Dr. Bruce and Professor Dana Klein 's Teaching Blogs: October 2012

I met a lady at a prayer meeting today who was from Louisiana. I grew up in St.Mary Parish as my dad worked for the Cargil Company there. So it is dear to me. This lady is Apostolic and began to relate to
me that she had lost several children to Tay Sachs disease. I know a great deal about this disorder as I actually have cared for children affected by the disorder in my Nursing Career doing private home duty.
When she began to give me the names of her family I was floored. None of the names were Acadian.
They were names of Jewish parentage that had intermarried among the Acadians. I have included an article that speaks of one of the genetic works and Tay Sachs and its connections.

Letters to the Editor 781
We hope that Palomaki et al.'s letter and our reply
will further encourage those involved in Down syndrome
screening to question all aspects of the procedures
that they are following.
JANINE C. BISHOP,* FRANK D. J. DUNSTAN,*
BARRY J. NIx,* TIMOTHY M. REYNOLDSt
AND ALLAN SWIFTS
*School of Mathematics, University of Wales, Cardiff;
tDepartment of Chemical Pathology, Royal Gwent
Hospital, Newport; and *EURO/DPC Limited,
Witney, Oxfordshire, United Kingdom
References
Macri JN, Kasturi RV, Krantz DA, Cook EJ, Larsen JW
(1990) Maternal serum alpha-fetoprotein (MSAFP) patientspecific
risk reporting: its use and misuse. AmJ Hum Genet
46:587-590
Parvin CA, Gray DL, Kessler G (1991) Influence of assay
method differences on multiple of the median distributions:
maternal serum alpha-fetoprotein as an example.
Clin Chem 37:637-642
Reynolds T, John R (1992) Comparison of assay kits for unconjugated
estriol shows that expressing results as multiples
of the median causes unacceptable variation in calculated
risk factors for Down syndrome. Clin Chem
38:1888-1893
© 1993 by The American Society of Human Genetics. All rights reserved.
0002-9297/93/5303-0025$02.00
Am.J. Hum. Genet. 53:781-782, 1993
Tay-Sachs Genes in Acadians
To the Editor:
McDowell et al. (1992) may have predated the entry of
the Tay-Sachs gene into the Acadian population of
Louisiana. They mentioned our study of inbreeding in
this population isolate (Thurmon and DeFraites 1974)
but apparently did not notice in it the exception to
their conclusions. The random inbreeding coefficient
was .0770, one of the highest ever documented in a
human isolate. It implied that, in essence, every member
of the isolate was related to every other member. We
further documented this with a computer methodology
(Thurmon et al. 1982). All founders of the isolate and
all of their descendants were identified. Though there
were great numbers, the program logic made it simple
to trace relationships. At generation IV, we found that
each person in the isolate had direct lineage to each of
the founders. This was done as part of a cancer study,
and, though submitted several times for publication, it
never survived reviewers who seemed determined not
to allow publication of any work that implied a genetic
basis of cancer.
In the course of our studies, we encountered the
Jews of Acadiana. The land that was granted to the
Acadian founders was sparse and foreboding. Even the
local Native Americans considered it an area of pestilence
and evil spirits. The only Native Americans who
actually resided there were regarded by their peers as
enchanted. For the first few generations, the Acadians
were the only Caucasians in the area, and there was no
room for anybody else. They cleared and drained the
land and turned it into a pleasant habitat and a worthwhile
market. Then the merchants began to arrive.
Among the first were a few Jewish families of Ashkenazi
derivation. The Acadians accepted them despite
their religious differences, possibly because the Acadians
had arrived in Louisiana as a result of religious
persecution. There were probably more pragmatic reasons
also. The Jews were moneyed and cultured.
Like so many other in-migrants into Acadiana, the
Jews did not maintain their culture but were themselves
acculturated. Only a few synagogues were established,
and none of the older ones survives. Many of the descendants
of the early Jewish in-migrants are unaware
of their Jewish heritage. Names of towns, communities,
and buildings are the only solid Jewish records, because
the genealogical record is only of Catholics. Jews do
not appear in it unless they married a Catholic or embraced
the religion themselves.
From our data, it would seem that any Acadian genealogy
that traced to only a single ancestral couple
would be an incomplete genealogy. Careful studies
might reveal both the actual genealogy and the Jewish
connection. It is possible, of course, that unacknowledged
paternity could account for gene flow and might
not be found in the genealogical record. However, the
very existence in the population of a well-accepted
Ashkenazi Jewish element is a much more proximate
likelihood as a source of Tay-Sachs genes than is the
ancient source posited by McDowell et al.
