RESEARCH LETTERS
melanocytic naevi are common in the general population and
are often located on the face. They are usually raised, and
therefore easy to identify. These naevi are generally
characterised by a proliferation of dermal melanocytes and do
not have dysplastic features.1
A review of published work revealed one case of
similar non-pigmented melanocytic lesions. Knoell and
colleagues2 describe a 31-year-old white woman presenting
with non-pigmented DMN. Although the clinical appearance
and microscopic findings were similar to those seen in our
patients, no association with malignant melanoma was made
in this case. Furthermore, Grosshans and colleagues3 described
a 28-year-old woman who presented with white macules on
sun-exposed areas, which resembled the lesions seen in our
patients. However, microscopic investigation showed a
decrease in epidermal pigmentation without melanocytic
hyperplasia. These lesions were interpreted as hypomelanotic
actinic lentigo.
White DMN are clinically inconspicuous and do not suggest
a melanocytic process. Clinical differential diagnosis of these
white DMN include idiopathic guttate, flat warts,
hypomelanosis, anetoderma, pityriasis alba, hypopigmented
mycosis fungoides, vitiligo, post-inflammatory hypopigmentation, lichen sclerosus et atrophicus, superficial
morphea, and leprosy. The silvery shine seen under tangential
light is a clue to the clinical diagnosis of white DMN.
That two of our patients had histories of malignant
melanoma, and that the other had two malignant melanomas
is relevant; this patient’s malignant melanomas were also nonpigmented. Histologically, the lack of melanin in the overlying
epidermis and in the adjacent naevus cells is compatible with a
low degree of melanin synthesis in the naevus cells.
Immunohistochemical staining for HMB-45 suggested the
presence of melanosomal proteins in a few melanocytic cells.
We did not find an increase in Langerhans cells, which would
have suggested vitiligo-like changes. Although the clinical
appearance of the white DMN is very different from that of
pigmented DMN, histological findings are quite similar.4
To rule out white DMN, we suggest taking biopsy samples
from patients who present with white to pale-red macules with
accentuated skin markings, which cannot be clearly classified.
Treatment of white DMN should be similar to that of their
pigmented counterpart.5 At present, the frequency of white
DMN is unknown, and in many cases the lesions may remain
unnoticed because of their inconspicuous clinical appearance.
On the basis of only three patients it is premature to use white
DMN to suggest the presence of malignant melanoma, and
therefore, further investigation is required.
Contributors
I Zalaudek wrote the report. R Hofmann-Wellenhof did clinical diagnosis
and documentation. L Cerroni did histological diagnosis. H Kerl reviewed
the final version of the report.
Conflict of interest statement
None declared.
1
2
3
4
5
Ackerman AB, Magana-Garcia M. Naming acquired melanocytic nevi:
Unna’s, Miescher’s, Spitz’s, Clark’s. Am J Dermatopathol 1990; 12:
193–209.
Knoell KA, Hendrix JD Jr, Patterson JW, McHargue CA, Wilson BB,
Greer KE. Nonpigmented dysplastic melanocytic nevi. Arch Dermatol
1997; 133: 992–94.
Grosshans E, Sengel D, Heid E. La lentiginose blanche. Ann Dermatol
Venereol 1994; 121: 7–10.
Ackerman AB, Cerroni L, Kerl H. Pitfalls in histopathologic diagnosis of
malignant melanoma. Philadelphia: Lea & Febiger, 1994.
NIH Consensus Development Panel on Early melanoma. Diagnosis and
treatment of early melanoma. JAMA 1992; 268: 1314–19.
Department of Dermatology, University of Graz, A-8036 Graz, Austria
(I Zalaudek MD, R Hofmann-Wellenhof MD, L Cerroni MD, H Kerl MD)
Correspondence to: Dr Iris Zalaudek
(e-mail: [email protected])
2000
Mapping of the wet/dry earwax
locus to the pericentromeric region
of chromosome 16
Hiroaki Tomita, Koki Yamada, Mohsen Ghadami, Takako Ogura,
Yoko Yanai, Katsumi Nakatomi, Miyuki Sadamatsu, Akira Masui,
Nobumasa Kato, Norio Niikawa
Human earwax is a one-gene trait comprising two phenotypically
distinct forms—wet and dry. This trait is attributed to secretory
products of the ceruminous apocrine glands, and frequencies of
phenotypes vary between ethnic groups. We did linkage analysis
of eight Japanese families segregating earwax dimorphism. We
assigned the earwax locus within a ~7·42-cM region between the
loci D16S3093 and D16S3080 on chromosome 16p11.216q12.1, with a maximum two-point LOD score of 11·15
(␪=0·00) at the locus D16S3044. Identification of the earwax
locus could contribute to further anthropogenetic studies and
physiological and pathological understanding of the apocrinegland development.
