Dyskeratosis congenita: a literature review

Dyskeratosis congenita is a rare hereditary disease that occurs predominantly in males and manifests clinically as the classic triad of reticulate hyperpigmentation, nail dystrophy and leukoplakia. It increases the risk of malignancy and other potentially lethal complications such as bone marrow failure, lung and liver diseases. Mutations in 19 genes are associated with dyskeratosis congenita, and a fifth of the pathogenic mutations are found in DKC1, the gene coding for dyskerin. This review aims to address the clinical and genetic aspects of the disease.     

Cytogenetic abnormalities in dyskeratosis congenita—report of five cases

Five patients with dyskeratosis congenita arc described. The cytogenetic studies showed varying frequencies of chromosomal abnormalities which included gaps, chromatid breaks and pulverizations, ranging from 4 to 22%. These findings suggest that chromosomal breakage may be of fundamental importance in the etiology of dyskeratosis congenita and it could represent a genetic marker for the disease.     

Hoyeraal–Hreidarsson Syndrome: An Extremely Rare Dyskeratosis Congenita Phenotype

Hoyeraal–Hreidarsson syndrome is a rare telomere biology disorder that is recognized as a severe variant of dyskeratosis congenita. We present a Libyan boy with hematologic and neurologic abnormalities with typical dermatologic manifestations of dyskeratosis congenita. Death usually occurs before the age of 4 years as a result of pancytopenia or malignant transformation of mucocutaneous lesions. The boy presented survived longer than 5 years. Early recognition and appropriate genetic counseling are crucial because of the high mortality of this genetic disorder.     

Dyskeratosis congenita associated with three malignancies

Dyskeratosis congenita is a rare inheritable disorder characterized by abnormalities of the skin, nails and oral mucosa. Aplastic anaemia resulting from bone marrow hypoplasia is a frequent cause of death. Squamous cell carcinoma developing from leukoplakia and visceral malignancies are other complications of the disease. We report here a case of dyskeratosis congenita in a man who developed three neoplasias of different systems over a period of many years. Squamous cell carcinoma and gastric adenocarcinoma manifested 17 years after the man was diagnosed with Hodgkin's disease.     

Identification of a novel mutation and a de novo mutation in DKC1 in two Chinese pedigrees with Dyskeratosis congenita

Dyskeratosis congenita (DKC) is a rare and fatal congenital syndrome characterized by the triad of reticular skin pigmentation, nail dystrophy and mucosal leukoplakia, and the predisposition to bone marrow failure and malignancies. Mutations in DKC1 gene encoding dyskerin are responsible for the X-linked dyskeratosis congenita. Here we report mutation analysis of two Chinese pedigrees with dyskeratosis congenita. The 15 coding exons of DKC1 and their flanking regions were amplified from genomic DNA by PCR. DNA sequencing and restriction endonuclease digestion were used for mutation detection. Transition mutation of 1226C-->T (P409L) found in the first pedigree is a novel mutation. In the second pedigree, the proband's mother phenotypically normal carried a de novo transition mutation of 1058C-->T (A353 V) in one allele, and transmitted the mutant allele to her two sons who had typical manifestations of dyskeratosis congenita.     

Dyskeratosis Congenita Associated with Elevated Fetal Hemoglobin, X-Linked Ocular Albinism, and Juvenile-Onset Diabetes Mellitus

An 11-year-old boy had dyskeratosis congenita, elevated fetal hemoglobin level, X-linked ocular albinism, and juvenile-onset diabetes mellitus. A review of the international literature revealed that elevated fetal hemoglobin has been noted in 15 reported cases of dyskeratosis congenita. It is a previously unrecognized, commonly associated finding in dyskeratosis congenita that may provide insight into the location and function of the gene for dyskeratosis congenita.     

Dyskeratosis congenita: delay in diagnosis and successful treatment of pancytopenia by bone marrow transplantation

Dyskeratosis congenita is an inherited disorder characterized by nail dystrophy, skin pigmentary changes, mucosal leukoplakia, pancytopenia and an increased incidence of malignancy. Because of a widely held view that the outcome of bone marrow transplantation in dyskeratosis congenita is poor, this treatment option is sometimes not considered when pancytopenia develops. We present a child currently doing well 3 years after bone marrow transplantation, and review the literature.     

