一个色素失禁症家系的NEMO基因和假基因△NEMO缺失突变分析

目的 用长链聚合酶链反应进行检测家族性色素失禁症(incontinentia pigmenti,IP)患者的NEMO基因的缺失突变.方法 收集一色素失禁症家系的临床资料,选取NEMO基因特异引物In2/ff3R和假基因△NEMO的特异引物Rev-2/JF3R,采用长链聚合酶链反应对家系内成员NEMO基因和假基因△NEMO的缺失位点进行检测,同时对80名无血缘关系健康对照者的该位点进行同样检测.结果 所有患者皆有NEMO基因和假基因△NEMO基因共有序列NEMO△4-10缺失,而在家系内非患者以及80名正常对照者中均未发现NEMO基因和假基因△NEMO的共有序列NEMO4△-10缺失.结论 该家系为一个典型遗传早现现象的IP家系,NEMO基因和△NEMO的缺失突变导致其发病.长链PCR扩增技术可用于检测NEMO基因的缺失突变,对于遗传咨询具有一定的应用价值.     

Partial sweat gland aplasia in incontinentia pigmenti Bloch-Sulzberger

Dermatoglyphic investigation of palm prints in patients with Incontinentia pigmenti revealed in five of eight cases a partial ridge dissociation with lack of sweat gland pores. This disease can, therefore, be accepted as a second X-linked anhidrotic ectodermal dysplasia, which, however, is only segregated in the female.     

X-inactivation and marker studies in three families with incontinentia pigmenti: implications for counselling and gene localisation

Familial incontinentia pigmenti (IP) is an X-linked dominant disorder with an extremely variable clinical presentation. Ambiguous diagnosis can complicate genetic counselling and attempts to refine the gene location in Xq28. Marked skewing of X-inactivation patterns is a hallmark of IP and provides a means for investigating uncertain cases. We have conducted X-inactivation studies in three families where Xq28 marker studies were at odds with the original clinical assessment. The results indicate that no recombination between the disease locus and Xq28 loci has occurred and suggest that mosaicism is responsible for the discrepancy in one family.     

The gene for incontinentia pigmenti: failure of linkage studies using DNA probes to confirm cytogenetic localization

Probes for restriction fragment length polymorphisms mapping between Xp21 and Xq22.3 have been used in a linkage study of incontinentia pigmenti (IP). Six independent sporadic cases of disorders resembling IP with X-autosome translocations involving the same X chromosome breakpoint (Xp11) have been reported. These observations suggest that the IP gene may be located in the Xp11 chromosomal region. However, the linkage study with DNA probes has failed to confirm this localisation.     

Incontinentia pigmenti: XXY male with a family history

We report on the case of a male who from the start of life displayed vesicular lesions; on the trunk these were clustered and on the limbs they adopted a linear configuration. After biopsy of one such lesion, the histopathological study was compatible with a diagnosis of incontinentia pigmenti (IP). In the following months, hyperkeratotic lesions appeared which later became pigmented. The mother and other female members of the family also showed different degrees of alteration related to the same disease. The karyotype study showed the existence of 47,XXY (Klinefelter syndrome). The exceptional nature of this case is that although it is the third case reported in the literature of a male affected by incontinentia pigmenti with a previous family history, it is the only one combining this characteristic with the presence of a 47,XXY karyotype.     

Male cases of incontinentia pigmenti: Case report and review

Male patients with Bloch-Sulzberger incontinentia pigmenti (IP type II) are rare and more severely affected than their female counterparts, with a significant occurrence of sex chromosome aneuploidy. This document introduces a new male IP type II patient and reviews 48 males reported with IP. Twenty-eight of the 49 patients meet current criteria for diagnosis of IP type II. The phenotype is variable and the incidence of documented developmental delay is 25%. Five patients had Klinefelter syndrome (47,XXY). Most patients were reported prior to 1961 when chromosome analysis was not available. Biopsy and laboratory reports considered to be “consistent with” the diagnosis of IP were seen in patients meeting criteria as well as those who would not currently be given the diagnosis. The histologic findings considered diagnostic are varied. This variability may be accounted for by differences in stage of disease, biopsy site, histologic technique, and reporting style. Conversely, this may indicate that the diagnostic weight given to the biopsy should be reconsidered. Eosinophilia was not a consistent finding. Overall, differences in reporting, ascertainment, and length of follow-up lead to difficulty in interpreting or predicting the natural history of males with IP type II. Based on the existing literature, they appear to have a higher rate of mental retardation than the general population, but there does not appear to be a correlation between severity of physical and mental involvement. The presence of sex chromosome aneuploidy documented in the more recent cases emphasizes the need for chromosome analysis in any male patient suspected of IP type II. Am. J. Med. Genet. 77:201–218, 1998. © 1998 Wiley-Liss, Inc.     