Lancet 2002; 359: 2000–02
The type of earwax (cerumen) in people is coded for by one
gene, and has two phenotypically distinct forms: wet and dry
(OMIM 117800). Wet cerumen is light-brown or dark-brown
and sticky, whereas dry cerumen is grey or tan and brittle.
Since the phenotype of homozygotes for the wet type (WW) is
indistinguishable from that of heterozygotes (Ww), the wet
phenotype is dominant.1
Frequencies of wet and dry types of cerumen vary between
ethnic groups. Wet earwax is frequent in whites and African
Americans, whereas dry earwax is common among Asian
people and native Americans, and is of intermediate frequency
in populations in eastern Europe, the Middle East, the Pacific
islands, and South Africa.1,2
The difference in nature of wet and dry cerumen is
attributed to secretory products of ceruminous glands.
Histological studies have shown abundant lipid droplets and
pigment granules in the cytoplasm of secretory cells
in individuals with wet cerumen, whereas in individuals with
dry cerumen, these cytoplasmic components are scarce.1
The ceruminous gland is an apocrine gland, as are axillary
and breast glands. In individuals with dry cerumen, the axillary
apocrine gland is usually much less developed than in those
with wet cerumen, and therefore the dry type is associated with
less axillary odour.1 Petrakis3 has shown an association between
earwax type and breast cancer, which suggests that there is a
genetic factor affecting secretion from ceruminous and breast
glands. Thus, a gene coding for earwax type could control
development of apocrine glands and the nature of their
secretory products.
We did linkage analysis of a woman with paroxysmal
kinesigenic choreoathetosis, who told us that six people in her
family also had choreoathetosis, and that those with the disease
had wet earwax. Her claim made us think about a possible
co-segregation of this disease with the earwax trait locus. Thus
Genetic
markers
Recombination fractions (␪)
D16S403
D16S3093
D16S3105
D16S3044
D16S517
D16S3080
D16S411
D16S3117
D16S3136
D16S416
D16S415
–INF
–6·63 1·59 2·55
–INF
–6·16 3·12 3·95
4·70
4·70 4·68 4·35
11·15 11·14 10·29 9·24
4·37
4·36 3·88 3·37
–INF
3·63 7·80 7·59
–INF
1·52 4·37 4·32
3·24
3·25 3·18 2·92
–INF
–2·23 4·02 4·48
2·12
2·14 2·40 2·28
–INF –14·33 0·04 1·75
0
0·001 0·05 0·1
0·15
0·2
0·3
0·4
2·75
3·99
3·89
8·07
2·84
6·89
3·97
2·57
4·33
2·04
2·30
2·59
3·68
3·34
6·80
2·31
5·96
3·49
2·17
3·91
1·73
2·34
1·74
2·52
2·14
4·07
1·26
3·75
2·33
1·27
2·61
1·01
1·71
0·65
1·07
0·96
1·47
0·38
1·50
1·08
0·40
1·13
0·32
0·72
INF=infinity.
Two-point LOD scores at various recombination fractions
THE LANCET • Vol 359 • June 8, 2002 • www.thelancet.com
For personal use. Only reproduce with permission from The Lancet Publishing Group.