Dyskeratosis congenita in an adolescent girl with associated choanal atresia

Dyskeratosis congenita is a rare, progressive, degenerative disorder characterized by cutaneous and mucosal involvement in the first decade of life with malignant changes and bone marrow failure in the second and third decades. The primary inheritance pattern is X-linked recessive, with the majority of cases presenting in boys. We report dyskeratosis congenita in an adolescent girl with choanal atresia, a previously unreported association.     

A case of dyskeratosis congenita associated with impaired DNA repair as shown by the comet assay.

An 18-year old boy with dyskeratosis congenita is presented. To examine the DNA metabolism of our patient, we applied the comet assay, a simple, quick and sensitive method that so far has not been used in this disease. After exposure to UVB, cells originating from the patient present abnormal DNA repair localized in the late step. We consider that such repair deficiency could be related to susceptibility to cancer. The comet assay seems to be a good procedure to investigate dyskeratosis congenita or other genodermatoses.     

Pulmonary Arteriovenous Malformations in Dyskeratosis Congenita

Pulmonary arteriovenous malformations (PAVMs) are rare lesions known to cause cyanosis due to abnormal communication between the pulmonary arteries and veins. They are commonly seen in association with hereditary hemorrhagic telangiectasia, congenital heart disease, hepatopulmonary syndrome, and portopulmonary shunting, but rarely in patients with dyskeratosis congenita (DC). We describe a patient previously diagnosed with DC confirmed to have microscopic PAVMs after bone marrow transplantation and discuss possible pathogenic mechanisms.     

先天性角化不良6例

报道6例先天性角化不良，均有典型的临床表现，即皮肤异色症样皮损、指趾甲萎缩脱落和粘膜白斑等。其中1例伴有再生障碍性贫血。5例患者的皮损曾行组织病理学检查，其改变均与本病相符。     

Uncommon vascular naevi associated with focal acantholytic dyskeratosis

Cutis marmorata telangiectatica congenita and vascular twin naevi are rare vascular anomalies in which focal acantholytic dyskeratosis is usually not observed. We describe a 44-year-old-man who presented for evaluation of skin lesions that had been present since birth. Physical examination revealed anaemic macules adjacent to a naevus telangiectaticus on the chest. Naevus anaemicus was also seen on the shoulders, arms, and left leg. There was bluish-reddish reticulate marking of the skin and cutaneous atrophy. Shortening and hypoplasia of the left leg was observed. Histologic examination of two biopsy specimens revealed focal acantholytic dyskeratosis. In vivo confocal laser scanning microscopy showed dilated capillaries and vessels of the upper dermal plexus in the telangiectatic and decreased capillary blood flow in the anaemic skin sites. The findings were consistent with a diagnosis of cutis marmorata telangiectatica congenita, vascular twin naevi, and incidental focal acantholytic dyskeratosis. The particularities of the present case are the following: firstly, the association of two rare vascular anomalies to which the genetic concept of mosaicism can be applied; secondly, the occurrence of incidental focal acantholytic dyskeratosis in sites of vascular naevi.     

X-linked dyskeratosis congenita with pancytopenia

Two maternal male cousins in a Jewish Iraqi kindred were affected with dyskeratosis congenita and had a megaloblastic bone marrow. One cousin had pancytopenia and the other had thrombocytopenia. The kindred displays a deficiency of glucose-6-phosphate dehydrogenase (G6PD) and a beta-thalassemia trait. The following genetic "markers" of the X chromosome were studied: G6PD, the X-linked blood groups Xg, and color vision. Linkage analysis indicated that dyskeratosis, G6PD, and Xg are far apart on the X chromosome. Chromosomal studies showed a 46XY karyotype in both cases; however, nonspecific numerical aberrations and structural abnormalities were found in the first and in the second case, polyploidy was seen in four of 60 cells. The proband's cultured fibroblasts did not show increased susceptibility to malignant transformation by simian virus 40, an oncogenic virus.     