Expression of eotaxin, an eosinophil-selective chemokine, parallels eosinophil accumulation in the vesiculobullous stage of incontinentia pigmenti

Incontinentia pigmenti (IP) is an X-linked dominant genodermatosis primarily affecting female children. The initial vesiculobullous stage of IP is characterized clinically by inflammatory papules, blisters, and pustules, and histopathologically by acanthosis, keratinocyte necrosis, epidermal spongiosis and massive epidermal eosinophil infiltration. The cause of this multisystem disease is attributed to the mutations of an X-linked regulatory gene, termed nuclear factor-kappaB essential modulator (NEMO). The exact mechanism of epidermal eosinophil accumulation has not yet been determined. We explored the possible role of an eosinophil-selective, nuclear factor-kappaB-activated chemokine, eotaxin, in the accumulation of eosinophils in the initial stage of the disease. Monoclonal antibody (6H9) specific for human eotaxin strongly labelled the suprabasal epidermis of IP skin, paralleling the upper epidermal accumulation of eosinophils, but did not label the epidermis of normal skin or lesional skin from patients with other inflammatory skin diseases not characterized by prominent eosinophil accumulation, namely dermatitis herpetiformis and selected cases of atopic dermatitis lacking significant numbers of eosinophils. In addition, endothelial cells in lesional skin of IP also exhibited strong expression of eotaxin, which correlated with perivascular and intravascular eosinophil infiltration. We also examined the in vitro effects on epidermally derived eotaxin of several cytokines that were nuclear factor-kappaB-activated and/or known to induce eotaxin expression. In normal human keratinocytes, proinflammatory cytokines either independently (IL-1alpha) or synergistically (tumour necrosis factor-alpha (TNF-alpha)/ interferon-gamma (IFN-gamma) and TNF-alpha/IL-4) up-regulated eotaxin expression. These studies suggest that release of cytokines during the initial inflammatory stage of IP induces epidermal expression of eotaxin, which may play a role in the epidermal accumulation of eosinophils.     

Gonadal mosaicism for incontinentia pigmenti in a healthy male.

Incontinentia pigmenti (IP) is a genodermatosis that segregates as an X linked dominant trait with male lethality. The disease has been linked to Xq28 in a number of studies. A few affected males have been documented, most of whom have a 47,XXY karyotype. We report a family with two paternally related half sisters, each affected with IP. The father is healthy, clinically normal, and has a 46,XY normal male karyotype. Linkage analysis of 12 polymorphic markers (two X linked and 10 autosomal) confirms paternity. X inactivation studies with the human androgen receptor (HUMARA) indicate that the paternal X chromosome is inactivated preferentially in each girl, implying that this chromosome carries the IP mutation, and that the father is a gonadal mosaic for the IP mutation.     

Incontinentia pigmenti in a newborn male infant with DNA confirmation

We report on a woman with incontinentia pigmenti (IP), who had two successive term pregnancies. The first pregnancy ended in the birth of a male infant, who is alive and well at 2 years. A second liveborn male had early postnatal distress and died after 1 day of life, after a fulminating clinical course. Polymorphic microsatellite markers, closely linked to the IP gene on the X chromosome, showed that each son inherited a different X chromosome from his mother. Although in most instances IP appears to be prenatally lethal for the male, the phenotype is not completely known. We propose that the neonatal phenotype may be characterized by lethal disturbances in the hematopoietic and immunologic systems. Am. J. Med. Genet. 75:159–163, 1998. © 1998 Wiley-Liss, Inc.     

Somatic and germ line mosaicism and mutation origin for a mutation in the L1 gene in a family with X-linked hydrocephalus

X-linked hydrocephalus is caused by mutations in the gene for neural cell adhesion molecule L1 (L1CAM). In this report, we describe identification of a mutation in an isolated case of hydrocephalus with adducted thumbs. Tracing the origin of the mutation within the family showed a degree of somatic mosaicism in the asymptomatic maternal grandfather of the propositus. This report highlights the need to take mosaicism into account when counselling relatives of affected individuals. Am. J. Med. Genet. 75:200–202, 1998. © 1998 Wiley-Liss, Inc.     

