In vivo histology and p.L132V mutation in KRT12 gene in Japanese patients with Meesmann corneal dystrophy

PURPOSE

To report genetic mutational analysis and in vivo histology of Meesmann corneal dystrophy.

STUDY DESIGN

Prospective, case control study.

METHODS

Six patients from three independent families with clinically diagnosed Meesmann corneal dystrophy were enrolled in this study. Slit-lamp biomicroscopy with fluorescein vital staining, anterior segment optical coherence tomography (AS-OCT), and in vivo laser confocal microscopy (IVCM) were performed on selected patients. Mutational screening for the keratin genes KRT3 and KRT12 was performed in all six patients and selected unaffected family members.

RESULTS

Slit-lamp biomicroscopy revealed numerous intraepithelial microcysts in all affected individuals. AS-OCT revealed hyperreflectivity and high corneal epithelial layer thickness (mean, 64.8μm) in all individuals tested (3/3). By using IVCM, multiple epithelial microcysts and hyperreflective materials (6/6), subepithelial nerve abnormalities (6/6), tiny punctate hyperreflective material (6/6), and needle-like hyperreflective materials (4/6) were observed in the corneal stromal layer. A heterozygous genetic mutation in the KRT12 gene (c.394 C>G, p.L132V) was identified in all six patients. No pathological mutation was observed in the KRT3 gene.

CONCLUSION

We identified a heterozygous genetic mutation (c.394 C>G, p.L132V) in the KRT12 gene in six Japanese patients with inherited Meesmann corneal dystrophy. This is the first study to confirm this genetic mutation in Japanese Meesmann corneal dystrophy patients. This mutation has been independently reported in an American Meesmann corneal dystrophy patient, confirming its pathogenicity. AS-OCT and IVCM proved to be useful tools for observing corneal epithelial layer pathology in this dystrophy. Furthermore, IVCM reveals corneal stromal layer pathological changes not previously reported in this dystrophy.

OPA1 mutations in Japanese patients suspected to have autosomal dominant optic atrophy

PURPOSE

To report three types of heterozygous mutations in the OPA1 gene in five patients from three families with autosomal dominant optic atrophy (ADOA, MIM#165500).

METHODS

DNA was extracted from the leukocytes of the peripheral blood. For mtDNA, mutations were examined at positions 11778, 3460 and 14484. For the OPA1 gene, the exons were amplified by PCR and mutations were detected by restriction enzymes or the dye terminator method.

RESULTS

We detected three types of OPA1 mutation but no mtDNA mutations. In the OPA1 gene, heterozygous frameshift mutations from codon 903 due to a four-base pair deletion in exon 27 were detected in three patients from one family (c.2708_2711delTTAG, p.V903GfsX905). A heterozygous mutation due to a three-base pair deletion in exon 17, leading to a one-amino acid deletion (c.1618_1620delACT, p.T540del), and a heterozygous mutation due to a one-base substitution in exon 11, leading to a stop codon (c.1084G>T, p.E362X), were detected in sporadic cases.

CONCLUSION

OPA1 mutations existed in three Japanese families with ADOA. After a detailed clinical assessment of the proband, the screening of the OPA1 gene may be helpful for precise diagnosis of ADOA, provided the relevant information of the family members is limited.

Electromigration Characteristics of Cu and Al Interconnections

Electromigration activation energies (Ea) of Al and Cu interconnections are strongly dependent on the grain boundary morphology, and it is pointed out that Ea of bamboo-like Al interconnection is not less than Ea of small grain Cu interconnections. Small resistance oscillatory changes caused by electromigration, which are classified into three categories; oscillation, downward spikes, and upward spikes, are investigated in detail. It seems most likely that oscillations correspond to annihilation and formation of the one void. It is also pointed out that downward spikes are local, while upward spikes are non-local. Dislocation dynamics such as generation, rapid transport and subsequent annihilation are considered to be origins of spikes.

A novel nonsense mutation in rhodopsin gene in two Indonesian families with autosomal recessive retinitis pigmentosa

PURPOSE

To report a novel, identical nonsense mutation in the rhodopsin (RHO) gene in two Indonesian families with autosomal recessive retinitis pigmentosa (arRP).

METHODS

Mutation screening for the RHO gene was performed in 38 unrelated patients with retinitis pigmentosa (RP) by direct sequencing. Clinical features were also characterized, through complete ophthalmologic examination. Family members of RP patients testing positive for the RHO gene were subjected to genetic and clinical examination. To assess the founder effect in the two families, haplotype analysis also was performed.

RESULTS

A novel homozygous nonsense mutation was detected in two patients by a G to A transition at nucleotide position 482 in exon 2 of the RHO gene, resulting in substitution of a tryptophan-to-stop at codon 161 (c.482G>A, p.W161X). Examination of family members of these 2 patients showed that the affected members were homozygous and unaffected carriers were heterozygous for the p.W161X mutation. Haplotype analysis revealed that members of the two families carried the same disease-associated variants in markers (IVS1 RHO and D3S2322). No p.W161X mutations were detected in 45 normal Indonesian subjects, nor were any mutations detected in exons 1-5 of the RHO gene in the remaining 36 RP patients.

CONCLUSION

We detected a novel, recessive nonsense mutation (p.W161X) in the RHO gene of two families through mutation screening of RHO in 38 Indonesian RP patients. Haplotype analysis suggested that p.W161X was the founder mutation.

Distribution of goblet cells and MUC5AC mRNA in the canine nictitating membrane

This study evaluated the distribution of goblet cells and the expression of MUC5AC mRNA in the canine nictitating membrane. The distribution of goblet cells in the nictitating membrane and temporal bulbar conjunctiva of beagle dogs was examined by histochemical analysis of impression cytology specimens and frozen sections. MUC5AC mRNA was detected by the reverse transcription polymerase chain reaction (RT-PCR). The distribution of MUC5AC mRNA was also examined by in situ hybridization using digoxigenin-labeled antisense and sense RNA probes. Histochemical analysis showed that the canine nictitating membrane epithelium contained many more periodic acid-Schiff positive goblet cells, particularly on the palpebral side, compared with the temporal bulbar conjunctiva. RT-PCR revealed that MUC5AC was expressed in both the nictitating membrane and in conjunctival tissue. When the distribution of MUC5AC mRNA was assessed by in situ hybridization, its expression was high on the palpebral side of the nictitating membrane and low in the temporal bulbar conjunctiva. MUC5AC mRNA expression corresponded with the distribution of goblet cells by histochemical examination. In conclusion, there were numerous goblet cells in the canine nictitating membrane epithelium, particularly on the palpebral side, and MUC5AC mRNA was expressed in the nictitating membrane epithelium at locations corresponding to the goblet cells.