Intracranial calcifications and dyskeratosis congenita

We describe two brothers with dyskeratosis congenita and intracranial calcifications. The calcifications were massive, approximately symmetric, and showed a predilection for the basal ganglia and dentate nuclei. No underlying causes for this finding were identified. Idiopathic familial intracranial calcification of this type has been described, but an association with dyskeratosis congenita has not previously been observed.     

Dyskeratosis congenita in a female

We report a 9-year-old Saudi girl with dyskeratosis congenita. In addition to the known manifestations of this disease, she also had the additional features of tufts of hairs on the limbs, and an early onset of keratinized basal cell papillomas on her trunk.     

Nail manifestations of some important genetic disorders in children

There are some genetic disorders in which nail changes are the major feature, such as the nail patella syndrome and pachyonychia congenita. Nail abnormalities are a constant feature of other disorders such as hidrotic ectodermal dysplasia, dyskeratosis congenita, some forms of epidermolysis bullosa, and ichthyosis follicularis with alopecia and photophobia. Nail changes often occur in mal de Meleda, Papillon–Lefèvre syndrome, and the keratitis-ichthyosis-deafness (KID) syndrome and are an occasional feature in some other ichthyoses and in incontinentia pigmenti. In Goltz syndrome, nail changes can be supportive of the diagnosis in a case in which the other features are minimal or subtle. In Darier disease, nail changes may be the first sign of the disorder and lead to the diagnosis being made. Nail changes may occur in some conditions such as Apert syndrome and Adams–Oliver syndrome as a result of abnormalities of the distal phalanges.     

先天性角化不良的一个新的基因突变

目的 检测一例先天性角化不良(DKC)患者DKC1基因的突变情况。方法 采用PCR技术扩增DKC1基因的15个外显子,然后采用变性高效液相色谱(DHPLC)技术进行基因突变筛查,对筛查结果异常的外显子进行DNA测序:基因突变的验证在100例无相关遗传性疾病的无关男性中进行。结果 患者DKC1基因的第12号外显子呈异常的DHPLC洗脱峰,家庭其他成员及正常群体对照未见此异常洗脱峰。测序结果显示患者DKC1基因第12外显子的1236位碱基由G→T,导致W412C突变,家庭其他成员及正常群体对照均未见此突变。结论 我们检测到的患者DKC1基因W412C是一个新的散发性突变,它可能导致患者先天性角化不良。     

Somatic ATP2A2 mutation in a case of papular acantholytic dyskeratosis: mosaic Darier disease

Papular acantholytic dyskeratosis, also known as acantholytic dermatosis of the vulvocrural (or anogenital) area, is an uncommon eruption reported predominantly in women. This entity manifests with pruritic papules in the groin/anogenital area and less commonly on the chest. The pathobiology of papular acantholytic dyskeratosis is uncertain. A 62‐year‐old woman presented with multiple verrucous‐appearing lesions in the groin and on the chest showing acantholytic dyskeratosis on histopathology. Given histological similarity of these papular acantholytic dyskeratosis lesions to Darier disease due to inherited ATP2A2 mutation, we screened affected and normal tissue and peripheral blood in our patient for mutations in ATP2A2. We found an identical ATP2A2 p.706D>N mutation in multiple independent papular acantholytic dyskeratosis lesions that was not present in uninvolved skin or peripheral blood DNA. These findings establish somatic mosaicism of ATP2A2 mutations as a genetic cause for papular acantholytic dyskeratosis.     

X‐linked dyskeratosis congenita presenting in adulthood with photodamaged skin and epiphora

Dyskeratosis congenita (DC) is a clinically and genetically heterogeneous multisystem bone marrow failure disorder of telomere maintenance, which may present with dermatological features. The main cause of mortality is bone marrow failure, often developing in the second decade of life, although pulmonary disease and malignancies such as squamous cell carcinomas (SCCs) may also prove fatal. We report the case of a 28‐year‐old man with X‐linked DC and confirmed DKC1 gene mutation. In addition to the classic triad of nail dystrophy, hyperpigmentation and oral leucoplakia, the patient had actinic keratosis (AK) and photodamaged skin, hitherto under‐recognized features of this condition. Awareness of the clinical presentation of DC is important, as accurate clinical and molecular diagnosis affords patients and their families genetic counselling, cancer prevention and screening measures, and planning for complications such as bone marrow failure.