ASHI News
News and Information You Need To Know.

Announcement: Rare HLA alleles

Derek Middleton, David Sayer, Ann-Margaret Little, Marcelo Fernandez-Vina

Contact:  derek.middleton@belfasttrust.hscni.net

We are concerned by the growth in the number of HLA alleles, many of which are extremely rare, and the impact of these alleles on typing strategies.  Thus we would like to gather information on just how frequently these alleles occur.  Our ultimate aim is to have a record of alleles that have only been found in one individual, family or population.  We would then ask for possible consideration by the HLA Nomenclature Committee for an indication in the allele name designating that it rarely occurs.

We have prepared three spreadsheets, as follow showing whether or not HLA alleles occur in world-wide populations on the website www.allelefrequencies.net.  You can also access these spreadsheets by clicking on the following:

• HLA pop 1-3 spreadsheet
• HLA in no pops spreadsheet

1. Those alleles that do not occur in any of the populations on the website. Information on the ethnicity of individual in whom the allele was first sequenced and information on any confirmation of this sequence have been added.

2. Those alleles that occur in 1-3 populations on the website. For these alleles, the name of the population in which the allele occurs and the frequency of that allele in that population have been listed.

3. Those alleles that occur in more than three populations on the website. In this instance, the number of populations that have that allele has been listed.

In all three attachments, data from the recent ASHI report indicating how frequently alleles appear in the USA has been added.

C = common
WD = Well-documented (0.5% - 0.01%)
Column left blank = rare <0.01%)

The spreadsheets are posted on the 15th IHWS web page and we are now asking you to provide data on these alleles that occur in zero populations or in 1-3 populations. If you find any of these alleles in populations you have typed, we would like to know:

The name of the population
The ethnicity of the individual(s) carrying the allele
Source of individual—why was s/he typed
In how many unrelated individuals have you found the allele
The phenotype, or if possible the haplotype, in which the allele has been found
The method of detection
If the allele has been re-sequenced, we will encourage individuals to submit confirmation to IMGT

We ask that you contact derek.middleton@belfasttrust.hscni.net with this information in order that the spreadsheets can be up-dated. Please contact Derek even if you cannot provide all the information requested.