Mutation analysis of CHST6 gene in Chinese patients with macular corneal dystrophy

PURPOSE

To examine the carbohydrate sulfotransferase 6 (CHST6) gene in Chinese patients with macular corneal dystrophy (MCD).

METHODS

Nineteen unrelated Chinese families with MCD, including 24 patients and 3 unaffected relatives, were examined. Genomic DNA was extracted from peripheral blood leukocytes. The coding region of the CHST6 gene was amplified by the polymerase chain reaction, and the DNA fragments were directly sequenced. Fifty unrelated normal Chinese volunteers served as the controls.

RESULTS

Eighteen different mutations in the CHST6 gene (including 15 novel mutations) were identified, of which 12 were missense mutations, 5 were nonsense mutations, and 1 was a frameshift mutation. Six families had homozygous mutation, and 13 families had compound heterozygous mutation. None of these mutations were detected in the normal controls.

CONCLUSIONS

CHST6 mutations may be responsible for the pathogenesis of MCD in Chinese patients. The Q298X mutation detected in 5 of 19 families (6 of 38 alleles, 15.8%) may be the founder mutation in Chinese patients. However, our findings also indicate a high level of allelic heterogeneity of the CHST6 gene in Chinese patients and in other ethnic groups.

Rainbow trout interleukin-2: cloning, expression and bioactivity analysis

In this study the rainbow trout (Oncorhynchus mykiss) interleukin-2 (IL-2) cDNA has been cloned, and its expression and bioactivity analysed in head kidney leucocytes. The IL-2 precursor encoded an open reading frame of 429 bp, that translates into a predicted protein of 142 aa, with a 20 aa signal peptide. The trout IL-2 had moderate protein homology (30.9% identity/48.3% similarity) with Fugu IL-2, the only IL-2 homologue identified in fish to date, with lower homology to avian (17.8% identity/23.2% similarity) and mammalian (34.2 identity/46.5% similarity) IL-2s. IL-2 expression was induced by the T cell mitogen PHA and by the mixed leucocyte reaction, where leucocytes from pairs of fish were cultured together for four days. Expression was also induced in vivo during bacterial (Yersinia ruckeri) infection. The Escherichia coli produced recombinant IL-2 was shown to increase the expression of two transcription factors, STAT5 and Blimp-1, known to be involved in IL-2 signalling in mammals, as well as IFN-gamma, gIP and IL-2 itself. The potential signalling pathways involved and possible use as an adjuvant for fish vaccines are discussed.

The sex determining loci and sex chromosomes in the family salmonidae

Salmonids are descended from a common ancestor that underwent an autotetraploidization event. After a whole genome duplication species could deal with sex determination by deleting one copy of SEX, the sex determining locus, or by recruiting a duplicated transcription factor to become a novel sex determining gene. It is not known which if any of these strategies salmonids adopted, but it appears that they all have primarily a genetic mechanism of sex determination with male heterogamety. The sharing of sex-linked markers on the X and Y chromosomes and the difficulty in identifying Y-specific markers indicate that X and Y chromosomes in salmonids have a large pseudoautosomal region and a small sex determining region. Linkage analyses suggest that either SEX differs in different lineages or else has remained the same and moved by transposition to different chromosomes. The identification of the sex chromosomes in salmonid species has not resolved this issue. It is clear that salmonids are at an early stage in sex chromosome differentiation and therefore provide a wonderful opportunity to study the evolution of sex determination. The availability of a reference salmonid genome sequence would provide an important resource for research in this area.

In vivo laser confocal microscopy findings and mutational analysis for Schnyder's crystalline corneal dystrophy

OBJECTIVE

To identify any mutation of the UbiA prenyltransferase domain-containing protein 1 (UBIAD1) gene in Japanese patients with Schnyder's crystalline corneal dystrophy (SCCD) and to investigate in vivo microstructural phenotype and genotype correlations using laser scanning confocal microscopy (Heidelberg Retina Tomograph 2 Rostock Cornea Module; Heidelberg Engineering GmbH, Dossenheim, Germany).

DESIGN

Small, comparative case series.

PARTICIPANTS

Three patients from 3 pedigrees (3 males) with clinically diagnosed SCCD and their relatives (2 males, 1 female) participated in this study.

TESTING

All participants were examined genetically and by slit-lamp biomicroscopy and in vivo laser confocal microscopy.

MAIN OUTCOME MEASURES

Genomic DNA from the patients and 100 unrelated healthy volunteers (200 chromosomes) was isolated from blood samples and used for mutation screening of the UBIAD1 gene. Selected confocal images of corneal layers were evaluated qualitatively for shape and degree of light reflection of deposits.

RESULTS

Novel mutations in the UBIAD1 gene (Y174C, K181R, and N233H) were identified. Additionally, cosegregation of the mutation (Y174C) and SCCD was confirmed in 1 pedigree, indicating that the mutation of the UBIAD1 gene is causative for SCCD. The 3 mutations were absent in all 200 control chromosomes. In vivo laser confocal microscopy demonstrated subepithelial highly reflective crystals in 4 cases; the shapes of the crystals were needle-shaped (3 cases) or rectangular (1 case). A phenotype and genotype correlation was demonstrated in 1 pedigree, and phenotypic heterogeneity (SCCD with or without crystals caused by a same mutation of Y174C in the UBIAD1 gene) also was demonstrated in 1 pedigree.

CONCLUSIONS

Nonsynonymous novel mutations in the UBIAD1 gene were detected in 3 unrelated Japanese pedigrees with SCCD, confirming the genetic heterogeneity of this disorder. In vivo laser confocal microscopy is capable of identifying characteristic corneal microstructural changes related to genetically mapped SCCD with high resolution, and phenotypic heterogeneity was presented. Further confocal and mutational analysis using a larger number of patients with SCCD is required to elucidate in vivo microstructural phenotype and genotype correlations.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

A novel mutation (967-970+2)delAAAGGT in the choroideremia gene found in a Japanese family and related clinical findings

PURPOSE

To investigate the choroideremia (CHM) gene of one affected male and one obligate carrier in a Japanese family with choroideremia, and to characterize the related clinical features.

METHODS

We examined one affected man and one carrier woman from a Japanese family. Genomic DNA was extracted from leukocytes of peripheral blood collected from the affected man and his daughter, who is an obligate carrier of choroideremia. Exons 1-15 of the CHM gene were amplified by polymerase chain reaction (PCR) and directly sequenced. We performed ophthalmic examinations including best-corrected visual acuity, slit-lamp examination, fundus examination, electroretinography, and Goldmann perimetry.

RESULTS

A novel (967-970+2)delAAAGGT mutation was detected in the CHM gene. The affected man was hemizygous and had night-blindness, chorioretinal atrophy spreading from the posterior pole to the mid-periphery, and bareness of the sclera. His daughter was a heterozygous carrier who had chorioretinal atrophy and mottled appearance of the retinal pigment epithelium.

