Cutaneous mastocytosis in twins: multiple mastocytomas and urticaria pigmentosa in two pairs of monozygotic twins

We report two sets of monozygotic twins with cutaneous mastocytosis: one set with urticaria pigmentosa and the other set with multiple mastocytomas. This is the first report of multiple mastocytomas in twins to our knowledge.     

Analysis of c-kit exon 11 and exon 17 of urticaria pigmentosa that occurred in monozygotic twin sisters

Genomic DNA extracted from peripheral blood mononuclear cells of monozygotic twin patients with urticaria pigmentosa was investigated for mutations of proto-oncogene c-kit. Neither the patients nor their families had genomic mutations in exon 11 or exon 17 of c-kit. The patients did not have any systemic involvement or bone marrow abnormalities. There are indications that some genetic factors may participate in the pathogenesis of urticaria pigmentosa in monozygotic twins. In the present patients, factors other than genomic faults in exon 11 and exon 17 of c-kit may be responsible for the pathogenesis.     

One hundred twin pairs patch tested with primary irritants*

The cutaneous sensitivity to benzalkonium chloride, sodium lauryl sulphate and potash soap was determined in 54 monozygotic and 46 dizygotic twin pairs. Comparing the intra-pair reaction strength a higher degree of concordance was found among monozygotic than among dizygotic twins, and even more so when monozygotic twins were compared with matched controls.     

Psoriasis in monozygotic twins: variations in expression in individuals with identical genetic constitution

The variation in expression of psoriasis, in individuals with identical genetic constitutions, i.e. monozygotic twins, has been studied in a population-based sample of monozygotic twins in the Danish Twin Register. All verified and probable cases of psoriasis in twins, born between 1891 and 1930 inclusive, were ascertained. Results are presented of an examination of all members of index pairs in which both partners were alive. The zygosity determination was based in 94% of the pairs on very extensive serological examinations. Thirty-two monozygotic pairs were found to include at least one partner with unquestionable psoriasis (18 concordant, 14 discordant). The analyses give firm evidence of the contribution of genetic factors to the manifestation, age at onset, clinical type, course, and severity of psoriasis. A close association between psoriasis and HLA-B 13 an B 17 was found in both discordant and concordant pairs. No difference was found between partners from discordant MZ-pairs with regard to infections or marked 'stress' conditions.     

Hand eczema in nickel-sensitive female twins. Genetic predisposition and environmental factors

The Danish Twin Register represents a population-based twin sample where the twins enter the Register independently of disease.
All female twins born between 1906–30 and available in the Register in January 1978 were sent a questionnaire concerning possible nickel sensitivity. Among 74ft pairs living in the eastern part of Denmark, 129 twins from 115 pairs had a possible nickel allergy. Through a subsequent personal visit and, in most eases, patch testing, 34 monozygotic probands from 30 pairs and 45 dizygotic probands from 41 pairs were considered to have a verified nickel sensitivity and fulfilled the restriction criteria for the present study.
The prevalence of present or previous hand eczema in both the monozygotic and the dizygotic probands was 41% (95% confidence limits: 30–52%). In 15 of the 32 with hand eczema, this was in the form of a relapsing pompholyx.
Analysis of the monozygotic pairs showed that the risk of developing hand eczema in the co-twins seemed independent of whether the proband had nickel allergy and hand eczema or nickel allergy alone. Furthermore, it was found that the number of affected co-twins was comparable with the background population. Thus the association between nickel allergy and hand eczema is probably not due to a common genetic predisposition. Environmental factors seem decisive.     

Identical twins with primary cutaneous melanoma presenting at the same time and location

Thus far there have been very few cases that document such a rarity as the same cancer occurring in monozygotic twins, at the same time, in the same location. We report this extraordinary phenomenon in our patients, 71-year-old identical female twins, presenting with melanoma at the same time (within 10 days of each other) and location (the right calf).     

Chondrodermatitis nodularis chronica helicis in monozygotic twins

Chondrodermatitis nodularis chronica helicis (CNCH) is a benign inflammatory nodule of the helix. Patients report severe tenderness upon pressure. Commonly seen in middle-aged men, there are no reports of this disease in twins. We report middle-aged male monozygotic twins who simultaneously developed CNCH. This suggests, but does not prove, the possibility of a hereditary factor in the pathogenesis of CNCH.     

