ARTICLE
Auteur(s) : Caie Zhang*2,
Yunhua
Deng1, Xingping Chen1, Xiongwen
Wu2, Wenhua Jin1, Hao Li1,
Chunying Yu3, Ying Xiong1, Liyi
Zhou1, Yingling Chen1
1Department of Dermatology, Tongji Hospital
affiliated to Tongji Medical College, Huazhong University of
Science and Technology, Wuhan 430030, China
2Department of Immunology, Tongji Medical College,
Huazhong University of Science and Technology, Wuhan 430030,
China
3Faculty of Forensic Medicine, Tongji Medical College,
Huazhong University of Science and Technology, Wuhan 430030,
China
accepté le 1 Février 2006
Familial progressive hyperpigmentation (FPH, MIM 145250), which is
also sometimes named melanosis universalis hereditaria, was first
described by Chernosky et al. [1] in 1971. Its classical feature
was hyperpigmented patches in the skin which were present at birth
or in early infancy and increased in size and number with age. In
the end, a large percentage of the skin was involved.
Hyperpigmentation always occurred on the face, neck, trunk, limbs,
lips, oral mucosa, palms and soles. It is not associated with any
systemic disease, only disorders of pigmentation seems to be
involved in for FPH. FPH has been demonstrated to be an autosomally
dominant cutaneous disorder [2, 3]. No association of FPH was found
by genetic studies with markers of ABO, Rh and HLA, nor chromosome
aberration by cytogenetic studies with karyotype analysis [1,
4].Although FPH has been shown to be a monogenic trait of an
autosomal dominant pattern, no linkage information for this disease
has been reported to date. In this study, we undertook a linkage
analysis with microsatellite polymorphic markers−short tandem
repeat (STR) in a three-generation Chinese family with FPH,
residing in Hubei Province, central China. The result of this study
indicates the FPH locus is linked to the short arm of chromosome
19.
Materials and methods
Pedigree
The subjects are from a three-generation family consisting of 17
individuals, residing in a rural area of Hubei Province, central
China. The family is of Chinese Han origin. There are 6 affected
individuals in this family, including 3 males and 3 females (figure 1). The
pedigree chart shows that the FPH is an inherited monogenic trait
of an autosomal dominant pattern. The earliest onset of the disease
in the family was at the age of 5. Affected members in the pedigree
had typical clinical manifestations of FPH. All of them have normal
mental abilities and no systemic disease, such as gastrointestinal
ailment, liver and kidney disease. All 17 family members were
included in the study, among whom, the eldest member is 60 and the
youngest is 6. Written informed consent was obtained from all
participants or their parents included in this study.
The proband (II5), a 32-year-old man, had a typical
manifestation and history of FPH. The hyperpigmentation can be
observed on his hands (figure 2A), forehead (figure 2B), back of
feet (figure 2C)
and trunk (figure
2D). A few light brown spots appeared on the back of his
hands and eyelids when he was 7. About 2 years later, some similar
lesions appeared on his neck, forehead and the back of his feet. As
the disease progressed with age, these lesions slowly increased in
size and number. They also became darker. At the same time, these
hyperpigmented lesions spread to his trunk, arms, legs, palms and
soles. Among them, no pits and hypopigmented macules were found.
There were no pigmented lesions found in the conjunctivae or buccal
mucosa. There was normal hair, sweating and feeling in these
hyperpigmented areas. A skin biopsy from the right-shoulder
hyperpigmented area was performed. Histological examination
revealed a slight hyperkeratosis with a marked increase in the
amount of melanin in the epidermis, especially in the basal cell
layer and at the tips of the rete ridges. The dermis was normal
(figures 3A and
B).
Genotyping
10 mL blood samples were taken from all 17 individuals with
EDTA-vacutainer. DNA was isolated from peripheral blood cells.
Genome screening was performed using 176 STR microsatellite markers
from 22 autosomes (Table 1), 8 for each
chromosome, these STR markers were selected for their polymorphism
in the Chinese population and their physical locations which were
able to represent a given chromosome segment. Additional 6 STR
markers (indicated in (Table 2) were
chosen from the short arm of 19th chromosome to define
the borders of the cosegregating region. Primer sequences of these
markers were obtained from the CHLC Marker Maps [5] and TPMD Map
Display [6]. The NCBI Map Viewer [7] was used to determine the
marker positions. These markers were amplified by polymerase chain
reaction (PCR) based on the protocol reported by Walsh et al. [8]
with slight modification, shortly, in a 20 μl, including 10
mmol L–1 Tris-HCl, pH8.3, 50 mmol
L–1 KCl, 1.5 mmol L–1 MgCl2,
0.2 mmol L–1 of each dNTP, 1.5U
AmpliTaq® DNA polymerase, 15 pmol each primer, 1 μL
genomic DNA. The PCR cycles were performed as the following:
heating at 94 oC for 60 s (denature),
incubating at 60 °C for 60 s (anneal) and incubating at
72 oC for 60 s (extend) by the ‘step-cycle’
program. After 30 cycles, the samples were incubated for an
additional 30 min at 60 oC. PCR products were
analyzed by vertical electrophoresis polyacrylamide gels (PAGE) and
silver staining (figure
4).