CONCLUSION

A novel (967-970+2)delAAAGGT mutation existed in the CHM gene of a Japanese family with choroideremia.

A novel mutation in the cornea-specific keratin 12 gene in Meesmann corneal dystrophy

PURPOSE

To report a novel mutation in the keratin 12 gene (KRT12) found in a Japanese family in association with Meesmann corneal dystrophy (MECD).

METHODS

After informed consent was obtained, genomic DNA was extracted from the leukocytes of the peripheral blood of the proband, her affected father, normal mother, and 50 normal unrelated volunteers. Exons 1-8 of the KRT12 gene were amplified by polymerase chain reaction and directly sequenced.

RESULTS

A novel heterozygous T to G transversion at the second nucleotide position of codon 433 (CTG>CGG), resulting in the replacement of leucine by arginine at codon 433 of the KRT12 gene (L433R), was detected in the proband and her affected father but not in her normal mother or the 50 controls.

CONCLUSIONS

The novel L433R mutation of the KRT12 gene found in two members of this Japanese family caused MECD.

[Ocular pulse amplitude in patients with open-angle glaucoma, normal-tension glaucoma, and ocular hypertensionby dynamic observing tonometry]

PURPOSE

The aim of this study was to compare the ocular pulse amplitude (OPA) in patients with different types of glaucoma, and also to evaluate the usefulness of OPA for the elucidation of normal-tension glaucoma (NTG). OPA is thought to reflect choroidal circulation.

SUBJECTS

Sixty-six patients with normal-tension glaucoma (NTG), 52 patients with primary open angle glaucoma (POAG), 42 with ocular hypertension (OH) and 68 normal controls (NC) were enrolled in this study.

METHODS

OPA was measured in all participants by dynamic observing tonometry(DOT). The correlation between OPA and the following parameters [IOP, refraction error (Ref), blood pressure, pulse pressure (PP), MD of Humphrey field analyzer 30-2, type of groups] was analyzed by linear and multiple regression analysis (MRA). Multiple logistic regression analysis (MLR) was used to estimate the adjusted odds ratio (OR) for evaluation of the association between OPA (including other factors) and the proportion of NTG.

RESULTS

In MRA, IOP, Ref (< -3 D), PP and type of groups were significantly associated with OPA. The OPA in NTG was significantly lower than NC (p < 0.05). MLR demonstrated that OPA [OR 0.26 (95% CI, 0.12-0.57), p = 0.001] was associated with increased risk of having NTG.

CONCLUSIONS

Lower OPA in patients with NTG suggests that there is insufficiency of ocular circulation in NTG. Evaluation of OPA may be useful for the elucidation of the pathogenesis of glaucoma.

In vivo laser confocal microscopic findings of corneal stromal dystrophies

OBJECTIVE

To investigate in vivo laser confocal microscopic findings of genetically mapped corneal stromal dystrophies and their relationship to histopathologic findings.

METHODS

Seven patients with Avellino corneal dystrophy, 2 patients with lattice corneal dystrophy, and 2 patients with macular corneal dystrophy were examined genetically and using slitlamp biomicroscopy and in vivo laser confocal microscopy. Corneal specimens obtained after surgery in selected patients were histopathologically studied.

RESULTS

In Avellino corneal dystrophy (Arg124His mutation of human transforming growth factor beta-induced gene [TGFBI]), highly reflective granular materials with irregular edges were observed in the superficial stroma. In lattice corneal dystrophy (Arg124Cys and Leu527Arg mutations of TGFBI), highly reflective branching filaments of variable width were observed in the stroma. In macular corneal dystrophy (Ala217Thr mutation of the carbohydrate sulfotransferase gene [CHST6]), homogeneous reflective materials with dark striaelike images were observed throughout the stroma. All confocal findings correlated well with histopathologic findings.

CONCLUSIONS

In vivo laser confocal microscopy is capable of high-resolution visualization of characteristic corneal microstructural changes related to 3 types of genetically mapped corneal stromal dystrophies. The use of laser confocal microscopy may be valuable in the differential diagnosis of corneal stromal dystrophies, especially when diagnosis is otherwise uncertain.

A novel variant lattice corneal dystrophy caused by association of mutation (V625D) in TGFBI gene

PURPOSE

To characterize the molecular defect in the TGFBI gene in a Chinese family affected with an atypical lattice corneal dystrophy.

DESIGN

Case report and experimental study.

METHODS

Molecular genetic analysis was performed on the DNA extracted from peripheral leucocytes from a Chinese family with atypical lattice corneal dystrophy. Fifty normal unrelated subjects of Chinese origin were used as controls. All exons of the TGFBI gene were amplified by polymerase chain reaction and directly sequenced.

RESULTS

Bilateral, symmetrical, ridgy round pattern of opacities with uneven surfaces and thin lattice lines were noted in the proband. Analysis of exon 14 revealed a heterozygous T to A transition on codon 625. The mutation was not detected in the unaffected family member and 50 unaffected individuals.

CONCLUSIONS

The novel TGFBI gene mutation (V625D) is associated with an early-onset variant of lattice corneal dystrophy. This case highlights the utility of molecular genetic analysis in differentiating corneal dystrophies associated with an atypical phenotype from nondystrophic conditions.

[Clinical phenotype of a Japanese family with primary open-angle glaucoma caused by a Ala 363 Thr mutation in the MYOC gene]

BACKGROUND

Myocilin is a gene that causes primary open-angle glaucoma (POAG). We report a family whose members had an Ala 363 Thr mutation in the myocilin gene. We present the clinical phenotype of this family.

CASE

The proband was a 57-year-old man diagnosed with POAG. His younger sister (50 years old) was also diagnosed with POAG. Visual field impairment did not worsen and ocular pressure decreased with eyedrop treatment. Although two of their children in their 30s had ocular hypertension, they did not have any sign of glaucomatous optic neuropathy. Genetic analysis revealed that all four family members had an Ala 363 Thr mutation in myocilin gene.

CONCLUSION

Ala 363 Thr mutation was considered to be the cause of open-angle glaucoma. In this family, age at onset was comparatively high The two patients in their 30s had high intraocular pressure but no loss in visual acuity. The family members who had POAG and those who did not have POAG were not different from each other in the results of standard ocular examinations, only in age. Patients with this mutation will develop high intraocular pressure after 30 years of age and glaucomatous neuropathy after 50 years of age. When this gene mutation is detected in juvenile patients, careful follow-up and early therapy are necessary.

[Analysis of gene mutation in Chinese patients with Reis-Bücklers corneal dystrophy]

OBJECTIVE

To identify the mutation of the TGFBI gene in Chinese patients with Reis-Bücklers corneal dystrophy, and to study the relationship between the gene mutation and the clinical appearance.

