A 1-year-ten-month-old girl, first issue of a non-consanguineous marriage was referred to us for further care. The child was born full term, with birth weight of 3.5 kg. She was noticed to have polyuria, polydipsia, photophobia and failure to thrive from 6 months of age. On evaluation, she was detected to have renal insufficiency at the age of 9 months (blood urea 93.5 mg/dL, serum creatinine 2.1 mg/dL). Renal ultrasound was normal and slit lamp examination of the eyes was suggestive of cystinosis. The patient was started on conservative management of chronic renal failure.

At presentation, the patient weighed 6.2 kg (expected 12 kg). She had fair skin, sparse hypopigmented hair, pallor and clinical evidence of rickets. She was able to sit independently and walked with support. Investigations revealed features suggestive of proximal tubular dysfunction like glucosuria, natriuria, phosphaturia and aminoaciduria; hemoglobin level 7g/dL, peripheral smear showed normocytic hypochromic red cells, blood urea 109 mg/dL and serum creatinine 2 mg/dL. Creatinine clearance by Schwartz formula was 18.42 mL/min/1.73m2, serum sodium 137 mEq/L, potassium 5.5 mEq/L, calcium 9.6 mg/dL, phosphate 4.4 mg/Dl and alkaline phosphatase 407 U/L. Arterial blood gas showed uncompensated normal anion gap metabolic acidosis. Liver function tests and thyroid function tests were normal. Auditory evaluation was normal. On ultra sound, right kidney measured 4.8 cm and left kidney 5.1 cm with loss of corticomedullary differentiation. X-ray of the wrist showed rachitic changes. Slit lamp examination revealed pigmented mottling in the mid-peripheral fundus with anterior segment showing crystalline deposits allover cornea, more in the periphery, consistent with the diagnosis of cystinosis (Fig. 1). The patient received a high salt intake, calcium, vitamin D, iron and bicarbonate supplements (Shohl’s solution). Dietary advice for higher caloric and protein intake was given.

Fig. 1. Slit Lamp Examination of the eye, showing corneal deposits (CD) of cystine. PL: pupil.

Infantile nephropathic cystinosis is an autosomal recessively inherited cystine storage disorder characterized by intra-lysosomal accumulation of cystine(l). It is an important cause of inherited Fanconi syndrome(2) presenting with failure to thrive, poor feeding, rickets, photophobia, polyuria and polydipsia between 6 to 12 months of age. The condition progresses to end stage renal disease between 5-10 years of age(3). The youngest patients previously reported with cystinosis showed ESRD at 30 months(4) and CRF at 18 months(5). Our patient developed chronic renal failure at 9 months of age. The diagnosis was confirmed by slit lamp examination, which showed characteristic cystine crystals. We suggest that the diagnosis of cystinosis should be considered in young children with chronic renal failure, as outcome of treatment with cysteamine is satisfactory if started early(5).

P. Anil Kumar¶,
G. Subramanyam*,
¶Department of Pediatrics,
St. John’s Medical College Hospital,
Bangalore 560 034, India.
*Consultant Pediatrician, Nagpur.
Correspondence to:
P. Anil Kumar.
Children’s Kidney Care Center,
Department of Pediatrics,
St. John’s Medical College Hospital,
Bangalore 560 034, India.
E-mail: [email protected]  

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