Study of inherited metabolic disorders in Singapore - 13 years experience.
BACKGROUND
Recommended by the National Advisory Council of the Disabled, the Ministry of Health of Singapore supported a nationwide study of inherited metabolic disorders (IMDs). When the 5-year project ended, investigations were provided as a diagnostic service. This paper documents our 13-year experience.


METHODS
Patients with symptoms suggestive of an IMD were referred. Investigations on heparinised blood and/or urine included amino acid analysis using a Beckman 6300 Amino Acid Analyser, organic acids analysis using a Hewlett- Packard gas chromatography and mass spectrometry, mucopolysaccharides quantitative assay and high-resolution electrophoresis, sugars by thin-layer chromatography.


RESULTS
Of the 3656 patients studied from 1992 to 2005, IMDs were found in 127 (77 males; 50 females; age range, 1 day to 56 years). Their ethnic distribution was: 55.1% Chinese, 19.7% Malays, 11.0% Indians, 11.0% other races and 3.2% unknown. IMD diagnosed comprised 41 (32.3%) organic acidurias, 34 (26.8%) amino acidaemias/acidurias, 14 (11.0%) urea cycle defects, 15 (11.8%) mucopolysaccharidoses, 6 (4.7%) carbohydrate disorders and 17 (13.4%) others. Twenty-three (18.1%) cases were diagnosed during the neonatal period and 36 (28.3%) after the age of 13.


CONCLUSIONS
Positive detection rate was 3.5% and 48 IMDs were found. Significant proportion of cases had late-onset IMDs. Early identification of IMDs permits timely management, genetic counselling and prenatal diagnosis.
Tan
It-Koon
IK
Clinical Biochemistry Laboratories, Department of Pathology, Singapore General Hospital, Singapore.
Gajra
Bani
B
Lim
Maria S F
MS
D000293:Adolescent; D000328:Adult; D000596:Amino Acids / Q000378:metabolism*; D015415:Biomarkers / Q000097:blood / Q000134:cerebrospinal fluid / Q000652:urine; D002241:Carbohydrates / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D002849:Chromatography, Gas; D005260:Female; D005500:Follow-Up Studies; D006025:Glycosaminoglycans / Q000378:metabolism*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D013058:Mass Spectrometry; D008661:Metabolism, Inborn Errors / Q000453:epidemiology* / Q000378:metabolism; D008875:Middle Aged; D015995:Prevalence; D011379:Prognosis; D012189:Retrospective Studies; D012846:Singapore / Q000453:epidemiology; D014508:Urea / Q000378:metabolism*
D000596:Amino Acids; D015415:Biomarkers; D002241:Carbohydrates; D006025:Glycosaminoglycans; D014508:Urea