METHODS

Ten patients and 2 unaffected family members from 2 unrelated families with corneal dystrophy were studied. Molecular genetic analysis was performed on DNA extracted from peripheral leucocytes, and exons 4 and 12 of the TGFBI gene were amplified by polymerase chain reaction for direct sequencing.

RESULTS

Both pedigrees showed an autosomal dominant inheritance. The clinical appearance of the cornea consisted of fine granular, subepithelial opacities which spread and become confluent with time, and resembled geographic type of Reis-Bücklers corneal dystrophy. Direct sequencing of all affected members revealed a G-to-T transition at codon 124 (CGC to CTC), producing R124L mutation of TGFBI gene.

CONCLUSIONS

R124L mutation of the TGFBI gene is found in two Chinese families with Reis-Bücklers corneal dystrophy. The phenotype of Reis-Bücklers corneal dystrophy in both families belongs to the geographic type. Molecular genetic approach may be useful for the proper diagnosis of this type of corneal dystrophy.

Novel mutation (V505D) of the TGFBI gene found in a Chinese family with lattice corneal dystrophy, type I

PURPOSE

To report a novel V505D mutation of the human transforming growth factor beta-induced (TGFBI) gene found in a Chinese family with lattice corneal dystrophy, type I (LCDI).

METHODS

Genomic DNA was extracted from peripheral leukocytes from eight affected and four unaffected members of a Chinese family with LCDI. Exons of the TGFBI gene were amplified by polymerase chain reaction and directly sequenced. Fifty normal Chinese individuals were also analysed as controls. Histopathological examination of a corneal button was performed after keratoplasty of the proband.

RESULTS

A heterozygous single-base-pair transversion (GTC to GAC, valine to aspartic acid) at codon 505 in exon 11 of the TGFBI gene (V505D) was detected in all of the affected members. No mutation was found in the unaffected members or in the 50 normal controls. The mutation cosegregated with the disease phenotype throughout three generations. Although a slit-lamp examination showed features of LCDI in most cases, the age at onset of the symptoms was several years later than that in cases of LCDI with an R124C mutation. By histopathological examination, numerous amyloid deposits were observed in the stroma, including beneath Bowman's membrane.

CONCLUSION

A novel V505D mutation in the TGFBI gene causes LCDI in this Chinese family. It is the fourth reported mutation of the TGFBI gene associated with LCDI.

Methotrexate-induced acute lung injury in a patient with rheumatoid arthritis

Methotrexate (MTX)-induced acute lung injury developed in a female patient with rheumatoid arthritis. She was successfully treated with high-dose glucocorticoid therapy. During her hospital stay, the serum concentration of surfactant protein (SP)-D, which was markedly elevated on admission, was finally normalized and the disease resolved. However, the serum concentration of Klebs von den Lungen (KL)-6 remained high. Although the mechanisms of lung injury by MTX have not been well defined, serial measurements of serum SPD might be useful for the clinical evaluation of drug-induced acute lung injury.

Induction of mononuclear cell infiltration into liver by Japanese herbal medicine

Juzen-Taiho-To (JTT) is a Japanese herbal medicine that has been administered mainly to patients weakened by long illness. Currently, it has also been used for cancer patients and showed antitumor effects that have been reported as phagocytosis enhancement, cytokine induction and antibody production. In this study, we examined the effect of oral administration of JTT in mice on the immunological restoration of the liver, especially focused on natural killer (NK) T-cell induction. Mice were grouped to receive JTT or placebo orally for a period of 1, 3 and 7 days. After sacrifice, the liver tissue was fixed, embedded and stained with hematoxylineosin and some antibodies by common staining methods. Transmission electron microscope (TEM) observation was also carried out. Although the JTT-treated mice had the same appearance as the non-JTT-treated mice, their livers were infiltrated by massive mononuclear cells, some of which were aggregated in clusters. Immunohistochemical staining revealed that there was abundant cytokine expression of interleukin (IL)-12 and massive infiltration of mononuclear cells with large granules in the liver of JTT-treated mice. Oral administration of JTT may induce the expression of IL-12 and be followed by immunological restoration such as NK T-cell induction in liver

Tear chymase in vernal keratoconjunctivitis

PURPOSE

To determine the levels of mast cell chymase and tryptase activity in the tears of patients with vernal keratoconjunctivitis (VKC).

METHODS

Subjects were 38 VKC patients and 18 healthy controls whose chymase and tryptase activity in tears was measured by enzyme assay. VKC severity was quantified based on the following clinical signs: papillary hypertrophy, conjunctival hyperemia, edema, punctate keratitis, Trantas dots, and mucus production. Of the 38 VKC patients, the degree of disease severity was mild in 13, moderate in 18, and severe in 7.

RESULTS

Mean chymase activity and standard deviation in tears was 0.23+/-0.07mU in mild VKC, 0.68+/-0.22mU in moderate VKC, 1.91+/-0.71 mU in severe VKC, and 0.11+/-0.05 mU in healthy controls. The increase in all VKC stages was statistically significant compared to that in healthy control. The degree of chymase activity in tears correlated significantly with VKC severity (r = 0.9245, p < 0.001). High tryptase activity was also detected in the tears of VKC patients, although increased tryptase activity in tears did not correlate with disease severity (r = 0.1999).

CONCLUSIONS

Chymase activity in tears may thus be a sensitive marker for determining the severity of VKC.

[Case of late onset and isolated lattice corneal dystrophy with Asn544Ser (N544S) mutation of transforming growth factor beta-induced (TGFBI, BIGH3) gene]

PURPOSE

To report a case of lattice corneal dystrophy (LCD) with Asn544Ser (N544S) mutation of the transforming growth factor beta-induced (TGFBI) gene.

CASE

A 68-year-old male patient with late-onset, sporadic LCD without corneal erosion. Amyloid deposits showing dot and lattice lines were seen in the mid to deep stroma. After obtaining appropriate informed consent, genomic DNA was amplified by polymerase chain reaction (PCR) and directly sequenced.

RESULTS

A heterozygous single base pair transition (AAT --> AGT), resulting in substitution of serine for asparagine at codon 544 of the TGFBI gene, was detected.

CONCLUSION

The case was classified as atypical type IV because of the late onset, lack of corneal erosion, and amyloid deposits in the mid to deep stroma.

Mutations in the membrane component, chromosome 1, surface marker 1 (M1S1) gene in gelatinous drop-like corneal dystrophy

PURPOSE

To report mutations in the membrane component, chromosome 1, surface marker 1 ( M1S1) gene in two members of the same family who showed symptoms of gelatinous drop-like corneal dystrophy (GDLD).

METHODS

DNA was extracted from leukocytes of peripheral blood of the two affected members of the family and from controls, and the coding region of M1S1 was amplified by polymerase chain reaction (PCR). The PCR products were analyzed by direct sequencing. Normal and mutant M1S1 expression vectors were constructed and transfected into CHO cells to identify the cellular location of the gene products.

