MULTIPLE CARBOXYLASE DEFICIENCY
BN Apte, VN Tibrewala
Department of Human Genetics, Bombay Hospital Trust, 12, Marine Lines, Mumbai 400 020.
Multiple Carboxylase deficiency is an inborn error of metabolism which results from the deficiency of either biotinidase or holocarboxylase synthetase.
Both enzyme deficiencies present overlapping clinical manifestations. However, the biotinidase deficiency results in total alopecia and ataxia. Both diseases present a picture of severe organic acidaemia.
We present here a case of biotinidase deficiency. The patient is being managed for the past twelve years.
Multiple carboxylase deficiency is an inborn error of metabolism which results from the deficiency of either biotinidase or holocarboxylase synthetase. An apocarboxylase is enzymatically inactive. It gains enzymic activity only when covalently combined with biotin (Vitamin H). The function is carried out by the enzyme Holocarboxylase Synthetase.  Once the function of a given holocarboxylase is over, the coenzyme molecule, biotin, is elevated by the enzyme, biotinidase.  Deficiency of either of these enzymes results in the disease. The role of these two enzymes in the catalysis of carboxylases is shown in Fig. 1.
Deficiency of holocarboxylase synthetase in a patient results in erythematous, scaly eruptions, often periorificial, with or without moniliasis, along with the typical picture of organic acidaemia, including overwhelming episodes of acute illness in infancy with vomiting, ketosis, acidosis and dehydration progressive to coma, neutropenia or pancytopenia, lactic acidaemia propionic acidaemia together with the elevated levels of several other organic acids are also manifested. 
Deficiency of biotinidase results in ataxia, muscular hypotonia, seizures, alopecia, periorificial cutaneous eruptions, episodic metabolic acidosis, lactic acidaemia, propionic acidaemia with excessive excretion of several other organic acids.4 Biotinidase deficiency usually presents in infants as early as three months of age or even later than four years of age. We present here a case of biotinidase deficiency in a patient who is being followed by us for the past twelve years.
Five month old S.S. was the 5th child of a consanguineous marriage. Three siblings of the patient had died in early infancy. S.S. was a full term baby with no history of birth asphyxia. At 5 months of age S.S. developed tonic-clonic type of convulsions, about 6-7 per day, with up rolling of eye balls and with frothing at mouth. Prior to admission to our hospital the child was in a comatose condition for two days.
The hypotonic child had no obvious neurological deficits. Fundoscopy revealed pale optic disc. EEG showed generabilateral abnormalities. Pyruvate was 2.5 (normal range 0.2 - 2.0 mg%) and lactate was 1.8 (normal range 0.3 - 1.4 mM). Thin layer chromatographic analysis of urine showed excessive excretion of organic acids.
Elevation in the level of several organic acids together with pyruvate and lactate led us to suspect the deficiency of multiple carboxylases. The child was, therefore, put on 5 mg BD of biotin together with 25 mg BD of vitamin B1. The child showed a remarkable recovery and was discharged after three days.
Fig 1 : Shows the role of holocarboxylase and biotinidase in the catalytic conversion os apocarboxylase to holocarboxylase back
At six years of age S.S. was readmitted with total alopecia, excessive drooling, inability to walk, talk or communicate. S.S. was a normal boy just four months before he was brought again to us in this condition. (Figs. 2 and 3). He had 2-3 tremors per day and had developed large erythematous patches on the waist.
Fig 2 Fig 3 Fig 4 Fig 5 Fig 2-5 : Illustrate the complete reversal of the cutaneous lesions and the alopecia after treatment with biotin in our patient
Patientís history showed that the family had stopped giving biotin and b1 to S.S. for a period of about six months prior to this condition. Biotin and B1 were restarted. The patient again showed remarkable improvement. After two months of treatment (Biotin 10 mg BD and B1 50 mg BD), all the erythematous patches had disappeared. S.S. had developed good hair growth on scalp and eyebrows (Fig. 4). After six months of treatment S.S. had attained normality and had resumed his activities (Fig. 5). He has developed partial deafness presumably due to the damage to the auditory nerve caused during the stoppage of the treatment.
We have now established quantitative estimation of biotinidase enzyme. Quantitative estimation of biotinidase was performed in plasma of the patient and his parents. [5,6] Table 1 clearly shows that our patient has no active biotinidase whereas his father and mother being carriers show carrier range of biotinidase activity.