Monozygotic twins with atrophia maculosa varioliformis cutis

Atrophia maculosa varioliformis cutis (AMVC) is a sporadic or inherited childhood disorder, signified by the occurrence of pitted scars, usually over the face. We report two cases of AMVC occurring in monozygotic twins.     

Psoriasis in an unselected series of twins

The relative importance of genetic factors in the origin, age at onset, clinical type, course, and severity of psoriasis was evaluated on the basis of an unbiased sample of twins, ie, the Danish Twin Register, which covers the total population of twins born in Denmark. All verified and probable cases of psoriasis in twins, born 1891 through 1920, were ascertained. Results are presented of an examination of all members of index pairs in which both partners were alive on a certain date. Fourteen monozygotic and 22 dizygotic, like-sexed pairs were found to include at least one partner with unquestionable psoriasis. Zygosity determination was mainly based on extensive serological examinations. The analyses show that the manifestation of psoriasis depends almost exclusively on the presence of the specific genotype. The age at onset, clinical type, course, and severity are also mainly determined by the genetic constitution. Association with certain HLA antigens of the B series has been confirmed, but the fact that many of the twins (including several of the concordant monozygotic pairs) possess neither of these antigens shows the corresponding genes to be important, but not decisive, elements in the predisposition. We conclude that psoriasis is a genetically determined disorder that may, to a limited extent, be modified by environmental influences.     

Discordant expression of tuberous sclerosis in monozygotic twins

A set of 20-year-old female Japanese twins, most probably monozygotic, had clinical evidence of tuberous sclerosis (TS). They were discordant for symptoms. One of the twins exhibited facial red-brown papules (adenoma sebaceum), a dorsal shagreen patch, intracerebral calcifications, angiomyolipoma in the right kidney, and hypopigmented macules; the other had only a few hypopigmented macules. Modification of TS gene expression by the effects of environmental (extrinsic) factors is suggested.     

Dubowitz-Syndrom und atopisches Ekzem

Autosomal recessive inheritance, intrauterine growth retardation, short stature, microcephaly, distinct facial dysmorphism, psychomotoric retardation, and often uncharacterized eczematous skin lesions distinguish the rare Dubowitz syndrome. Here a pair of monozygotic twins with Dubowitz syndrome and clear-cut atopic eczema is presented.     

Juvenile generalized pustular psoriasis in a pair of monozygotic twins presenting strikingly similar clinical courses.

We describe an exceptionally rare case of juvenile generalized pustular psoriasis noted in monozygotic twins who, after developing the disease on the same day (the 48th day after birth) continued to show strikingly similar clinical features of generalized pustular psoriasis for 7 years. Not even therapeutic intervention by tonsillectomy performed at age 4 years on one of the twins, which was expected to have some beneficial effect, could decrease the number of attacks or pustulation compared with the counterpart.     

Solitary congenital self-healing reticulohistiocytosis in monozygotic twins

We report monozygotic twins with congenital self-healing reticulohistiocytosis, whose lesions initially presented as hemorrhagic bullae at birth with rapid progression into crusted papules the following day. Physical examination disclosed crusted papules on the right side of the neck of twin 1 and a similar solitary lesion on the lateral side of the right thumb of twin 2. Excisional biopsy specimen findings of the neck and thumb lesions were consistent with Langerhans cell histiocytosis, which was further confirmed by positive CD1a staining. The lesions resolved completely by 2 months with no evidence of recurrence or systemic involvement. Congenital self-healing reticulohistiocytosis is a rare, self-limited form of Langerhans cell histiocytosis. Although familial clustering in Langerhans cell histiocytosis was previously reported, to the best of our knowledge there is no report suggesting familial clustering in congenital self-healing reticulohistiocytosis. Our patients are interesting in terms of raising the question of whether the presence of congenital self-healing reticulohistiocytosis in monozygotic twins is implicative of a genetic role in its pathogenesis.     