RESULTS

The affected members had compound heterozygous mutations consisting of a nonsense change at codon 84 (K84X) and a missense mutation resulting in a substitution of arginine for cysteine at codon 108 (C108R). Neither of these mutations was found in the 50 controls. Protein expression analysis showed that the C108R product was distributed diffusely in the cytoplasm, whereas the normal gene product accumulated at cell-to-cell adhesion borders.

CONCLUSION

These data indicate that the K84X and C108R mutations in M1S1 cause GDLD.

Analysis of COL8A2 Gene Mutation in Japanese Patients with Fuchs’ Endothelial Dystrophy and Posterior Polymorphous Dystrophy

PURPOSE

To determine whether Japanese patients with Fuchs' endothelial corneal dystrophy (FECD) and posterior polymorphous dystrophy (PPMD) carry mutations in the COL8A2 gene, and to investigate the possible pathogenicity of the COL8A2 gene in these corneal dystrophies.

METHODS

DNA analysis of the COL8A2 gene was performed in 15 unrelated Japanese patients with FECD, and 5 patients with PPMD using polymerase chain reaction and direct sequencing. Mutation screenings were also performed in 36 unrelated normal volunteers as controls, as well as slit-lamp and specular microscopy.

RESULTS

Two types of heterozygous missense mutations of the COL8A2 gene (R155Q and T502M) in 5 of 15 FECD probands (R155Q, 3/30 chromosomes, 10.0%; T502M, 3/30 chromosomes, 10.0%) were found. No mutation was detected in the coding region of the COL8A2 gene in the remaining 10 patients with FECD nor in any of the 5 patients with PPMD. These two mutations were also found in normal Japanese volunteers (R155Q, 5/72 chromosomes, 6.9%; T502M, 11/70 chromosomes, 15.7%). The chromosomal frequency of the two mutations was not significant between the patients and normal controls.

CONCLUSIONS

The R155Q and T502M mutations of COL8A2 may not be the causative defect in the Japanese FECD and PPMD patients examined in this study.

Compound heterozygous mutations of M1S1 gene in gelatinous droplike corneal dystrophy

PURPOSE

To report the genetic findings in a Chinese patient diagnosed with gelatinous droplike corneal dystrophy (GDLD).

DESIGN

Case report and experimental study.

METHODS

Molecular genetic analysis was performed on the DNA extracted from peripheral leukocytes from a Chinese patient with GDLD and his unaffected parents. Fifty healthy, unrelated, Chinese participants were used as control subjects. The M1S1 gene was amplified by polymerase chain reaction and directly sequenced.

RESULTS

The patient was clinically diagnosed with GDLD. Direct sequencing of the M1S1 gene revealed heterozygous changes in both alleles, a novel Y184C mutation on one allele and a Q118X mutation on the other that was reported as a founder mutation in the Japanese population. The patient's unaffected parents showed only the heterozygous Q118X or Y184C mutation. The mutation was not detected in the 50 unaffected subjects.

CONCLUSIONS

This is the first genetic analysis of a Chinese patient with GDLD. Because the compound heterozygote mutations Q118X and Y184C cosegregated with the phenotype, they are likely the cause of GDLD in this patient.

Mutation analysis of the TGFBI gene in Vietnamese with granular and Avellino corneal dystrophy

PURPOSE

Mutations of the human transforming growth factor beta-induced gene (TGFBI) were reported to cause granular (GCD) and Avellino (ACD) corneal dystrophy in various nationalities. In this study we examined the TGFBI gene in a Vietnamese population with GCD and ACD.

METHODS

Eight unrelated Vietnamese families, including 20 affected and 24 unaffected individuals, were examined; 50 normal Vietnamese individuals were used as controls. Genomic DNA was extracted from peripheral blood leukocytes. The TGFBI gene was analyzed using the polymerase chain reaction and direct sequencing. The corneal button was studied.

RESULTS

Slit-lamp examination revealed typical features of GCD in most cases. A few features of ACD and a patient with an atypical form of GCD were also seen. Histopathological analysis of a GCD cornea showed deposits that stained bright red with Masson trichrome. Sequencing revealed three distinct mutations: R555W in six families, R124H in one family, and D123H in another.

CONCLUSIONS

R555W and R124H mutations were co-segregated with the disease phenotype and thus caused GCD and ACD, respectively, in the families studied. The R555W detected in six of the eight families indicates that the GCD phenotype may be the most common in Vietnamese individuals, unlike in other Asians (Japanese and Korean), where ACD is most common (>90%). The D123H mutation may cause an atypical variant of GCD.

Mutation analysis of the carbohydrate sulfotransferase gene in Vietnamese with macular corneal dystrophy

PURPOSE

Mutations in a new carbohydrate sulfotransferase gene (CHST6) encoding corneal N-acetylglucosamine-6-sulfotransferase (C-GlcNac-6-ST) have been identified as the cause of macular corneal dystrophy (MCD) in various ethnicities. This study was conducted to examine the CHST6 gene in Vietnamese with MCD.

METHODS

Nineteen unrelated families, including 35 patients and 38 unaffected relatives were examined clinically. Blood samples were collected. Fifty normal Vietnamese individuals served as control subjects. Genomic DNA was extracted from leukocytes. Analysis of the CHST6 gene was performed with polymerase chain reaction and direct sequencing. Corneal buttons were studied histopathologically.

RESULTS

A slit lamp examination revealed clinical features of MCD with gray-white opacities and stromal haze between. On histopathology, corneal sections showed positive staining with colloidal iron. Sequencing of the CHST6 gene revealed six homozygous and three compound heterozygous mutations. The homozygous mutations, including L59P, V66L, R211Q, W232X, Y268C, and 1067-1068ins(GGCCGTG) were detected, respectively, in two, one, eight, one, one, and two families. Compound heterozygous mutations R211Q/Q82X, S51L/Y268C, and Y268C/1067-1068ins(GGCCGTG) were identified, each in one family. A single heterozygous change at codon 76 (GTG-->ATG) was detected in family L, resulting in a valine-to-methionine substitution (V76M). None of these mutations was detected in the control group.

CONCLUSIONS

Mutations identified in the CHST6 gene cosegregated with the disease phenotype in all but one family studied and thus caused MCD. Among these, the R211Q detected in 9 of 19 families may be the most common mutation in Vietnamese. These data also indicate that significant allelic heterogeneity exists for MCD.

Mutations in the CHST6 gene in patients with macular corneal dystrophy: immunohistochemical evidence of heterogeneity

PURPOSE

Macular corneal dystrophy (MCD) is an autosomal recessive disorder leading to severe visual impairment. The carbohydrate sulfotransferase 6 (CHST6) gene, which encodes the corneal N-acetylglucosamine 6-O-sulfotransferase on 16q22 has been identified as a causative gene for MCD. The purpose of this study was to identify mutations in CHST6 in Japanese patients with MCD and evaluate them by means of immunohistochemistry.

