A basic investigation for inherited metabolic diseases: indication for genomic approach

Abstract

The inherited metabolic diseases (IMDs) or Inborn errors of metabolism (IEM) are mostly determined by single abnormal autosomal recessive genes; which though rare as a group account for a sizeable proportion of disorders in very large populations. There is neither a screening policy as in many advanced countries nor have the diseases been investigated in the concomitant institution for the handicapped in Nigeria.
Sixty-one (61) subjects (40M, 20F); Mean age 18.38 + 1.3 (SD) years who were residents of the Oluyole Cheshire School and the School for the Handicapped both in the Eleyele area of Ibadan, were selected for the study. Thirty-five (35) apparently healthy (no manifest genetic disorder) individuals, mean age 19.00 + 1.30 (SD) years were selected as controls. The mean weight of the handicapped was 40.9 + 1.1kg while the controls was 47.63 + 1.17 (SD) kg. Mid morning urine samples were collected from all subjects and controls. Aversion for venepuncture by both subjects and their care providers prevented some blood assays. All subjects were subjected to Benedicts reaction, the Ferric Chloride (FeC13) test, clinstix, and the ninhydrin reactions.
Thirty-two (32) out of a population of 45 (71.1%) at the Oluyole Chesire Home and 29 out of a population 42 (69.1%) at the School for the handicapped participated in the study. The handicapped subjects had significantly lower weight than controls (P<0.01). There was evidence of marked neurological dysfunction in most of the residents. The FeC13 test and the ninhydrin reactions were negative in both the handicapped and controls subjects. In Benedict\'s reaction 37 (60.7%) of the handicapped subjects gave a negative reaction while 24 (68, 57%) of the controls gave a negative reaction. Clinstix test gave identical reaction as for Benedict\'s reaction. Twenty-four (24) (39.3%) of the handicapped subjects gave trace positive reaction with Benedict\'s reaction while 11 (31.43%) of the controls gave trace positive reaction with clinistix.
This basic investigation may not exclude the IMDs (or IEMs) such as phenylketonuria (PKU) histidinaemia, Mapple syrup urine disease (MSUD), galactosaemia, Lesch-nyhan syndrome and many others but an indication for more sensitive methods such as technics of genomics and a national reference center equipped with such facilities. The recent completion of the Human Genome project makes this an urgent need. Autosomal Inherited Metabolic diseases, recessive genes, neurological dysfunction, genomics, Human Genome Project, screening policy, handicapped subjects


Journal of Biomedical Investigation Vol. 4 (1) 2006: pp. 23-27