RESEARCH LETTERS
(6)
(2)
(5)
(2)
(2)
(6)
(4)
(4)
(4)
(3)
(1)
2
1
6
2
5
2
2
6
4
4
4
3
1
3
4
2
2
3
7
3
2
4
3
3
3
(7)
(5)
(3)
(5)
(3)
(5)
(5)
(4)
(4)
(3)
(3)
(3) (4)
(4) (1)
(2) (3)
(2) (1)
(3) (3)
(7) (4)
(3) (9)
(2) (2)
(4) (4)
(3) (2)
(3) (4)
2
6
2
4
2
3
6
7
4
1
3
3
3
3
4
2
2
3
7
3
2
4
3
4
6
2
5
2
2
6
4
4
4
3
1
4
4
1
3
1
3
4
9
2
4
2
4
5
1
3
5
3
6
9
1
4
3
4
1
6
2
4
2
3
6
7
4
1
3
3
1
6
2
4
2
3
6
7
4
1
3
3
7
5
3
3
3
6
3
2
2
3
3
5
1
3
5
3
5
5
4
4
3
3
2
2
2
4
3
6
9
4
4
3
4
2
2
2
4
3
6
9
4
4
3
4
6
7
1
3
5
3
6
9
1
4
3
4
7
1
3
3
1
7
5
4
4
3
3
7
7
5
3
5
3
5
5
4
4
3
3
8
7
1
3
3
1
7
5
4
4
3
3
5
1
3
5
3
6
9
1
4
3
4
1
2
2
2
4
3
6
9
4
4
3
4
7
5
3
5
3
5
5
4
4
3
3
7
2
3
3
3
6
3
2
2
3
3
1
7
2
2
3
1
7
8
1
2
3
3
7
5
3
3
2
2
3
2
4
3
6
Dry type
6
4
4
5
3
6
3
2
1
3
4
6
4
4
3
1
7
3
4
4
1
6
2
7
5
3
3
2
2
3
2
4
3
6
6
1
3
3
3
6
5
2
4
3
3
6
4
4
5
3
6
3
2
1
3
4
7
2
4
5
3
6
3
2
1
3
4
3
6
4
4
5
3
6
3
2
1
3
4
5
2
3
3
2
2
3
2
3
3
3
2
7
2
2
3
1
7
8
1
2
3
3
2
(6) (5)
(1) (2)
(3) (3)
(3) (3)
(3) (2)
(6) (2)
(5) (3)
(2) (2)
(4) (3)
(3) (3)
(3) (3)
1
2
6
1
3
3
1
7
5
4
4
3
3
Family 2
Genetic
Distance
Markers
(cM)
D16S403
8.4
6.2 D16S3093
D16S3105
0.0 D16S3044
1.2 D16S517
D16S3080
0.0 D16S411
2.4 D16S3117
3.0 D16S3136
2.5 D16S416
D16S415
3
3
4
2
2
3
7
3
2
4
3
4
7
5
3
5
3
2
5
2
4
3
3
4
(7) (2)
(1) (2)
(3) (2)
(3) (4)
(1) (3)
(7) (6)
(5) (9)
(4) (4)
(4) (4)
(3) (3)
(3) (4)
5
2
7
2
3
3
3
6
3
2
2
3
3
7
1
3
3
1
7
5
4
4
3
3
(5)
(1)
(3)
(5)
(3)
(6)
(9)
(1)
(4)
(3)
(4)
16q12.1
1
(6)
(2)
(4)
(2)
(3)
(6)
(7)
(4)
(1)
(3)
(3)
16p11.2
Family 1
6
4
4
3
1
7
3
4
4
1
6
4
6
1
3
3
3
6
5
2
4
3
3
7
2
4
5
3
6
3
2
1
3
4
5
(7) (?)
(5) (?)
(3) (?)
(3) (?)
(3) (?)
(2) (?)
(3) (?)
(1) (?)
(4) (?)
(2) (?)
(3) (?)
4
3
7
2
2
3
1
7
8
1
2
3
3
Wet type
6
1
3
3
3
6
5
2
4
3
3
6
1
3
3
3
6
5
2
4
3
3
7
5
3
3
3
2
3
1
4
2
3
Type unknown
(n) Haplotype deduced from offspring
Recombination
n
Possible recombination
Common haplotype for wet type
Representative pedigrees segregating the wet/dry earwax dimorphism
?=unknown. Genetic distances were estimated on the basis of Marshfield Medical Research Foundation genetic map (http://research.marshfieldclinic.org).