METHODS

CHST6 was screened in 7 patients and 45 healthy control subjects. Genomic DNA was isolated, and the open reading frame (ORF) of CHST6 was amplified by polymerase chain reaction (PCR). PCR products were analyzed by direct sequencing and restriction enzyme digestion. Immunohistochemistry with a monoclonal anti-keratan sulfate (KS) antibody was performed on corneas of four patients from three families.

RESULTS

Three novel mutations (P204Q, R205L, and R177H) and two previously reported mutations (R211W and A217T) were identified in the ORF of CHST6. P204Q, R205L, and R211W were found to be homozygous and R177H and A217T compound heterozygous with R211W on another allele. Immunohistochemistry revealed that R205L homozygous cornea had negative reactivity against the anti-KS antibody, representing type I MCD, and that R211W homozygous and R211W/A217T compound heterozygous corneas had negative or very weak reactivity in the stroma with antibody positive deposits, which were distinct from any previously reported types.

CONCLUSIONS

Two mutations (homozygoous R211W and compound heterozygous R211W/A217T) should be subclassified immunohistochemically into new phenotypes of MCD. This heterogeneity could provide further insights into the pathogenesis of MCD.

Identification of novel mutations of the CHST6 gene in Vietnamese families affected with macular corneal dystrophy in two generations

PURPOSE

To report the clinical and genetic findings of Vietnamese families affected with macular corneal dystrophy (MCD) in 2 generations.

METHODS

Two families, including 7 patients and 3 unaffected members, were examined clinically. Blood samples were collected. Fifty normal Vietnamese individuals were used as controls. Genomic DNA was extracted from leukocytes. Analysis of the carbohydrate sulfotransferase (CHST6) gene was performed using polymerase chain reaction and direct sequencing.

RESULTS

The typical form of MCD was recognized in family B, in which sequencing of CHST6 gene revealed an nt 1067-1068ins(GGCCGTG) mutation (frameshift after 125V) homozygously in MCD patients and heterozygously in the unaffected members. Family N also showed clinical features of MCD, moderate in the mother but severe in the affected son. Sequencing revealed a single heterozygous Arg211Gln in the mother, compound heterozygous Arg211Gln+ Gln82Stop in the affected son, and heterozygous Arg211Gln mutation in the unaffected members. The identified mutations in these pedigrees were excluded from normal controls.

CONCLUSIONS

The novel frameshift and compound heterozygous mutations might be responsible for MCD in the families studied. The phenotypic variation between affected parents and offspring was unclear. In family N, severe MCD phenotype seen in the affected son may be due the fact that he had an early stop codon mutation (Gln82Stop).

OPA1 gene mutations in Japanese patients with bilateral optic atrophy unassociated with mitochondrial DNA mutations at nt 11778, 3460, and 14484

PURPOSE

To report mutations in the OPA1 gene in Japanese patients with bilateral optic atrophy unassociated with mitochondrial DNA mutations at nt 11778, 3460, and 14484.

METHODS

Twelve unrelated patients with bilateral optic atrophy and 100 healthy controls were examined. Each exon of the OPA1 gene was amplified by polymerase chain reaction (PCR). All PCR products were sequenced.

RESULTS

Of the 12 patients, 2 had nonsense mutations of the OPA1 gene (nt 1039G --> T and nt 1096C --> T, leading to Glu347Stop and Arg366Stop, respectively). These nonsense mutations were not found in the 100 healthy controls. Two of the patients had silent mutations of OPA1 gene (nt 1177T --> G and nt 1923G --> A causing no amino acid change).

CONCLUSIONS

The mutations (Glu347Stop and Arg366Stop) of the OPA1 gene are involved in the pathogenesis of bilateral optic atrophy in Japanese patients.

H626R and R124C mutations of the TGFBI (BIGH3) gene caused lattice corneal dystrophy in Vietnamese people

BACKGROUND/AIMS

Mutations of the human transforming growth factor beta induced gene (TGFBI) were reported to cause lattice corneal dystrophy (LCD) in various nationalities. This study analysed the TGFBI gene in Vietnamese people with LCD.

METHODS

13 unrelated families, including 34 patients and 21 unaffected members were examined. 50 normal Vietnamese people served as controls. Blood samples were collected. Genomic DNA was extracted from leucocytes. Analysis of TGFBI gene was performed using the polymerase chain reaction and direct sequencing. Corneal buttons were studied histopathologically.

RESULTS

Two clinically distinguishable forms of LCD were revealed: one was typical of LCDI; the other was characterised by the late onset, thick lattice lines, and asymmetry between two eyes. Sequencing of the TGFBI gene revealed R124C mutation in three families and H626R mutation in 10 families. Congo red staining of the H626R-LCD cornea showed amyloid deposits in the subepithelial and stromal layers.

CONCLUSIONS

R124C and H626R mutations of TGFBI gene caused LCD in Vietnamese people. R124C, a common cause of LCDI in many nationalities, was relatively rare, whereas H626R reported in several white people but not yet in Asians was most common (>75%) in Vietnamese people. Since the phenotype caused by H626R represents a new variant intermediate between LCDI and LCDIIIA, we proposed to consider it as LCD type IIIB.

A novel mutation of the TGFBI gene found in a Vietnamese family with atypical granular corneal dystrophy

BACKGROUND

Mutation of the human transforming growth factor beta-induced (TGFBI) gene causes granular corneal dystrophy (GCD) in various ethnic groups. In this report, we identify the genetic defect on the TGFBI gene in a Vietnamese family with atypical GCD .

CASES

The patient and her relatives were examined clinically. Genomic DNA was extracted from blood leukocytes. Fifty normal Vietnamese were used as controls. Analysis of the TGFBI gene was performed using polymerase chain reaction and direct sequencing.

OBSERVATIONS

The 42-year-old proband clinically showed multiple white dot-like opacities scattered in the anterior and mid-stroma of the central cornea. Unlike GCD, these deposits were smaller, localized deeper and less severe. DNA analysis revealed a nucleotide transversion at codon 123 (GAC --> CAC), causing Asp --> His substitution (D123H). This mutation was also detected in 3 out of 5 unaffected family members, but was absent in the 50 normal controls.

CONCLUSIONS

The novel D123H mutation of the TGFBI gene was not co-segregated with GCD in the family studied, and did not exist in the control population. It probably was a disease-causing mutation, thus expected to cause a novel variant of GCD in the proband. The detection of the D123H mutation in three unaffected family members indicates that it has low penetrance for GCD.

