Clinical conference; cystinosis.

DR. KRETCHMER: For many years pediatri cians have known a group of inherited diseases associated with specific biochemical defects. Actually, these diseases were first compiled and demonstrated by Sir Archibald Garrod ap proximately 50 years ago. The case we would like to present, one of cystinosis or cystine storage disease, is an example of one of the so called inborn errors of metabolism. Patient B.F. was admitted to the New York Hospital with a chief complaint of growth re tardation. She was the product of a normal, full-term, spontaneous delivery, and developed well until 2 years of age when growth retarda tion was noted. The child has photophobia and has always demonstrated polyunia. There has been no his tory of convulsions. The patient has been fol bowed by a private physician for the past 2 years. The members of the family are indicated in Figure 1. There were three deaths, the maternal father who died of diabetes mellitus compli cated with arteriosclerosis; and two siblings of the father, one who died of poliomyelitis and the other of pneumonia. The father and mother of the present patient are living and well, one sibling died last year at the age of 7 years of cystine storage disease, and an elder male sibling of 11 years is alive and well. The physical examination indicated a tern perature of 37.7°C, a pulse of 100, respira tions of 20, and a normal blood pressure. The patient is 92 cm tall and weighs 13.2 kg, and is a small, doll-like, pale, co-operative, bright girl. Also noted were the diminutive stature, haziness of the corneas, photophobia and polyuria. The neurobogic examination was physiologic in all respects. Laboratory examinations were as follows. Urine: Specific gravity 1.010 and pH 6.0; protein excretion, 0.7 gm/12 hr (the normal figure for this laboratory is less than 0.1 gm/ 12 hr); in a 12-hour specimen, erythrocytes 0; leukocytes 2,200,000 (normal for a female of this age), casts 50,000 (25,000 is normal in this laboratory); the child also had glycosuria and the sugar was identified as glucose. Chemical analyses of the blood: Urea-nitro gen 30 to 45 mg/100 ml; carbon dioxide 22 rnM/l; sodium 138 mEq/l; potassium 2.7 to 3.5 mEq/l; albumin 5.0 and globulin 2.5 gm/ 100 ml; cholesterol 375 mg/100 ml; creatinine 1.8 mg/100 ml (approximately twice normal); alkaline phosphatase 4.1 units (normal); cab cium 4.8 rnEq/l; and phosphorus 3.2 mEq/l. The urea clearance was 20% of normal for adults. The clearance of inulin was 12% of normal for adults and the clearance of amino nitrogen was 4 ml/min (normal clearance is 1 to 2 ml/rnin). As the gbomerular filtration rate is one-fifth of the normal, the amino-mtro gen was cleared at approximately 20 to 30 times the normal rate. Amino-nitrogen in the blood was 4 mg/100 ml (in our series the mean normal is 2.5 mg). It is interesting that in at least 12 different de terminations the concentration of amino-nitro gen in the urine ranged from 2 to 19 mg/kg! 24 hr with an average of 11 mg/kg/24 hr (normal, 2 to 4 mg/kg/24 hr).