Early diagnosis of co-existent ß-thalassemia and alkaptonuria
Our case was a 1-year 5-month-old male child, brought with complaints of reddish discoloration of the nappies and clothes and breath-holding spells. There was no abnormal odor of the skin or urine. There was no history of crying while passing urine, poor urinary stream or bleeding from skin or mucus membrane. There was no history of fever, rash, abdominal pain, constipation or alteration of sensorium. The mother of the baby was a known case of thalassemia trait; however, had never received transfusion. The baby’s parents were consanguineous cousins. The father’s thalassemia status could not be elicited.\nOn examination, the baby weighed 8.5 kg with head circumference 44 cm and length 81 cm and the baby was conscious and alert. There was no jaundice or dehydration or abnormal odor. Arterial oxygen saturation (SpO2) was 94%. The capillary refill time was between 3 s and 4 s. The heart rate was 146/min. The respiratory rate was 26/min. Non-invasive blood pressure was 73/44 (54) mm Hg. Respiratory system examination revealed normal chest movements with equal air entry on both sides. Abdomen was soft. The liver was palpable 1 cm below the costal margin. The spleen was not felt. There were no other masses felt. Examination of the cardiovascular system showed normal heart sounds. There were no added heart sounds, murmurs or rubs. Reflexes were normal, and he had hypotonia. There was no neck stiffness. The spine and gait were normal. The eyes, musculoskeletal system, skin, and cardiovascular systems were normal.\nThe baby was admitted for observation and investigations, and the initial differential diagnosis included alkaptonuria, myoglobinuria, hemoglobinuria, porphyria, and hemochromatosis. He had an under-current viral illness, which was managed symptomatically. The urine routine examination and ultrasound abdomen were normal.\nThe hemoglobin levels were low with microcytic hypochromic anemia. Hemoglobin was 10.2 g/dl (normal 10.5-14 g/dl), packed cell volume, mean corpuscular volume (MCV) and mean corpuscular hemoglobin were low at 31.9% (normal 32-42%), 68 fl (normal 72-88 fl), and 21.8 pg (normal 24-30 pg), respectively. MCV concentration was 32% (normal 31.5-34.5%) and red cell distribution width 17.1% (normal 11-16%). Serum iron, total iron binding capacity, and ferritin levels were within the reference range. Hemoglobin analysis by cation exchange high-pressure liquid chromatography (HPLC) revealed Hb A0 to be 80.4% and Hb A2 to be 6.1% (normal 2.40-3.60). The HPLC picture on correlation with the complete hemogram suggested β-thalassemia trait. DNA studies confirmed the beta globin gene defect of β-thalassemia.\nThe serum electrolytes and serum bicarbonate were normal. The renal function and liver function were within the reference range. The child’s urine porphyrin, estimations were within normal levels, and serum lead levels and δ-amino levulinic acid were not tested. Myoglobin and hemoglobin levels were undetected in urine. No abnormalities were detected on the electroencephalogram, leading us to believe that the breath holding spells were due to anemia.\nUrine was of normal color when voided but turned black over variable periods spontaneously; furthermore, turned black with Benedict’s reagent, strong alkali (filter paper impregnated with 10% sodium hydroxide turned black within 5 min when dipped into the urine) and ferric chloride (addition of dilute ferric chloride solution drop by drop showed an evanescent violet blue color). The urine of an alkaptonuric individual usually appears normal when passed. However, it starts to darken upon standing, and this is caused by oxidation and polymerization of the homogentisic acid, and it is enhanced with an alkaline pH.\nBenedict’s test was strongly positive with red brown precipitate at the bottom and black colored supernatant. Glucose oxidase test (with multistix) was negative excluding the role of glucose as reducing substance. For the qualitative assay of HA, to 0.5 ml of sample, a few drops of 10% ammonia was added followed by the addition of 3% silver nitrate solution. A greenish black color developed, signifying the presence of a substantial amount of HA. Quantitative examination of urine by tandem mass spectrometry revealed that concentration of HA in urine was 91 mg/dl (normally HA is not present in urine). Parents’ urine was negative for HA. Due to the financial constraints, confirmatory diagnosis by DNA mutation analysis could not be carried out.\nThe child was treated symptomatically, and he was given vitamin C (50 mg once a day for 3 months), low phenylalanine and tyrosine diet, and advised to monitor counts, get liver and renal function tests carried out every 2 weeks. On the request of his parents, the child was discharged after 3 days and advised to follow-up in the outpatient department (OPD). After 3 months post-therapy, his HA levels had not reduced. Currently, the baby is under follow-up every 6 months in the OPD.