Table 1 182 STR markers from autosomes used in this
study
|
Chrom.
|
Loci
|
|
1
|
D1S1646, D1S1676, D1S2134, D1S1631, D1S1677, D1S518, D1S2141,
D1S1656
|
|
2
|
D2S1780, D2S1346, D2S441, D2S1790, D2S436, D2S1334, D2S1353,
D2S434
|
|
3
|
D3S2432, D3S2409, D3S2406, D3S1358, D3S2459, D3S1744, D3S1763,
D3S2398
|
|
4
|
D4S2633, D4S2397, D4S2632, D4S1627, D4S3248, D4S1647, D4S2394,
D4S1652
|
|
5
|
D5S2488, D5S2848, D5S2506, D5S1457, D5S2500, D5S1505, D5S1480,
D5S1456
|
|
6
|
D6S1034, D6S1266, D6S1022, D6S1017, D6S1031, D6S1043, D6S1040,
D6S1027
|
|
7
|
D7S3056, D7S3048, D7S817, D7S1818, D7S2204, D7S2842, D7S2202,
D7S2208
|
|
8
|
D8S1458, D8S1140, D8S1469, D8S1130, D8S1113, D8S2324, D8S1132,
D8S1985
|
|
9
|
D9S288, D9S925, D9S1118, D9S161, D9S301, D9S922, D9S938, D9S926
|
|
10
|
D10S1415, D10S1430, D10S1423, D10S1214, D10S1221, D10S676,
D10S1239, D10S1213
|
|
11
|
D11S2362, D11S1999, D11S1977, D11S1978, D11S1983, D11S1367,
D11S2000, D11S4464
|
|
12
|
D12S391, D12S373, D12S1042, D12S1301, D12S1294, D12S1064, D12S395,
D12S1045
|
|
13
|
D13S787, D13S893, D13S1491, D13S325, D13S792, D13S317, D13S892,
D13S796
|
|
14
|
D14S742, D14S608, D14S750, D14S579, D14S745, D14S302, D14S617,
D14S1426
|
|
15
|
D15S817, D15S1232, 15S659, D15S648, D15S643, D15S653, D15S657,
D15S642
|
|
16
|
D16S768, D16S3391, D16S764, D16S753, D16S771, D16S752, D16S539,
D16S2621
|
|
17
|
D17S1308, D17S1298, D17S1288, D17S969, D17S1293, D17S1531,
D17S1290, D17S1301
|
|
18
|
D18S976, D18S843, D18S542, D18S847, D18S978, D18S51, D18S1357,
D18S844
|
|
19
|
D19S591, D19S583, D19S586, D19S1165, D19S253, D19S714, D19S593,
D19S1037, D19S434, D19S433, D19S1167, D19S400, D19S601, D19S589
|
|
20
|
D20S603, D20S604, D20S470, D20S477, D20S601, D20S85, D20S480,
D20S1082
|
|
21
|
D21S1432, D21S11, D21S1442, D21S2052, D21S1270, D21S1439, D21S1440,
D21S1446
|
|
22
|
GATA198B05, D22S686, D22S689, D22S683, D22S692, D22S1265, D22S691,
D22S1267
|
Table 2 14 STR markers from chromosome 19 used in this
study
|
Locus
|
Chrom. location
|
Fragment length
|
Alleles in this study
|
|
D19S591a
|
19p13.3
|
256-288bp
|
8, 9, 10, 11, 12
|
|
D19S583a
|
19p13.3
|
220-241bp
|
10, 11, 13, 14, 15
|
|
D19S586b
|
19p13.2
|
222-250bp
|
9, 11, 12, 13, 14, 15, 16
|
|
D19S1165a
|
19p13.2
|
140-164bp
|
10, 12, 13, 15, 16
|
|
D19S253a
|
19p13.12
|
209-241bp
|
7, 8, 13, 14, 15
|
|
D19S714b
|
19p13.1
|
225-253bp
|
9, 10, 14, 15, 16
|
|
D19S593a
|
19p13.1
|
256-288bp
|
22, 23, 24, 25
|
|
D19S1037a
|
19p12
|
117-141bp
|
18, 19, 20, 21, 22, 23
|
|
D19S434b
|
19p11
|
264-280bp
|
18, 19, 20, 21, 22
|
|
D19S433b
|
19q12
|
199-221bp
|
12, 13, 14, 15, 16
|
|
D19S400b
|
19q13.1
|
193-225bp
|
9, 10, 12, 13, 14
|
|
D19S1167b
|
19q13.2
|
340-376bp
|
31, 34, 35, 36, 37
|
|
D19S601b
|
19q13.41
|
204-232bp
|
18, 19, 20, 22
|
|
D19S589b
|
19q13.42
|
161-181bp
|
11, 12, 13, 15
|
aStanding for STR markers used in the first
screening.
bSTR markers used to define the borders of
the co-segregating region.