The child has been now on 10 mg BD of biotin, B1 has been withdrawn. S.S. is now twelve years old, well built 138 cms inheight with a normal body weight. All of his other anthropometric measurements are well within normal limits. His diet intake is good. S.S. is now in 5th standard and has been doing well in school as well as in games.
Biotinidase deficiency is transmitted as an autosomal recessive trait. Siblings of involved parents have been observed and consanguinity has been documented.  ,  Parents of S.S. have about 50% of the normal activity, which is consistent with their heterozygosity.  measurement of biotinidase activity can be performed in amniocytes which makes prenatal diagnosis possible.
Patients are effectively treated with relatively low doses of biotin. The dose most commonly employed is 10 mg of biotin twice a day.  Organic acidaemia and virtually all the clinical manifestations of the disease disappear promptly soon after the initiation of treatment. However, auditory and optic nerve losses are not recovered. [11-14] Presymptomatic treatment in a patient diagnosed by the assay of cord blood, because of the family history, has been followed by completely normal development, including vision and hearing. 
We are thankful to Miss. Meena Desai and Miss. Rekha Fulsunge for their excellent technical assistance and to Miss. Maria Gracious for preparing this manuscript.
We are thankful to Medical Director for allowing us to publish this paper.
1.Burri BJ, Sweetman L, Nyhan WL. Mutant holocarboxylase synthetase : Evidence for the enzyme defect in early infantile biotinresponsive multiple carboxylase deficiency. J Clin Invest 1981; 68 : 1491-5.
2.Thoma RW, Peterson WH. The enzymatic degradation of soluble bound biotin. J Biol Chem 1954; 210 : 569-79.
3.Nyhan WL. Multiple carboxylase deficiency. 3-Methylcrotonyl-glycinuria. In Nyhan WL : Abnormalities in amino acid metabolism in clinical. Norwalk, conn. Appleton-Century-Crofts 1984; 65-78.
4.Wolf B, Grier RE, Parker WD, Goodman SI, Allen RJ. Deficient biotinidase activity in late-onset multiple carboxylase deficiency.N Engl J Med 1983; 308 : 161.
5.Wolf B, Grier RE, Allen RJ, Goodman SI, Kien CL. Biotinidase deficiency : the enzymatic defect in late-onset multiple carboxylase deficiency. Clin Chim Acta 1983; 131 : 273-81.
6.Heard GS, Wolf B, Jefferson LG, et al. Neonatal screening for biotinidase deficiency : Results of a 1-year pilot study. 1986; 108 : 40-45.
7.Munnich A, Saudubray JM, Ogier H, Coude FX, Marsac C, Roccichiolli F, Labarthe JC, Cazenave C, Langier J, Charpentier C, Frezal J. Deficit multiple des carboxylases. Une maladie metabolique vitamino-dependate curable par la biotini. Arch Fr Pediatr 1981; 38 : 83.
8.Keeton BR, Moosa A. Organic aciduria. Treatable cause of floppy infant syndrome. Arch Dis Child 1981; 51 : 636.
9.Wolf B, Grier RE, Allen RJ, Goodman SI, Kien CL. Biotinidase deficiency : The enzymatic defect in late-onset multiple carboxylase deficiency. Clin Chim Acta 1983; 131 : 273.
10.Barlett K, Ng H, Leonard JV. A combined defect of three mitochondrial carboxylases presenting as biotin-responsive 3-methylcrotonyl glycinuria and 3-hydroxyiso- valeric aciduria. Clin Chim Acta 1980; 100 : 183.
11.Thoene J, Baker H, Yoshino M, Sweetman L. Biotin-responsive carboxylase deficiency associated with subnormal plasma and urinary biotin. N Engl J Med 1981; 304 : 817.
12.Cowan MJ, Wara DW, Packman S, Ammann AJ, Yoshino M, Sweetman L, Nyhan WL. Multiple biotin-dependent carboxylase deficiencies associated with defects in T-cell and B-cell immunity. Lancet 1979; 2 : 115.
13.Wolf B, Grier RE, Heard GS. Hearing loss in biotinidase deficiency. Lancet 1983; 2 : 1365.
14.Munnich A, Saudubray JM, Cotisson A, Coude FX, Ogier H, Charpentier C, Marsac C, Carre G, Bourgeay-Causse M, Frezal J. Biotin dependent multiple carboxylase deficiency presenting as a congential lactic acidosis. Eur J Pediatr 1981; 137 : 203.