
twins discordant
for early infantile autism
a pair of heterozygous twins discordant
for early infantile autism is reported and the
relevant literature reviewed.  although mani-
fest organic factors were ruled out, the twins'
physical development was different.  a spe-
cific emotional etiology was not demon-
strated.  the few available twin studies offer
findings consistent with the hypothesis that
genetic factors are relevant to the develop-
ment of childhood autism.  evidence is also
presented that impaired acquisition of lan-
guage may have hereditary determinants.
a second set of probably homozygous
twins are reported who were also discordant
for autism.  this second case suggests that,
although genetic factors may play a part, in
some cases the syndrome of infantile autism
appears to be a reversible one.  in view of
this set of twins and of kanner's sibling data,
the role of genetic factors remains obscure,
and more twin studies properly documented
with blood typing are needed.
