[Jacob-list] Tay-Sachs in Jacob sheep - more carriers

[Jacobflock at aol.com]

Dear listers:
 
Some may recall my earlier post on Tay-Sachs in Jacobs and some may have  
read the article in the ALBC newsletter.  At the time, the source ram at  the 
top of the pyramid was Turner 183K.  Within the past six weeks another  
flock has turned up with carriers which come through the Lasseau and Fieldwood  
lines.  Not all sheep in these lines are carriers of course and these lines 
 should be conserved.  Don't panic. Don't send your sheep to the  knacker 
because a few carriers came from through these lines.  We kept  probable 
carriers, based on pedigree records, for ten years waiting for a test  and 
diagnosis.  Now we know the real background of each sheep and which are  clear, 
which are carriers.  Each group is on a separate breeding  program.
 
Please clearly understand that this is a simple recessive mutated gene and  
the presentation of affected lambs which would die at about six months is 
rather  low unless one's flock has a lot of breeding ewe carriers.. and a 
carrier ram.  The mutant gene codes for hexosominidase A (hex A) and the 
decoding of the  entire sequence of this gene showed that it was 86% identical to 
the human hex A  gene and in Jacobs, is only one nucleotide base different 
than a  non-carrier, normal sheep. 
 
Who might look for the mutant gene?  Breeders, perhaps somewhat  limited by 
geography, who are along the East coast may have a higher probability  of 
carriers with sheep from these lines but this is not a limitation. There have 
 been pedigree errors .. some precede the JSBA and JSC records.
 
This latest finding of carriers involved several ewes and a ram lamb.   The 
breeder siad that they could not recall having an affected lamb over the 
six  years they have had their flock.  I would encourage breeders who have  
Jacobs out of these lines to take advantage of the free test materials, it can 
 be done by cheek swab or lancet (vs. blood draw in a purple top tube), the 
 test for the mutant gene takes about ten days and is free, and you can 
remain  anonymous.  Please contact _Edwin.Kolodny at nyumc.org_ 
(mailto:Edwin.Kolodny at nyumc.org)  if you want to  support the breed and possibly help a child 
and his/her family ... better yet,  reverse the reasons for contacting Dr. 
Kolodny.   
 
There may be more on this in an upcoming ALBC newsletter.   

Fred Horak
St. Jude's Farm
1165 E. Lucas Rd.
Lucas, TX   75002-7455
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