About Human Gene Nomenclature
Guidelines for human gene nomenclature were first published in 1979 , when the Human Gene Nomenclature Committee was first given the authority to approve and implement human gene names and symbols. Updates of these guidelines were published in 1987 ,1995, and 1997. With the recent publications of the complete human genome sequence there is an estimated total of 26,000-40,000 genes, as suggested by the International Human Genome Sequencing Consortium and Venter et al. Thus, the guidelines have been updated to accommodate their application to this wealth of information, although symbols are still only assigned when required for communication. These updates were derived with input from the HUGO Gene Nomenclature Committee (HGNC) International Advisory Committee and attendees of the ASHG01NW Gene Nomenclature Workshop. All approved human gene symbols can be found in the HGNC database.

Philosophy

The philosophy of the HGNC remains "that gene nomenclature should evolve with new technology rather than be restrictive as sometimes occurs when historical and single gene nomenclature systems are applied"

Guidelines In A Nutshell
1. Each approved gene symbol must be unique.
2. Symbols are short-form representations (or abbreviations) of the descriptive gene name.
3. Symbols should only contain Latin letters and Arabic numerals.
4. Symbols should not contain punctuation.
5. Symbols should not contain "G" for gene.
6. Symbols do not contain any reference to species, for example "H/h" for human.

Characters reserved for specific usage

Letters, or combinations of letters are used as prefixes or suffices in a symbol to represent a specific meaning and so their use for other meanings should be avoided where possible (Table 1). The following letter usage is not acceptable; H or h for human, G or g for gene. If the name of a gene contains a character or property for which there is a recognized abbreviation, the abbreviation should be used e.g. the single-letter abbreviation for amino acids used in aminoacyl residues. Other characters are also used within the symbol to represent genomic or genetic information (Table 1).
Table 1: Characters reserved for specific usage
Character
Meaning
AS
antisense
AP
associated/accessory protein
BP
binding protein
C
catalytic
CL
C terminal-like
CR
chromosome/critical region
C#orf#
chromosome # open reading frame #
D or DC
domain containing
FAM
family with sequence similarity
N or IN
inhibitor
NL
N terminal-like
IP
interacting protein
IT
intronic transcript
LG
ligand
L
like
LOH
loss of heterozygosity
MT or M
mitochondrial
OS
opposite strand
OT
overlapping transcript
P
pseudogene
Q
quantitative trait
R
receptor
RG
regulator
@
gene cluster in chromosomal region
#
gene family
Symbol Status

Each gene record in the HGNC database has one of five states:
a) Pending: gene symbols in progress.
b) Approved: official gene symbols that are publicly available.
c) Reserved : official gene symbols that are not publicly available, these will be released after a maximum period of six months.
d) Symbol Withdrawn: previous symbols for genes which now have different approved symbols.
e) Entry Withdrawn: for symbols which refer to a gene that has since been shown not to exist.

References:
http://www.genenames.org/guidelines.html#Introduction