GM27578

GM27578 iPSC from Fibroblast

Description:

PHENYLKETONURIA

Affected:

Yes

Sex:

Male

Age:

2 MO (At Sampling)

Overview

Repository

NIGMS Human Genetic Cell Repository

Subcollection

Heritable Diseases

Protocols

Protocol PDF

Biopsy Source

Skin

Cell Type

Stem cell

Cell Subtype

Induced pluripotent stem cell

Transformant

Reprogrammed (Sendai)

Sample Source

iPSC from Fibroblast

Race

White

Family Member

Relation to Proband

proband

Confirmation

Clinical summary/Case history

ISCN

46,XY[23].arr(1-22)x2,(X,Y)x1

Species

Homo sapiens

Common Name

Human

Remarks

Clinically affected; pyloric stenosis; normal level of dihydropteridine reductase in skin fibroblasts; donor subject is a compound heterozygote: one allele has a T>G transversion at nucleotide 896 in exon 8 of the PAH gene [896T>G] resulting in a substitution of cysteine for phenylalanine at codon 299 [Phe299Cys (F299C)] and a second allele has a C>T transition at nucleotide 1222 in exon 11 of the PAH gene [1222C>T] resulting in a substitution of tryptophan for arginine at codon 408 [Arg408Trp (R408W)]. Same subject as GM02406 (fibroblast). Researchers purchasing hiPSCs from the NIGMS Repository are responsible for any limited use label licenses (LULLs) applicable to the cell line purchased. The applicable LULL to this line is Sendai-CytoTune.

Characterizations

Induced Pluripotent Stem Cell

The parental cell line was recovered, reprogrammed to an induced pluripotent stem cell line, and expanded. The expanded line was evaluated for viability surface antigen expression and alkaline phosphatase activity. Pluripotency was assessed via embryoid body (EB) formation. Steady-state mRNA expression patterns of undifferentiated iPSC and EBs were determined via real-time PCR. Characterization data are included in the Certificate of Analysis.

Gene

PAH

Chromosomal Location

12q24.1

Allelic Variant 1

261600.0039; PHENYLKETONURIA

Identified Mutation

PHE299CYS; The mutant haplotype 8 occurs relatively frequently in Norwegian PKU patients (comprising 6% of mutant genes), whereas it is rare among other European PKU patients. Normal haplotype 8 genes have not been observed in any European population. Eiken et al. (1992) found that all mutant haplotype 8 chromosomes carried the phe299-to-cys mutation described briefly by Okano et al. (1989). A patient homozygous for the F299C mutation manifested severe PKU.

Gene

PAH

Chromosomal Location

12q24.1

Allelic Variant 2

261600.0002; PHENYLKETONURIA

Identified Mutation

ARG408TRP; DiLella et al. (1987) reported the molecular lesion associated with the RFLP haplotype-2 mutant allele. This defect is caused by a CGG-to-TGG transition in exon 12, resulting in an amino acid substitution (arg-to-trp) at residue 408 of PAH. Direct hybridization analysis of the point mutation using a specific oligonucleotide probe demonstrated that this mutation is in linkage disequilibrium with RFLP haplotype-2 alleles that make up about 20% of mutant PAH genes. This is presumably another example of CpG mutation. Woo (1988) provided a collation of the 43 RFLP haplotypes at the PAH locus identified to date. Ninety percent of all mutant alleles in Danes are associated with only 4 haplotypes, of which 2 had been fully characterized at the molecular level. The haplotypes are based on the combined pattern of presence or absence of sites of cutting by 7 restriction enzymes (BglIII, PvuII, EcoRI, MspI, XmnI, HindIII, and EcoRV), of which one, PvuII, has 2 cut sites. The GT-to-AT transition at the canonical splice donor site of intron 12, causing skipping of the preceding exon during RNA splicing, is associated with a mutant haplotype 3. The missense mutation involving an arginine-to-tryptophan substitution at residue number 408 of the enzyme is associated with mutant haplotype 2. Both mutant alleles are in linkage disequilibrium with the corresponding RFLP haplotypes throughout Europe, suggesting that 2 mutational events occurred on background chromosomes of the 2 haplotypes, followed by spread and expansion in the Caucasian population. In French Canadians, John et al. (1990) found that the arg408-to-trp mutation in exon 12 is associated with haplotype 1; in other populations, it occurs on haplotype 2. A CpG dinucleotide is involved in this mutation, compatible with a recurrent mutation, although gene conversion or a single recombination between haplotypes 2 and 1 is possible. Kalaydjieva et al. (1991) found this mutation in high frequency in Bulgaria, Lithuania, and eastern Germany, where it occurred on haplotype 2. Pooling of data on European populations suggested a Balto-Slavic origin of the arg408-to-trp defect, with an east-west cline in its frequency. Tsai et al. (1990) found this mutation in Chinese on a different haplotype, namely, no. 44. John et al. (1990) presented a tabulation of 20 PAH mutations showing 3 instances of putative recurrent mutation. Jaruzelska et al. (1991) found that haplotype 2 was most frequently (62%) associated with PKU alleles in Poland, where in the western part of the country the frequency of PKU is 1 in 5,000 live births. Furthermore, the arg408-to-trp mutation was in complete linkage disequilibrium with this haplotype. Similar observations have been made in other eastern European countries such as the former German Democratic Republic, Czechoslovakia, and Hungary. Zygulska et al. (1991) found similar results in southern Poland. Zygulska et al. (1991) found the arg408-to-trp mutation in 25 of 44 chromosomes from 22 unrelated Polish families with at least 1 PKU child. In 24 of these, mutation was on haplotype 2. A different mutation in the same codon, arg408-to-gln (261600.0038), has been described. Recurrent mutations in the 408 codon appear to occur; at least 2 different mutations (at least mutations on different RFLP haplotype background) have been identified in Chinese (Lin et al., 1992). Codon 408 (CGG) contains a CpG hotspot (Ramus et al., 1992). The R408W mutation is a CGG-to-TGG change in the coding strand; the R408Q mutation (261600.0038) is a GCC-to-GTC change in the noncoding strand. Ivaschenko and Baranov (1993) described a rapid and efficient PCR/StyI test for identification of this mutation.