It is also possible that McDowell et al. were not
working with an Acadian genealogy. About the same
time that the merchants began to arrive in Acadiana,
the French Revolution produced an influx of non-Acadian
French in-migrants. Many were of aristocratic lineage,
so they held themselves aloof from the Acadians.
782 Letters to the Editor
Some of their descendants do so to this day, and,
among them, a genealogy could well trace to a single
ancestral couple. With few exceptions, their surnames
are different from those of the Acadian founders. Even
the exceptions should prove no problem to define in
careful genealogical studies.
THEODORE F. THURMON
Genetics Section
Department of Pediatrics
Louisiana State University School of Medicine,
Shreveport
References
McDowell GA, Mules EH, Fabacher P, Shapira E, Blitzer MG
(1992) The presence of two different infantile Tay-Sachs
disease mutations in a Cajun population. Am J Hum Genet
51:1071-1077
Thurmon TF, DeFraites EB (1974) Genetic studies of the
French-Acadians of Louisiana. Birth Defects 10:201-204
Thurmon TF, Macias BF, Ursin SA, Robertson KP (1982)
Founders: a microcomputer program for storage and analysis
of pedigrees of descendants of a founder group. Abstracts
of the National Birth Defects Conference. National
Birth Defects Foundation, White Plains, NY
© 1993 by The American Society of Human Genetics. All rights reserved.
0002-9297/93/5303-0026$02.00
Am. J. Hum. Genet. 53:782-783, 1993
Reply to Thurmon
To the Editor:
Dr. Thurmon points out the many pitfalls inherent in
collecting and interpreting genealogical data. We took
into account such confounding factors as nonpaternity
and undocumented relationships when analyzing our
pedigrees, and we believe that entry of the Tay-Sachs
disease (TSD) exon 11 insertion allele into the Cajun
population after the early 19th century is inconsistent
with the available genealogical data.
Dr. Thurmon's work demonstrates convincingly that
the current population of southwest Louisiana is very
closely related, and he is correct that our pedigrees are
incomplete. We purposely eliminated from our study
those lines of the families which we demonstrated by
enzyme and molecular analysis not to carry the insertion
allele. We were fortunate enough to be able to test
family members two to four generations removed from
the probands and were able to eliminate 1/2-7/8 of the
individuals from each pedigree in our study. What information
we have on the excluded branches of our
pedigrees suggests that there are indeed multiple common
ancestors among these families. However, these
other relationships are not informative as to the origin
of the insertion allele.
Not all of the relatives of the insertion carriers were
French Acadian, but most were, and all of the families
in our study consider themselves to be members of the
Cajun population. We determined French Acadian ancestry
either by surname or by the identification of ancestors
who lived in Acadia. In addition to the Acadians,
southwest Louisiana was home to a German
settlement established in 1717 and referred to as the
"German Coast." Histories of this settlement state that
Jews were among the German immigrants, but, as Dr.
Thurmon points out, there is no documentation of this
(Deiler 1909). When we began our genealogical work it
seemed likely that the origin of the insertion allele
would be among these German settlers. However, we
have found no evidence to support a "German" origin
of this allele. One of the obligate carriers in our study
does not have any German relatives in his TSD carrier
lines. As for the German relatives of the other obligate
carriers, one German couple was found to be common
only to three of the seven obligate carriers through carrier
lines. Since the TSD carrier frequency among Jews
is increased, it is possible that more than one unrelated
family carrying this allele came to southwest Louisiana,
although there is no evidence that there were many
Jewish families in this early German community. Other
genetic disorders increased in the Jewish population,
such as Gaucher disease, are not reported in the Cajun
population to suggest any large influx of Jewish alleles.
If the origin of this allele is a single Jewish founder who
is unrecognized because of a case of nonpaternity, then
a common ancestral couple, albeit the wrong ancestral
couple, still will be found. The timing of the entry of
the TSD allele would be correct, though the geographic
origin of the allele may not.
The conclusions of our study are supported by our
data even after consideration of the possible confounding
factors which Dr. Thurmon raises: namely, that (a)
our pedigrees indicate that the insertion allele has been
in southwest Louisiana at least since 1850 and probably
since the founding of the Cajun community, and (b)
founder effect is responsible, in part, for the increased
occurrence of TSD in the Cajun community.

Pray for the Healing and Salvation of those in the Acadian Communities.
In Jesus Name,
Sis.Dana Klein