Multiplex polymerase chain reaction for detection of herpes simplex virus type 1, type 2, cytomegalovirus, and varicella-zoster virus in ocular viral infections

PURPOSE

To detect simultaneously herpes simplex virus type 1 (HSV-1), type 2 (HSV-2), cytomegalovirus (CMV), and varicella-zoster virus (VZV) in ocular specimens suspected of indicating viral infection, and to compare the results of multiplex polymerase chain reaction (PCR) with those of uniplex PCR.

METHODS

Forty specimens, collected from 33 patients with clinically suspected herpes virus ocular infection, were tested. DNA was extracted from the specimens and amplified by multiplex and uniplex PCR.

RESULTS

Both multiplex PCR and uniplex PCR gave the same results. Nineteen (19/33, 57.6%) patients were PCR-positive, among whom HSV-1 was detected in 13 (13/19, 68.4%) patients, and VZV in 6 (6/19, 31.6%) patients.

CONCLUSION

These results demonstrated that multiplex PCR is as reliable as uniplex PCR, and is an accurate and a cost-saving method to identify several agents from a single specimen.

Molecular cloning of ELOVL4 gene from cynomolgus monkey (Macaca fascicularis)

ELOVL4, elongation factor of very long chain fatty acids-4, is known to be responsible for autosomal dominant macular degeneration and Stargardt-like macular degeneration. In this study, we cloned the monkey homologue of ELOVL4 and determined the cellular and tissue distribution of the gene product. Sequence analysis of the monkey ELOVL4 gene revealed a high degree of homology between human and monkey. The cloned full-length cDNA of monkey ELOVL4 encoded 314 amino acids, the same length as human and two amino acids longer than mouse. The monkey ELOVL4 conserved the characteristics typical of the super family of ELO enzymes involved in the metabolism of membrane-bound fatty acid elongation. Real-time quantitative PCR demonstrated that the monkey ELOVL4 gene was highly expressed in restricted tissue-specific fashion, not only in the retina but also in the skin (90% of retina) and thymus (111% of retina). Immunohistochemical analysis detected signals predominantly in the photoreceptor layer of the monkey retina.

[Gene transfer into corneal endothelial cells by Helios gene gun]

PURPOSE

To examine the efficiency of particle-mediated gene transfer into rabbit corneal endothelium with a Helios gene gun system.

METHODS

Using gene gun, plasmid DNA coding for green fluorescent protein(GFP) was transferred into cultured rabbit endothelial cells and rabbit corneal grafts from their endothelial site. Then the transferred corneas were transplanted as autografts. The GFP expression was detected by fluorescence microscopy. Histological examination of corneas was performed by light microscope and scanning electron microscope.

RESULTS

In cultured rabbit endothelial cells, the transfection efficiency without damage to cells was about 7% under optimized helium pressure of 120 psi. In ex vivo, the GFP expression was limited to endothelial cells of the grafts at 140 psi. The histological findings from light and scanning electron microscopy of the grafts showed no severe mechanical damage in endothelial cells penetrated by gold particles.

CONCLUSIONS

The helios gene gun system successfully transferred genes into corneal endothelial cells. However, further studies will be required to obtain the stable results of the particle mediated gene transfer into the endothelial cells of corneal grafts for clinical practice.

A novel mutation of M1S1 gene found in a Vietnamese patient with gelatinous droplike corneal dystrophy

To identify the genetic defect in the M1S1 gene responsible for gelatinous droplike corneal dystrophy (GDLD) in a Vietnamese family.Experimental study. Blood samples were collected from a patient and the unaffected members of a GDLD-affected family. Fifty normal unrelated subjects of Vietnamese origin were used as controls. Genomic DNA was extracted from blood leukocytes. DNA analysis of the M1S1 gene was performed using polymerase chain reaction and direct sequencing. Sequencing of the M1S1 gene revealed a deletion of a 12-base-pair (bp) fragment from nucleotide positions 772 to 783 [772 to 783del(ATCTATTACCTG)], resulting in a loss of four amino acids at codons 258 to 261 (L258-liter261del). Yet, an insertion of nucleotide T in place of the missing sequence (772insT) was found. This combined mutation was homozygous in the GDLD-affected patient and heterozygous in his unaffected son and younger sister. Such genetic alteration was excluded in the control population. This is the first report of a mutational analysis performed in a Vietnamese patient with GDLD. In this family, the novel 772 to 783del(ATCTATTACCTG) + 772insT mutation on the M1S1 gene was well cosegregated with the phenotype and thus expected to cause GDLD. Although the M1S1 gene was responsible for GDLD in Vietnamese patients, the mutation found here is completely different from that previously reported in Japanese patients, where GDLD is most frequently seen.

[Estimation of patient visit rate and incidence of keratoconus in the 23 wards of Tokyo]

PURPOSE

To estimate the patient visit rate and the incidence of keratoconus in the 23 Wards of Tokyo.

SUBJECTS AND METHODS

We searched for keratoconus patients with questionnaires sent to 141 hospitals in the 23 Wards of Tokyo. The patient visit rate was estimated using the number of patients from 15 to 44 years old. The incidence was estimated from the number of patients in whom the onset of the disease was at the age 15 to 34.

RESULTS

Three hundred and twenty-five patients (205 males and 120 females) were found during a survey of three months. The return rate of the questionnaires was 49.6%. Male/female ratio was 1.7/1.0. The patient visit rate of keratoconus during three months was estimated to be 12.4 x 10(-5) (1/8,100) in males and 6.7 x 10(-5) (1/15,000) in females. The annual incidence was estimated to be 12.1 x 10(-5) (1/8,300) in males and 5.6 x 10(-5) (1/17,900) in females. 6.5% of the patients were given corneal transplants.

CONCLUSION

We estimated the patient visit rate and the incidence of keratoconus on the basis of the survey of hospitals of the 23 Wards of Tokyo during a 3-month period. Compared with the previous reports, our data suggests that the proportion of women is increasing in patients with keratoconus, and that the ratio of patients who have to receive corneal transplant therapy are decreasing. A large-scale epidemiological study is required.

[Gelatinous drop-like corneal dystrophy: mutation analysis of membrane component, chromosome 1, surface marker 1]

PURPOSE

To investigate mutation in membrane component, chromosome 1, surface marker 1(M1 S1) gene for patients and unaffected relatives of gelatinous drop-like corneal dystrophy(GDLD).

MATERIALS AND METHODS

We performed mutation analysis for 11 patients and 18 unaffected relatives from 7 unrelated families with GDLD. They were followed at the Department of Ophthalmology, Juntendo University, Tokyo, and St. Luke's International Hospital, Tokyo.

RESULTS

Ten patients including the affected members of 6 families were detected to be homozygotes by transition of a C to T at nucleotide position 352, replacing a glutamine at codon 118 with a stop codon (Q118X), and unaffected relatives were heterozygous for the mutation. One patient and his parents and brother from one family have had no mutation in open reading frame of the M1S1 gene.

