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Dicarboxylic aciduria: A possible defect in fatty acid metabolism
ABSTRACTS OF ANNUAL MEETING 1978
325
METABOLISM
PORPHYRIA: A COMMON METABOLIC DISORDER P. M. CARTER, K. SANDY, D. BLAKE & 1. S. RATNAIKE The Royal Melbourne Hospital, Melbourne Porphyrias represent a series of disorders due to specific enzyme abnormalities in haem synthesis. The abnormal porphyrin excretion patterns consequent upon these enzyme deficiencies can aid clinical diagnosis and patient management. The incidence and typcs of abnormal porphyrin excretion detected in our routine laboratory over an 18 mth period are presented. Patients (220) with suspected porphyria and relatives (30) were investigated. Abnormal porphyrin excretion was found in 52 patients and 7 relatives. Classification of these subjects according to clinical and biochemical data was as follows:
Number of patients
Diagnosis Porphyria cutanea tarda Porphyria variegata Hereditary coproporphyria Erythropoietic protoporphyria Uncertain
29 5
Total
52
I
2 15
Number of relatives
6 I
7
The commonest presenting feature was photosensitivity. No cases were associated with acute abdominal pain and only one patient presented with acute neurological disturbance. DICARBOXYLlC ACIDURIA: A POSSIBLE DEFECT IN FATTY ACID METABOLISM R. 1. W. TRuscoTT, B. HALPERN University of Wo/longong, N.S. W. B. O/iver Latham Laboratory, Sydney M. SlUNK, H. GRIFFITHS, H. KILHAM Royal Alexandra Hospital, Sydney and F. GRUNSEIT Prince of Wales Children's Hospital, Sydney
C. 1.
PuLUN,
WILCKEN
Investigations will be described on 3 unrelated males aged 6-14 mth who presented in a semi-comatose state with a history of 2-4 days vomiting and diarrhoea. The children were characterized by an easily correctable hypoglycaemia, mild metabolic acidosis and gross hepatomegaly with normal serum transaminases and amino acids. GC/MS of urinary acid extracts revealed large amounts of adipic, suberic and sebacic acids together with suberyl glycine. Only small amounts of lactic and f3-hydroxybutyric acid were present. The above diagnostic GC pattern was not present when the children were well but could be provoked by fasting. A genetic defect is suggested by the infantile death of 2 siblings of one patient following a similar pattern of illness. We suggest that these patients may have a defect in short chain acyl CoA decarboxylase which when fat is the major energy source, leads to increased w-oxidation of fatty acids and a consequent excretion of dicarboxylic acids. SCREENING FOR NEONATAL HYPOTHYROIDISM IN SOUTH AUSTRALIA
A.
C. WILKINS,
E. F.
ROBERTSON
Children's Hospital, Adelaide
& A. C. POLLARD
Department of Chemical Pathology, Adelaide
Neonatal hypothyroidism is difficult to detect by clinical examination of the newborn baby. Undetected, it usually results in mental and physical retardation. The earlier the diagnosis is made, and treatment instituted, the better the outlook for normal development. Screening for low thyroxine levels was carried out using a modified Larsen radioimmunoassay method on a 3 mm disc of chromatography paper on which blood samples had been collected by heel stab at 5 days of age. This programme was commenced in February 1977. By April 1977, a T.S.H. method (Phadebas kit) was introduced using an 8 mm blood spot. The samples selected for T.S.H. measurement were those in the lowest 10th percentile of each thyroxine screen batch. The incorporation of the T .S.H. screen greatly reduced the number of patients recalled from 1% to I in 2500. By August 1978, approximately 30,000 newborns had been screened. In this sample, 5 cases of primary neonatal hypothyroidism and 3 cases of thyroxine binding globulin deficiency had been detected.
325
METABOLISM
PORPHYRIA: A COMMON METABOLIC DISORDER P. M. CARTER, K. SANDY, D. BLAKE & 1. S. RATNAIKE The Royal Melbourne Hospital, Melbourne Porphyrias represent a series of disorders due to specific enzyme abnormalities in haem synthesis. The abnormal porphyrin excretion patterns consequent upon these enzyme deficiencies can aid clinical diagnosis and patient management. The incidence and typcs of abnormal porphyrin excretion detected in our routine laboratory over an 18 mth period are presented. Patients (220) with suspected porphyria and relatives (30) were investigated. Abnormal porphyrin excretion was found in 52 patients and 7 relatives. Classification of these subjects according to clinical and biochemical data was as follows:
Number of patients
Diagnosis Porphyria cutanea tarda Porphyria variegata Hereditary coproporphyria Erythropoietic protoporphyria Uncertain
29 5
Total
52
I
2 15
Number of relatives
6 I
7
The commonest presenting feature was photosensitivity. No cases were associated with acute abdominal pain and only one patient presented with acute neurological disturbance. DICARBOXYLlC ACIDURIA: A POSSIBLE DEFECT IN FATTY ACID METABOLISM R. 1. W. TRuscoTT, B. HALPERN University of Wo/longong, N.S. W. B. O/iver Latham Laboratory, Sydney M. SlUNK, H. GRIFFITHS, H. KILHAM Royal Alexandra Hospital, Sydney and F. GRUNSEIT Prince of Wales Children's Hospital, Sydney
C. 1.
PuLUN,
WILCKEN
Investigations will be described on 3 unrelated males aged 6-14 mth who presented in a semi-comatose state with a history of 2-4 days vomiting and diarrhoea. The children were characterized by an easily correctable hypoglycaemia, mild metabolic acidosis and gross hepatomegaly with normal serum transaminases and amino acids. GC/MS of urinary acid extracts revealed large amounts of adipic, suberic and sebacic acids together with suberyl glycine. Only small amounts of lactic and f3-hydroxybutyric acid were present. The above diagnostic GC pattern was not present when the children were well but could be provoked by fasting. A genetic defect is suggested by the infantile death of 2 siblings of one patient following a similar pattern of illness. We suggest that these patients may have a defect in short chain acyl CoA decarboxylase which when fat is the major energy source, leads to increased w-oxidation of fatty acids and a consequent excretion of dicarboxylic acids. SCREENING FOR NEONATAL HYPOTHYROIDISM IN SOUTH AUSTRALIA
A.
C. WILKINS,
E. F.
ROBERTSON
Children's Hospital, Adelaide
& A. C. POLLARD
Department of Chemical Pathology, Adelaide
Neonatal hypothyroidism is difficult to detect by clinical examination of the newborn baby. Undetected, it usually results in mental and physical retardation. The earlier the diagnosis is made, and treatment instituted, the better the outlook for normal development. Screening for low thyroxine levels was carried out using a modified Larsen radioimmunoassay method on a 3 mm disc of chromatography paper on which blood samples had been collected by heel stab at 5 days of age. This programme was commenced in February 1977. By April 1977, a T.S.H. method (Phadebas kit) was introduced using an 8 mm blood spot. The samples selected for T.S.H. measurement were those in the lowest 10th percentile of each thyroxine screen batch. The incorporation of the T .S.H. screen greatly reduced the number of patients recalled from 1% to I in 2500. By August 1978, approximately 30,000 newborns had been screened. In this sample, 5 cases of primary neonatal hypothyroidism and 3 cases of thyroxine binding globulin deficiency had been detected.