Section 15 — Human Genetics 



exception of the galactosemic child — as well as 

 the parents were heterozygous carriers. 



The biochemical as well as the cytological 

 results of this investigation of linkage relations 

 will be discussed. 



sary, but this is true also of diabetics who re- 

 quire insulin. 



While the "U" series of drugs do not constitute 

 a cure for mongolism, they do allow mongoloids 

 to lead a more normal life and point the way to a 

 genetic solution of the problem. 



15.62. Down's Syndrome: A Genetic Abnormality 

 Improved by Medication. Henry Turkel 

 (Detroit, U.S.A). 



In 1866, both Gregor J. Mendel brought out 

 his theory of heredity and Dr. Langdon Down 

 coined the name, mongoloid, for a particular 

 group of patients, it was not until 1958 that Dr. 

 Jerome LeJeune pointed out their relationship in 

 discovering the Trisomy 21. 



And in 196J Dr. LeJeune said: "Cytogenics 

 must not be restricted to genetic counseling. 

 Even more important than the mapping of 

 various traits would be the establishment of 

 solid relationship between cytogenics and bio- 

 chemistry, leading to the possibility of chemical 

 correction of inborn errors." 



Though various abnormal chemicals have 

 been found in mongoloids, none have been 

 pinpointed as the real cause of the various in- 

 born structural and functional anomalies 

 characteristic of mongoloids. 



Mongolism appears to be a complexity of 

 problems, but it is like phenylketonuria, galac- 

 tosemia, diabetes, etc., in that it is a part of the 

 group of conditions which are inborn. In the 

 case of, for example, phenylketonuria, the 

 mother is capable of protecting the fetus, and the 

 fetus does not begin abnormal development 

 until after birth. However, in the case of the 

 mongoloid, the mother is incapable of protecting 

 the fetus, thus, the mongoloidal fetus is born 

 with a group of abnormalities which have al- 

 ready passed into secondary and tertiary stages, 

 thus, piling abnormalities upon abnormalities. 



The treatment for the improvement of the 

 mongoloid is based upon assisting the mongo- 

 loid to build through normal means a more 

 normal manner of growth, removing the se- 

 condary and tertiary outgrowths of the original 

 inborn anomalies. This should enable the genetist 

 to pinpoint the inborn anomalies more easily 

 with the hope that future findings will dictate a 

 correction. 



Though the use of the "U" series of drugs 

 does not enable the physician to change the 

 chromosomal pattern, he can still alter the resul- 

 tant abnormalities and bring the mongoloid 

 into the sphere of normal society. Life-long 

 medication of maintenance doses may be neces- 



15.63. Serum Phenylalanine Levels in the Newborn. 



David Yi-Yung Hsia, J. D. Berman and 

 H. M. Slatis (Chicago, U.S.A.). 



Phenylketonuria is a hereditary metabolic 

 disease caused by a deficiency of the enzyme 

 phenylalanine hydroxylase. The mental retarda- 

 tion in this condition can be effectively prevented 

 if treatment with a diet low in phenylalanine 

 content is started very early in infancy. Two 

 approaches have been proposed for routine 

 screening of newborns for phenylketonuria: (1) 

 testing of urine for phenylpyruvic acid and (2) 

 determining phenylalanine levels in the serum. 

 The first has the disadvantage of not being 

 reliable until 4-6 weeks of age. Methods for the 

 second have until now only been semi-quantita- 

 tive based upon the inhibition of Bacillus subtillis 

 by beta-2-thienyalanine in a minimum culture 

 medium. 



The present paper will describe a survey of 

 serum phenylalanine levels in 4000 newborn 

 infants. In each instance, 0.1 ml of capillary 

 blood was obtained from a single heel puncture 

 and the serum phenylalanine level determined by 

 the fiuorimetric method of McCaman and 

 Robins( 1 ). The data will be analyzed in terms 

 of sex, age, race, parity, maternal age, and 

 birthweight, and compared with observations on 

 known phenylketonuric infants followed in our 

 own Clinic and from other centers. 



Since one laboratory technician can perform 

 up to 100 determinations of serum phenylalanine 

 daily, this approach using a quantitative method 

 should serve as the best means of screening for 

 phenylketonuria during the newborn period. 



1. /. Lab. & Clin. Med. 59, 885, 1962. 



15.64. Detection of Carrier State for Phenylketonuria 

 in Familial Genetic Inquiries. J. Dodinval- 

 Versie, P. Dodinval, R. Malchair and P. 

 Moureau (Liege, Belgium). 



For a few years, it has been possible to 



290 