CONCLUSIONS

In these 6 families the genotypes of Q118X mutation on M1S1 gene were co-segregated with the phenotype. For the patients who have had no mutation, we need further investigation of the 5' upper site, and it is possible that there is another candidate gene for GDLD.

Transferrin-polyethylenimine conjugate, FuGENE6 and TransIT-LT as nonviral vectors for gene transfer to the corneal endothelium

PURPOSE

To investigate the efficacy and pathogenicity of three commercially available nonviral DNA vectors for gene transfer to the corneal endothelium.

METHODS

Corneas obtained from New Zealand White rabbits were cultured ex vivo. For cell culture, the corneal endothelial cells were removed and cultured in vitro under standard conditions. Using the vectors, culture cells or ex vivo corneas were transfected with plasmid DNA coding for green fluorescent protein (GFP). Expression of the transduced gene was monitored by fluorescence microscopy. Transfection efficiency was estimated as the percentage of GFP-positive cells identified. The viability and morphology of the endothelium were also examined.

RESULTS

Transferrin-polyethylenimine conjugate was effective in vitro but not ex vivo. FuGENE6 and TransIT-LT mediated the transfer of GFP gene both in in vitro and in ex vivo culture. Their efficiency estimated at day 3 was 28.8% and 38.8% in vitro, and 8.1% and 8.8% ex vivo, respectively. Viability staining revealed no dead cells. Morphological study showed no apparent alteration.

CONCLUSIONS

FuGENE6 and TransIT-LT are safe, simple to use, and may be useful alternative methods for gene transfer to the corneal endothelium, avoiding certain side effects of viral vectors. As the efficiency could be enhanced, these nonviral vectors may be promising for practical application.

Transthyretin Ser-44 mutation in a case with vitreous amyloidosis

PURPOSE

To report a case of vitreous amyloidosis associated with a transthyretin Ser-44 mutation.

METHODS

Interventional case report. A 44-year-old Japanese woman had a 2-month history of visual disturbance in both eyes. The vitreous and conjunctival specimens were subjected to histopathological examination. DNA was isolated from peripheral blood cells of the patient. The transthyretin gene was amplified and directly sequenced.

RESULTS

The vitreous and conjunctiva specimens showed typical light microscopic features of amyloidosis. Direct sequencing of the transthyretin gene revealed a single base-pair substitution, which results in an amino acid substitution at position 44, phenylalanine to serine (transthyretin Ser-44).

CONCLUSION

Transthyretin Ser-44 may cause vitreous amyloidosis.

Corneal dystrophies in Japan

Recent advances in molecular genetics have increased our understanding of the role of genes. Four autosomal dominant corneal dystrophies (CDs); granular CD (GCD), Avellino CD (ACD), lattice CD (LCD), and Reis-Bücklers CD (RBCD) were mapped to the long arm of chromosome 5 (5q31). These four diseases were shown, in a Caucasian series, to result from different missense mutations in the TGFBI (BIGH3, keratoepithelin) gene. The same mutations were also detected in Japanese patients, from a different ethnic background. Gelatinous drop-like corneal dystrophy (GDLD), on the other hand, which was found in Japanese patients in 1914, is a rare autosomal recessive disorder characterized by corneal amyloidosis. Parents of the patients had a markedly higher frequency of consanguineous marriages than the general population. The gene responsible for GDLD, the membrane component, chromosome 1, surface marker 1 (M1S1) gene was mapped to the short arm of chromosome 1(1p). Four deleterious mutations in this gene were detected in Japanese patients. We review here additional studies on mutations of the TGFBI and M1S1 genes found in Japanese patients. In the TGFBI gene, nine different mutations were detected in Japanese patients with GCD, ACD, LCD, or RBCD. The codons R124 and R555 of the TGFBI gene were hotspots in Japanese patients, of whom many were ACD patients with the R124H mutation. New mutations responsible for LCD were detected in the TGFBI gene of patients with LCD, in addition to the P501T mutation in LCD type IIIA found earlier. These studies showed a clear genotype/phenotype correlation associated with the TGFBI gene. In the M1S1 gene, the Q118X mutation was the most common alteration, and a founder mutation in Japanese GDLD patients, as previously reported. Ninety-two percent of the mutated alleles were the Q118X.

Cloning and characterization of cDNA clones encoding membrane-bound and potentially secreted major histocompatibility class I receptors from walleye (Stizostedion vitreum)

Major histocompatibility (MH) gene polymorphism has been used to type populations of humans, mice, and fish. Walleye ( Stizostedion vitreum) comprise an economically important fishery in Lake Erie, but whether those in the western basin form a single population or separate shoal- and river-breeding populations is not known. To develop MH gene markers for use in defining their population structure, we constructed a head kidney cDNA library from which five full-length class I heavy-chain clones were isolated and sequenced. Although they came in roughly three sizes, 1300, 1400, and over 2000 bp, the clones all exhibited a high degree of sequence similarity to each other and to known teleost MH class I cDNAs in the area encoding the extracellular domains, but showed dramatic differences in their transmembrane and cytoplasmic domains. One clone had an AG repeat that eliminated the hydrophobicity of the transmembrane domain, indicating that it may encode a secreted class I receptor. The other four clones encode three distinctly different cytoplasmic domains. The two clones that encode the same cytoplasmic domain resemble those of the known teleost MH class I sequences the most. Southern blotting indicated that there were four copies of the gene present in the walleye genome. Northern blotting showed that class I MH genes are expressed in most tissues and mRNAs of all three size classes can be detected. A preliminary survey of the polymorphism of these genes indicates that they will provide useful markers for differentiating fish stocks.

Organization of the NKEF gene and its expression in the common carp (Cyprinus carpio)

Natural killer enhancing factor (NKEF) is a member of the newly defined peroxiredoxin (Prx) family. Its functions are to enhance the cytotoxic capacity of natural killer cells and to prevent DNA and protein from being damaged by oxidative stress in the presence of thiol compounds. However, little is known about the structure and function of NKEF in lower vertebrates. We have recently cloned a cDNA encoding NKEF from the common carp (Cyprinus carpio) by use of suppression subtractive hybridization (SSH). In the present study, we used PCR to obtain a genomic DNA which covers the entire coding region of carp NKEF. In the 3363bp-long genomic sequence, six exons and five introns were identified. The carp NKEF gene has splice donor/acceptor site sequences at the boundaries of exons and introns, and contains two Val-Cys-Pro (VCP) motifs. The exon/intron organization of the carp NKEF gene shows complete conservation with other members of the Prx family. Genomic Southern blotting analyses suggest that carp has multiple copies of the NKEF gene. RT-PCR analyses reveal that carp NKEF has very different expression levels not only in tissues but also from individuals.