Nomenclature for allele of STR
According to the guideline recommended by the DNA Commission of the
International Society for Forensic Haemogenetics (ISFH) [9, 10],
every allele of STR locus was named by the repeat number of its
repetitive sequence. After purification with a E.Z.N.A.®
Cycle-Pure Kit (Omega Bio-tek), PCR products of 2 alleles from
every STR locus were directly sequenced for their repetitive
numbers on an Applied Biosystems 377 automatic sequencer (Applied
Biosystems). PCR products were syn-electrophoresed with molecular
weight standard Ø174/HaeIII ladder (Invitrogen, 10821-015), then
every allele was named by its repeat number.
Principle for linkage analysis
As FPH was demonstrated to be an autosomal dominantly inherited
disease, principles for judging linkage between its genotype and
phenotype are as follows: 1) If an allele or haplotype is present
in all affected individuals and not present in all unaffected
individuals, it is suggested to be linked to the pathogenic gene;
2) If an allele or haplotype is present in some, but not all,
affected individuals and not present in all unaffected individuals,
it is possible that this allele or haplotype links to the
pathogenic gene; 3) If an allele or haplotype is present randomly
in affected and unaffected individuals, it is excluded from linkage
to the pathogenic gene.
Results
Linkage analysis shows a short arm of chromosome 19
co-segregating with the disorder
A panel of 176 STR markers (table 1) of autosomes, were used for
the primary screening. Alleles of 17 subjects from the pedigree
were determined according to the principle of nomenclature for
allele of STR; then haplotypes or their recombinants were deduced
for each chromosome. Those STR haplotypes or recombinants present
in both the affected and unaffected individuals were ruled out. The
result shows the short arm of chromosome 19 harbors the FPH locus,
for the disease phenotype co-segregating with a STR haplotype of
19p, i.e. 19S586-19S714 (figure 1). Apparently,
I1 carries the FPH haplotype which is inherited by all
the other affected individuals in this family, not by the normal
ones.
A recombination between D19S714 and D19S593 indicates the FPH
locus residing in the chromosome 19p13.1-pter
In order to define the borders of the co-segregating region,
additional 6 STR markers from the short arm of chromosome 19 were
used. The proximal border of the critical region was defined by a
breakpoint of recombination, present in individual III5
between the markers D19S593 and D19S714 (figure 4). As there is no
recombination observed for the distal region from the breakpoint on
the haplotype, the distal border of the critical region was defined
to 19pter. This result indicates that the gene responsible for FPH
in this family is located within the region between 19p13.1 and
19pter.
Discussion
FPH is a rare inherited disease, there have been only 4 pedigrees
reported in the world up to now [1-4]. Although there are no whorls
and streaks as reported by Chernosky et al. [1] and no
hypopigmented macules as observed by Rebora and Parodi [2], the
patients included in this study show classical features of FPH,
i.e., hyperpigmented patches in the skin which were present in
early infancy and increased in size and number with age, and the
histological features that described for FPH as previous reports.
Because of the absence of hypopigmented lesion in our patients,
dyschromatosis symmetrica hereditaria [11] and dyschromatosis
universalis hereditaria [11], which are characterized by
hyperpigmented and hypopigmented macules on the skin of body, are
not considered. Since the hyperpigmented lesions in our patients
are flat, reticulate acropigmentation of Kitamura [12], which has
reticulate pigmentation that is slightly depressed below the skin
surface, can be excluded.
The pathogenesis of FPH is not understood to date. Since FPH
manifests disorders of pigmentation without association with any
other systemic disease, this feature makes FPH a possible model to
map the gene(s) involved in the process of pigmentation. Previous
studies, including this one, show FPH is a monogenic trait
inherited in an autosomal dominant pattern. However, there is no
study providing the linkage information for FPH locus until this
report. Family-based genome screening is applied as a strategy to
map FPH locus in our study. Samples of a 3-generation Chinese FPH
family were tested for STR markers to seek the chromosome region
co-segregating with the disease. With 182 autosomal STR markers,
the FPH locus is observed to link to the region covering D19S714
and D19S591 which are markers for 19p13.1-19pter. The genetic
distance of region in Marshfield is 45.48 cM and physical distance
in UCSC is 17.17Mb, harboring 628 defined genes.
