabsorption beyond the proximal tubule. Proximal RTA can occur as an isolated syndrome or with other impairments in proximal tubular functions under the spectrum of Fanconi syndrome. Fanconi syndrome, which is characterized by a defect in proximal tubular reabsorption of glucose, amino acids, uric acid, phosphate, and HCO₃⁻, can occur due to inherited or acquired causes. Primary inherited Fanconi syndrome is caused by a mutation in the sodium-phosphate cotransporter (NaPₐ-II) in the proximal tubule. Recent studies have identified new causes of Fanconi syndrome due to mutations in the EHHADH and the HNF4A genes. Fanconi syndrome can also be one of many manifestations of various inherited systemic diseases, such as cystinosis. Many of the acquired causes of Fanconi syndrome with or without proximal RTA are drug-induced, with the list of causative agents increasing as newer drugs are introduced for clinical use, mainly in the oncology field.
Acidosis ; Acidosis, Renal Tubular ; Amino Acids ; Cystinosis ; Extremities ; Fanconi Syndrome ; Glucose ; Kidney ; Nephrons ; Sodium-Phosphate Cotransporter Proteins ; Uric Acid

Cystinosis is a rare disease characterized by abnormal lysosomal cystine accumulation of cystine due to impaired lysosomal transport. We previously reported the first case of cystinosis in Korea in a 12-year-old boy with short stature, general weakness, and photophobia. The diagnosis was confirmed based on ophthalmic findings and biochemical analyses (serum leukocyte cystine measurement). Major endocrine manifestations at diagnosis included hypothyroidism, growth retardation, and hypogonadism. Despite oral cysteamine administration and renal replacement therapy, multiple complications including both endocrine and nonendocrine disorders developed during and after adolescence. In this report, we review the presenting features and factors related to the long-term complications in a patient with cystinosis.
Adolescent* ; Child ; Cysteamine ; Cystine ; Cystinosis* ; Diagnosis ; Humans ; Hypogonadism ; Hypothyroidism ; Korea ; Leukocytes ; Lysosomal Storage Diseases ; Male ; Photophobia ; Rare Diseases ; Renal Replacement Therapy

Pediatric diseases are important because diagnosis and care for these can be complex. Among them, specific diseases have been associated with ocular involvement. This review presents the ocular manifestations of various pediatric diseases relevant to the clinician. An array of ocular manifestations of hyperthyroidism, hypoparathyroidism, diabetes mellitus, porphyria, cystinosis, mucopolysaccharidosis, Wilson disease, juvenile idiopathic arthritis, systemic lupus erythematosus, Marfan syndrome, Weill-Marchesani syndrome are described. In this review we will review ocular manifestations of systemic pediatric diseases for comprehensive understanding of eye involvement. With this review, authors can recognize the ocular manifestations for diagnosis and management of pediatric systemic diseases.
Arthritis, Juvenile ; Cystinosis ; Diabetes Mellitus ; Diagnosis ; Hepatolenticular Degeneration ; Hyperthyroidism ; Hypoparathyroidism ; Lupus Erythematosus, Systemic ; Marfan Syndrome ; Mucopolysaccharidoses ; Pediatrics ; Porphyrias ; Weill-Marchesani Syndrome