GM25564

GM25564 LCL from B-Lymphocyte

Description:

CHOROIDEREMIA; CHM
CHM GENE; CHM

Affected:

No

Sex:

Female

Age:

30 YR (At Sampling)

Overview

Repository

NIGMS Human Genetic Cell Repository

Subcollection

Heritable Diseases
PIGI Consented Sample

Biopsy Source

Peripheral vein

Cell Type

B-Lymphocyte

Tissue Type

Blood

Transformant

Epstein-Barr Virus

Sample Source

LCL from B-Lymphocyte

Race

White

Ethnicity

Not Hispanic/Latino

Ethnicity

Finnish

Country of Origin

FINLAND

Family Member

Family History

Relation to Proband

half-sister

Confirmation

Molecular characterization before cell line submission to CCR

Species

Homo sapiens

Common Name

Human

Remarks

Unaffected carrier; pathogenic mutation in exon 13 of CHM gene: c.1609+2dupT; family history: mother is a carrier, a half-brother and a son are affected; mother

Characterizations

IDENTIFICATION OF SPECIES OF ORIGIN

Species of Origin Confirmed by LINE assay

Gene

CHM

Chromosomal Location

Xq21.2

Allelic Variant 1

300390.0001; CHOROIDEREMIA; CHM

Identified Mutation

c.1609+2dup; Sankila et al. (1992) described a point mutation that is responsible for choroideremia (303100) in the large Salla pedigree from northeastern Finnish Lapland that accounts for one-fifth of the world's choroideremia patients. They showed that the mutation is unique in that it is not responsible for choroideremia in any of the other Finnish pedigrees. The mutation was detected by single-strand conformation polymorphism (SSCP) analysis with subsequent sequencing of the relevant DNA segment. Sequencing showed insertion of a T within the splice donor site of the intron downstream of exon C, changing the normal sequence of AGgtaag to AGgttaag. A new restriction site for MseI was created by the mutation, thus permitting screening. Although the CHM gene is mainly expressed in the retina, choroid, and retinal pigment epithelium, low levels of transcripts are also found in lymphoblasts by means of polymerase chain reaction (PCR). This illegitimate transcription provides a convenient means of screening and analyzing the transcript. Lymphoblast-derived mRNA from a patient with what the authors referred to as the CHM*SAL mutation showed 2 aberrantly spliced mRNAs and no normal transcript.

Phenotypic Data

Remarks

Unaffected carrier; pathogenic mutation in exon 13 of CHM gene: c.1609+2dupT; family history: mother is a carrier, a half-brother and a son are affected; mother