HbVar (http://globin.bx.psu.edu/hbvar) is a locus-specific database (LSDB) 
developed in 2001 by a multi-center academic effort to provide timely 
information on the genomic sequence changes leading to hemoglobin variants and 
all types of thalassemia and hemoglobinopathies. Database records include 
extensive phenotypic descriptions, biochemical and hematological effects, 
associated pathology, and ethnic occurrence, accompanied by mutation frequencies 
and references. In addition to the regular updates to entries, we report 
significant advances and updates, which can be useful not only for HbVar users 
but also for other LSDB development and curation in general. The query page 
provides more functionality but in a simpler, more user-friendly format and 
known single nucleotide polymorphisms in the human alpha- and beta-globin loci 
are provided automatically. Population-specific beta-thalassemia mutation 
frequencies for 31 population groups have been added and/or modified and the 
previously reported delta- and alpha-thalassemia mutation frequency data from 10 
population groups have also been incorporated. In addition, an independent 
flat-file database, named XPRbase (http://www.goldenhelix.org/xprbase), has been 
developed and linked to the main HbVar web page to provide a succinct listing of 
51 experimental protocols available for globin gene mutation screening. These 
updates significantly augment the database profile and quality of information 
provided, which should increase the already high impact of the HbVar database, 
while its combination with the UCSC powerful genome browser and the ITHANET web 
portal paves the way for drawing connections of clinical importance, that is 
from genome to function to phenotype.