we did linkage analysis of eight Japanese families segregating
the cerumen dimorphism.4,5
92 people from eight Japanese families (figure), who
segregated the dimorphism, participated in the study (a more
detailed figure is available at http://image.thelancet.com/extras/
01let7280webfigure.pdf); we obtained informed consent from
all participants. We interviewed participants about their earwax
type, and if obscure, type was confirmed by observation of
earwax scratched by a swab. On the basis of co-segregation of
earwax type and paroxysmal kinesigenic choreoathetosis, which
maps to chromosome 16 pericentromeric region,4,5 we chose 11
microsatellite markers that cover this region (table) before
starting whole-genome analysis. We amplified DNA from
participants by PCR with Cy5-labelled primer sets. We did
electrophoresis of PCR products in an automated DNA-
THE LANCET • Vol 359 • June 8, 2002 • www.thelancet.com
sequencer, and analysed resulting data with Fragment
Manager (version 1.2; Pharmacia Biotech, Uppsala, Sweden)
to establish allelotypes, as described elsewhere.4 We calculated
LOD scores4 on the basis of the assumptions that wet earwax is
inherited in an autosomal dominant manner with complete
penetrance, and that allele frequencies of W and w in the
general Japanese population are 0·085 and 0·915, respectively.1
Results of two-point linkage analysis gave a maximum LOD
score of 11·15 (␪=0·00, penetrance p=1·0) at the locus
D16S3044 (table). Results of haplotype analysis defined the
locus within a ~7·42-cM region between markers D16S3093
and D16S3080 (figure). With these data, we assigned the
earwax locus to chromosome 16p11.2-16q12.1.
The region to which we mapped the earwax locus is
included in the region associated with paroxysmal kinesigenic
2001
For personal use. Only reproduce with permission from The Lancet Publishing Group.
RESEARCH LETTERS
choreoathetosis, therefore the two loci should be close to each
other.4 Identification of the earwax locus could contribute to
further anthropogenetic studies and to physiological and
pathological understanding of apocrine-gland development.
Contributors
H Tomita designed and organised the study, obtained phenotypic
information and DNA samples from family 1, did genotyping and linkage
analysis of all the families, and wrote the report. K Yamada, M Ghadami,
T Ogura, and Y Yanai obtained phenotypic information and DNA samples
from one of the families, and did genotyping of this family. K Nakatomi,
M Sadamatsu, A Masiu, and N Kato obtained phenotypic information and
DNA samples from one of the families. N Niikawa organised and supervised
the study, obtained phenotypic information and DNA samples from one of
the families, and wrote the report.
Conflict of interest statement
None declared.
Acknowledgments
The project was funded by Core Research for Evolutional Science and
Technology, Japan Science and Technology Corporation. The sponsor of the
study had no role in study design, data collection, data analysis, data
interpretation, or writing of the report.
1
2
3
4
5
Matsunaga E. The dimorphism in human normal cerumen.
Ann Hum Genet 1962; 25: 273–86.
Ibraimov AI. Cerumen phenotypes in certain populations of Eurasia and
Africa. Am J Phys Anthropol 1991; 84: 209–11.
Petrakis NL. Physiologic, biochemical, and cytologic aspects of nipple
aspirate fluid. Breast Cancer Res Treat 1986; 8: 7–19.
Tomita H, Nagamitsu S, Wakui K, et al. Paroxysmal kinesigenic
choreoathetosis locus maps to chromosome 16p11·2-q12·1.
Am J Hum Genet 1999; 65: 1688–97.
Sadamatsu M, Masui A, Sakai T, Kunugi H, Nanko S, Kato N. Familial
paroxysmal kinesigenic choreoathetosis: an electrophysiologic and
genotypic analysis. Epilepsia 1999; 40: 942–49.
Department of Human Genetics, Nagasaki University School of
Medicine, Nagasaki, and Core Research for Evolutional Science and
Technology, Japan Science and Technology Corporation, Kawaguchi,
Japan (H Tomita MD, K Yamada MD, M Ghadami MD, T Ogura, Y Yanai,
N Niikawa MD); Second Department of Internal Medicine, Nagasaki
University School of Medicine, Nagasaki (K Nakatomi MD); Health
Service Center, University of Tokyo, Tokyo (M Sadamatsu MD);
Department of Psychiatry, Shiga University of Medical Science, Otsu
(A Masui MD); and Department of Neuropsychiatry, Faculty of Medicine,
University of Tokyo, Tokyo (N Kato MD)
Correspondence to: Dr Hiroaki Tomita, Department of Psychiatry and
Human Behaviour, University of California Irvine, D346 MED SCI I,
CA 92697-1675, USA
(e-mail: [email protected])
An epidemic Burkholderia cepacia
complex strain identified in soil
John J LiPuma, Theodore Spilker, Tom Coenye, Carlos F Gonzalez
Life threatening infection with species of the Burkholderia
cepacia complex frequently occurs as a result of cross infection
among individuals with cystic fibrosis. Stringent infection control
measures have decreased but not eliminated such infection in
this vulnerable population, implying that non-patient reservoirs
contribute to ongoing acquisition. However, strains common to
both the natural environment and patients with cystic fibrosis
have not yet been described. By use of various genotyping
methods, we have identified from agricultural soil the B cepacia
genomovar III strain that is most frequently recovered from cystic
fibrosis patients in the mid-Atlantic region of the USA. This finding
indicates that human pathogenic strains are not necessarily
distinct from environmental strains, and might help explain
ongoing human acquisition despite strict infection control
measures.