The development of lichen sclerosus et atrophicus in monozygotic twin girls

The development of vulval lichen sclerosus et atrophicus in monozygotic twins is described. This is the first report of the occurrence of lichen sclerosus et atrophicus in two genetically identical individuals, and is considered to provide further evidence that inherited factors are of relevance in the aetiology of this disorder.     

Juvenile xanthogranuloma in monozygotic twins

Juvenile xanthogranuloma is usually a benign condition mainly seen in infants and children. It frequently presents as asymptomatic discrete papules on the head, trunk, and limbs. Extracutaneous manifestations, most commonly ocular, are rare but may be associated with significant morbidity. The etiology of juvenile xanthogranuloma is uncertain, although the occurrence in monozygotic twins may suggest genetic predisposition.     

Psoriasis occuring in young monozygotic twins

Psoriasis occuring in monozygotic twins is reported. Although these patients had a different living environment since birth the similarity in psoriatic pattern and its time of onset suggested the strong influence of genetic factors. However the major histocompatibility antigens A2, A11, Bw(16), found in these patients were not those, which have been reported to be significantly increased among Japanese psoriatics.     

Langerhans cell histiocytosis in monozygotic twins

Langerhans cells histiocytosis, one of a group of histiocytosis syndromes characterized by Langerhans cell infiltration, has many clinical manifestations. In the past 30 years, numerous cases of presumed Letterer-Siwe disease, the acute multiorgan variant, have been reported in twins and siblings. Only recently has the Histiocyte Society established a criterion for a "definitive diagnosis" of Langerhans cell histiocytosis--the presence of Birbeck granules within the cells of the histiocytic infiltrate. We report the fatal outcome of Langerhans cell histiocytosis in monozygotic twin infants. There is no satisfactory explanation why Langerhans cell histiocytosis occurs concurrently in twins. We suggest that cytokines may provide an endogenous signal that triggers the pathologic proliferation of Langerhans cells.     

Familial progressive hypermelanosis in Indian monozygotic twins

Familial hyperpigmentation, or melanosis universalis hereditaria, is a rare hyperpigmentary disorder with onset in infancy. Here, we describe monozygotic twins with similar pattern of progressive hyperpigmentation with onset in early neonatal period without any family history. Histopathological examination showed increased melanin throughout the epidermis. Although hereditary defects may influence melanogenesis resulting in a pigmentary anomaly, the pathogenesis of hyperpigmentation in this case remains unclear.     

Linear porokeratosis of Mibelli in monozygotic twin girls

Two monozygotic female twins with linear porokeratosis of Mibelli are described. One had only minimal lesions of the right elbow. The other had a linear lesion of the right arm following Blaschko's lines. Monozygotism was established using DNA fingerprinting. A single-gene defect of variable expressivity involving the clonal development of epidermal cutaneous cells according to the lines of cutaneous embryogenesis is suspected. Dithranol and carbon dioxide laser treatment are discussed.     

The influence of genetics and environmental factors in the pathogenesis of acne: a twin study of acne in women

Acne is common and often leads to significant psychologic and physical morbidity. From clinical experience, acne appears to run in families; however, very few studies have investigated the genetic basis of this very common skin disease. A large twin study based on 458 pairs of monozygotic and 1099 pairs of dizygotic twins, all women with a mean age of 46 y was performed to investigate the relative contribution of genetic and environmental factors on the liability to acne. In addition, potential risk factors were assessed in twins with and without acne in a nested cross-sectional design. Fourteen percent of the twins reported a history of acne. Genetic modeling using acne scores showed that 81% (95% confidence interval 73-87%) of the variance of the disease was attributable to additive genetic effects. The remaining 19% was attributed to unique (i.e., unshared) environmental factors. Of the potential risk factors tested in 400 acne twins and 2414 unaffected twins, only apolipoprotein A1 serum levels were significantly lower in acne twins even after adjusting for age and weight. Family history of acne was also significantly associated with an increased risk. No significant differences were found between acne twins and nonacne twins for weight, body mass index, height, birth weight, hair thinning, reproductive factors as well as cholesterol, triglycerides, high-density lipoprotein, and glucose levels. The lower serum levels of apolipoprotein A1 in acne twins were also confirmed when analyzing acne discordant twin pairs. The evidence of a major genetic influence on acne should stimulate the search for potential genes that may lead to new therapeutic approaches.