Somatic mosaicism in a mother of two children with Pitt–Hopkins syndrome

Steinbusch CVM, van Roozendaal KEP, Tserpelis D, Smeets EEJ, Kranenburg‐de Koning TJ, de Waal KH, Zweier C, Rauch A, Hennekam RCM, Blok MJ, Schrander‐Stumpel CTRM. Somatic mosaicism in a mother of two children with Pitt–Hopkins syndrome. Pitt–Hopkins syndrome (PTHS) is a neurodevelopmental disorder characterized by intellectual disability, unusual face and breathing abnormalities and can be caused by haploinsufficiency of TCF4. The majority of cases are sporadic. Somatic mosaicism was reported infrequently. We report on a proband with typical manifestations of PTHS and his younger brother with a less striking phenotype. In both, a heterozygous frameshift mutation (c.1901_1909delinsA, p.Ala634AspfsX67) was found in exon 19 of TCF4. The same mutation was found at low levels in DNA extracted from the mother's blood, urine and saliva. This report of familial recurrence with somatic mosaicism in a healthy mother has important consequences for genetic counseling. We suggest careful studies in parents of other patients with PTHS to determine the frequency of germline and somatic mosaicism for TCF4 mutations.     

Somatic cell mosaicism: Another source of phenotypic heterogeneity in nuclear families with osteogenesis imperfecta

We report on 2 brothers with arthrogryposis, hyperkeratosis, and severe hypoplasia of dorsal roots and posterior columns in the one sib who was examined at autopsy. This appears to represent a new arthrogryposis syndrome with poor prognosis, most likely inherited as a single gene, either autosomal or X-linked recessive trait. © 1993 Wiley-Liss, Inc.     

A successful treatment of tadalafil in incontinentia pigmenti with pulmonary hypertension

We describe a female infant with incontinentia pigmenti complicated by severe pulmonary arterial hypertension that was markedly improved by tadalafil administration. The infant was referred to our institution because of neonatal seizures and generalized skin rash at the age of 1 day. She was diagnosed with incontinentia pigmenti on skin biopsy findings. In addition to incontinentia pigmenti, she had pulmonary arterial hypertension without structural heart disease. The pulmonary hypertension rapidly worsened at the age of 2 months and was confirmed by cardiac catheterization. The pulmonary artery pressure was equal to systemic pressure but it decreased in response to nitric oxide inhalation. We, therefore, initiated treatment with tadalafil of 1 mg/kg/day. The follow-up cardiac catheterization performed at 9 months revealed dramatic improvement in the pulmonary artery pressure. An IKBKG mutation with deletion of exons 4–10 was detected in the blood of both the patient and her mother. Our experience indicates that tadalafil may be beneficial in treating pulmonary arterial hypertension associated with incontinentia pigmenti.     

Incontinentia pigmenti in Arizona Indians including transmission from mother to son inconsistent with the half chromatid mutation model

Incontinentia pigmenti (IP) is an X-linked dominant disease, usually lethal to males. To explain occasional sporadic IP males, the half chromatid mutation model (Gartler & Francke 1975) has been invoked (Lenz 1975). We here report four cases of American Indians with IP. Two girls had sporadic IP. One affected boy's mother had IP. This is the first report of mother-to-son transmission of IP, indicating that a male with an inherited whole chromatid mutation for IP can escape lethality.     

Gene for incontinentia pigmenti maps to band Xp11 with an (X;10) (p11;q22) translocation

Incontinentia pigmenti (IP) is a genetic disease that is usually lethal in males. We report finding an X;10 translocation in a girl with IP. Three other X/autosome translocations have been observed in females with IP: two involving chromosome 9 and one involving chromosome 17. The breakpoint in all four cases in the X chromosome was in band Xp11. The IP gene locus can therefore be confidently assigned to the X chromosome and, specifically, to band Xp11. The IP gene is most likely to subband Xp11.2. We propose that IP may prove to be a submicroscopic deletion.     

Genetic counselling in hypomelanosis of Ito: case report and review

A 27-year-old male with hypomelanosis of Ito (HI) is reported. One of his two children had a postaxial ray defect of one leg but neither had cutaneous features of HI. Somatic mosaicism for a gene defect lethal to ectodermal derivatives offers the best explanation for HI in males, with consequent negligible recurrence risk. The limb defect is considered coincidental. The excess of girls with HI could be due to a female cohort with incontinentia pigmenti (IP) which may be indistinguishable: counselling of females must therefore take account of possible X-linked inheritance.