It is interesting to note that the predisposing locus for
Peutz-Jeghers syndrome (PJS) was mapped to 19p13.3 [13, 14], which
is covered by the region which our study shows is where the FPH
locus is. PJS is characterized by the occurrence of hamartomatous
gastrointestinal polyps as well as mucocutaneous pigmentation. PJS
patients are also known to have an increased risk of developing
gastrointestinal and non-gastrointestinal malignancies. Germline
mutations in the LKB1 gene (official HUGO symbol, STK11,
serine/threonine protein kinase 11, MIM# 602216) at 19p13.3 were
shown to be associated with PJS. Although the possibility of the
involvement of other loci, working alone or in concert with the
LKB1 gene, cannot be ruled out, most (60-70%) patients with PJS
show germline mutations in the LKB1 gene (reviewed by Marignani
[16]). 145 different germline LKB1 mutations have been reported
[15, 16]. There is some evidence of the genotype-phenotype
correlations in PJS, but due to the complexity in both PJS
manifestations and LKB1 mutational types, observations need to be
confirmed.
FPH and PJS share the disorder of pigmentation, but differ in
the association with other systemic disorders. The fine mapping of
the FPH gene and comparative studies will be helpful to interpret
the pathogenesis of hyperpigmentation, as well as the
genotype-phenotype correlations in PJS. Although our study shows
the linkage of the FPH locus to human chromosome 19p13.1-pter, it
is obvious that more familial or/and sporadic FPH cases are
required for the further fine mapping.
Acknowledgements
We are grateful to the family members who participated in this
study. This study was supported by the Young Scientist Research
Funding from the Tongji Hospital.
References
1 Chernosky ME, Anderson DE, Chang JP, et al.
Familial progressive hyperpigmentation. Arch Derm 1971; 103:
581-91.
2 Rebora A, Parodi A. Universal inherited
melanodyschromatosis: a case of melanosis universalis hereditaria?
Arch Derm 1989; 125: 1442-3.
3 Debao L, Ting L. Familial progressive
hyperpigmentation: a family study in China. Brit J Derm 1991; 125:
607.
4 Luo Ting, Lin Shu-qing, Liu Ruo-ying, et al. Pedigree
analysis to a Chinese Han origin family with familial progressive
hyperpigmentation. Chin J Med Genet 1994; 11: 174-5; (in
Chinese).
5 The Cooperative Human Linkage Center. CHLC Marker Maps.
Available at: http://lpgws.nci.nih.gov/html-chlc/Chlc Marker Maps.
Html. Accessed 18 August 2005.
6 Taiwan Polymorphic Marker Database. TPMD Map Display.
Available at: http://tpmd.nhri.org.tw/php-bin/graphic.php?lang=en.
Accessed 18 August 2005.
7 National Center for Biotechnology Information. NCBI Map
Viewer. Available at:
http://www.ncbi.nlm.nih.gov/mapview/maps.cgi?taxid. Accessed 15
August 2005.
8 Walsh PS, Fildes NJ, Reynolds R. Sequence
analysis and characterization of stutter products at the
tetranucleotide repeat locus vWA. Nucleic Acids Res 1996; 24:
2807-12.
9 Bar W, Brinkmann B, Budowle B, et al. DNA
recommendations. Further report of the DNA Commission of the ISFH
regarding the use of short tandem repeat systems. International
Society for Forensic Haemogenetics. Int J Legal Med 1997; 110:
175-6.
10 DNA commission of the international society for forensic
haemogenetics report concerning further recommendations of the DNA
Commission of the ISFH regarding PCR-based polymorphisms in STR.
Int J Legal Med 1994; 107: 159.
11 Suenaga M. Genetical studies on skin diseases: VII.
Dyschromatosis universalis hereditaria in five generations. Tohoku
J Exp Med 1952; 55: 373-6.
12 Griffiths WA. Reticulate acropigmentation of Kitamura.
Br J Dermatol 1976; 95: 437-43.
13 Jenne DE, Reimann H, Nezu J, et al.
Peutz-Jeghers syndrome is caused by mutations in a novel serine
threonine kinase. Nat Genet 1998; 18: 38-43.
14 Hemminki A, Markie D, Tomlinson I, et al.
A serine/threonine kinase gene defective in Peutz-Jeghers syndrome.
Nature 1998; 391: 184-7.
15 Launonen V. Mutations in the human LKB1/STK11 gene. Hum
Mutat 2005; 26: 291-7.
16 Marignani PA. LKB1, the multitasking tumour suppressor
kinase. J Clin Pathol 2005; 58: 15-9.
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