502 



It seems that a considerable number of the alkaptonuric individuals 

 are the children of iirst cousin marriages (Garrod). That does not 

 mean that marriage of first cousins tends to alkaptonuria, but the pres- 

 ence of a recessive characteristic in both of the parents will, of course, 

 intensify the production of the recessive characteristic in the offspring. 

 The following table shows that in eight consanguineous marriages there 

 were fifteen alkaptonuric individuals, whereas in ten families where the 

 parents were not blood relations there were only nineteen alkaptonuric 

 members : 



Families the Offsprings of First Cousins 



Number of 



Names of Alkaptonuric 



Observers Members 



Pavy 4 



R. Kirk 3 



Garrod 2 



Erich Meyer 1 



Ogden 1 



Hammarsten 2 



Grutterink and van der Bergh .... 1 

 Cronvall . 1 



1. 

 2. 

 3. 

 4. 

 5. 

 ti. 

 7. 



Families of Parents Who Were Not Blood 

 Relations 



Number of 



Names of Alkaptonuric 



Observers Members 



W. Smith and Garrod 2 



Ewald Stier 1 



Nocciola and Domenici 1 



Marshall and Futcher 3 



Langstein and E. Meyer 1 



Garrod and T. W. Clarke 1 



Grutterink and van der Bergh ... 2 

 Grutterink and van der Bergh ... 4 



Schumm 1 



Fromherz . , 



Number of families, 8 15 Number of families, 10 19 ' 



1 In some instances private information has supplemented the published records. 

 (Garrod.) 



Debenedetti has recently described a family where no instances of alkaptonuria 

 were known until two cousins married. Four sons of this marriage all had alkapton- 

 uria. The two daughters escaped. 