Lancet 2002; 359: 2002–03
Species of the Burkholderia cepacia complex have long been
recognised as important pathogens in people with cystic
fibrosis, in whom respiratory tract infection is often refractory
to antimicrobial therapy and associated with life threatening
2002
decline in pulmonary function. Infection in cystic fibrosis is
commonly linked to interpatient spread of specific epidemic
clones. Indeed, harsh infection control policies in cystic fibrosis
centres have decreased, but not entirely eliminated, new
acquisition of B cepacia complex. More recently, these species
have also been recognised as opportunistic pathogens capable
of causing nosocomial infection among debilitated patients
who do not have cystic fibrosis.1 In these instances the source
of infection is frequently not known.
At the same time that optimal infection control measures
have been sought to prevent human infection due to B cepacia
complex, these species have also attracted considerable
attention for their potential use both in the biocontrol of plant
disease and the bioremediation of recalcitrant environmental
xenobiotics.2 Some B cepacia complex strains have the capacity
to degrade pollutants including organophosphorous insecticides, polychlorinated biphenyls (PCBs), and chlorinated
ethenes such as trichloroethylene (TCE)—one of the world’s
most widespread ground water contaminants. This capacity
could be exploited in environmental clean-up programmes.
Other strains may be used as biopesticides to antagonise soilborne fungi such as Pythium spp and Fusarium spp, phytopathogens with wide host range, worldwide distribution, and
substantial economic impact.
The notion that human pathogenic and environmental
strains of B cepacia complex are clearly distinguishable has
raised hopes that naturally occurring strains could be
developed for commercial use. In fact, strains common to both
patients with cystic fibrosis and the natural environment have
been sought but none have yet been described. In an ongoing
study we have used several bacterial genotyping methods to
assess isolates recovered from patients with cystic fibrosis and
environmental sources in order to understand better the potential reservoirs of human infection due to B cepacia complex.
We analysed 175 B cepacia complex isolates recovered
during two consecutive growing seasons (1999 and 2000) from
organic soils in four agricultural fields (from two counties
located about 200 miles apart in New York State) that had
been planted with onions for several years. Species determination using both recA- and 16S rDNA-targeted PCR assays
identified 38 of these as genomovar III, the species most frequently recovered from sputum culture of patients with cystic
fibrosis.3 Genotyping analyses using repetitive extragenic
palindromic PCR (rep-PCR) and randomly amplified polymorphic DNA (RAPD) typing showed that several of these
genomovar III isolates were the same strain type. Computerassisted analyses of rep-PCR and RAPD profiles, using
UPMGA based clustering and a 0·8 similarity coefficient
cutoff,4 indicated that this strain type was the same as PHDC,
the genomovar III strain recovered from nearly all cystic
fibrosis patients who were infected with B cepacia complex in
large treatment centres in the mid-Atlantic region of the US.5
PHDC contains neither BCESM nor cblA markers, both of
which are features of ET12, the genomovar III strain that
predominates among infected cystic fibrosis patients in
Canada and the UK.
To further assess clonality we examined recA and flagellin
(fliC) genes, loci that have been used previously in phylogenetic
assessment and strain typing of B cepacia complex species.
Among a subset of eight PHDC soil isolates and ten PHDC
isolates from sputum culture taken from patients with cystic
fibrosis, the mean recA DNA sequence identity was 99·1%,
and all had identical fliC RFLP profiles after digestion with
each of five restriction enzymes (AluI, DdeI, HaeIII, MspI,
RsaI). By contrast, recA DNA sequences of 22 other
genomovar III isolates from unrelated cystic fibrosis patients or
soil sources exhibited 93·9% to 98·1% identity to the recA
sequence of PHDC strain AU1107, and 19 different fliC
RFLP profiles. Although genomic macrorestriction analysis by
THE LANCET • Vol 359 • June 8, 2002 • www.thelancet.com
For personal use. Only reproduce with permission from The Lancet Publishing Group.