37
children born to an exposed parent or parents
have shown, on the basis of incidence of gross
may take several generationsto affect the pheno-
type, recognition of their radiation etiology may
be extremely difficult. Neel et al. are at present
anomalies, no evidence of inherited radiation-
carrying out more sophisticated studies in the Jap-
induced mutations.
The principal aberrations noted in Marshailese
anese, concerned with the occurrenceof variant
forms of 24 serum proteins and erythrocyte en-
adults and children have been bilateral shortening
of the fifth finger, prominent headof ulna, dislocated wrist, enlarged cornea, tortuosity of retinal
vessels, asymmetry of face, congenital nystagmus,
and pigmentation of the cornea. Studies of familial
patterns of such defects have not been done; they
are not related to exposure.
The possible increase in miscarriages andstillbirths among the exposed women duringthefirst
zymes. He and Dr. R.E. Ferrell kindly consented
to examine blood samples collected in 1974 from
187 Marshallese children and parents (exposed
and unexposed). The results, summarized below,
included nosignificant findings indicating radiadon-induced mutations.
b. The Frequency of ‘“‘Rare”’ Protein Variants.
duced lethal mutations in germ cells of the ovary
The blood samples mentioned above were subjected to electrophoretic analyses for polymorphisms and rare variants of proteins and erythro-
chromosome aberrationsin peripheral blood lym-
Neel et al.82 as follows.
5 years may lead to speculations that radiationin-
or, less likely, in sperm cells.* The presence of
phocytes in the Marshallese 10 years post exposure, and the possible somatic mutation in the
hemoglobin, described above, support speculations
that mutations in the germ plasm occurred and
might be detected in the offspring by moresensitive tests. However, in view of the relatively small
dose of radiation and the small size of the populaton, on 4 prior: grounds a clear-cut demonstration
of a genetic effect of radiation in the children born
to exposed parents would seem unlikely. Nevertheless, given the nature of the circumstances,it
cyte enzymes.82 The findings were summarized by
‘Blood specimens from a sample of 187 Marshall Islanders were studied with reference to variants of 24 serum proteins and erythrocyte enzymes.
Six of the traits studied exhibited genetic polymorphisms (adenosine deaminase, phosphoglucomutase;, acid phosphatase, 6-phosphogluconate
dehydrogenase, haptoglobin, group specific component). There was in addition one‘rare’ variant
(of albumin) in 4047 determinations. Theseresuits
on rare variants have been combined with those of
others on Micronesians, and the frequency ofrare
collect such data. Since recessive combinations
variants in Micronesians compared withthefrequencies in West European Caucasians, Japanese,
*About one-half the miscarriages occurred in exposed women
miasried to unexposed men.
such comparisons, and, although the observed values for the four ethnic groups differ by a factor of
has been deemed desirable to make every effort to
and Amerindians. There are manydifficulties in
Table 22
Gene Frequencies for Six Genetic Polymorphisms in the Marshall Isiands®?
Phenotype
System
Adenosine deaminase
Groupspecific component
Haptogiobin*
Phosphogiucomutase,**
Acid phosphatase
6-Phosphogiuconate dehydrogenase
1
2-1
2
Total
167
116
56
156
18
50 ©
93
26
0
2
32
1
185
168
177
184
ADA!
Gel
Hp?
PGM,'
=
=
=
=
185
APA
= 0.743
A
AB
B
164
21
0
101
*The Hp® type was observed in 4 individuals.
73
11
185
Genefrequency
0.951
0.839
0.579
0.912
6-PGDA = 0,943
**Two examples of the PGM phenotype 2-7 and a single phenotype |-7 were observed (PGM,7 = 0.008).