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Incontinentia pigmenti: Xp breakpoint is not the same in a case of r(X) and in X/autosome translocations.

X-specific DNA probes were used to characterize the r(X) of a 45,X/46,X,r(X) female patient with Incontinentia pigmenti. It was found to be of maternal origin. Breakpoints were shown to be in or distal to p11.22 and between q12.2 and q13.1. When considering all known cases of Incontinentia pigmenti and X rearrangements at least four different break sites on the X have been shown.

Chromosome Aberrations↗

Genetics of pigmentary disorders.

The genetic and molecular bases of various types of congenital pigmentary disorders have been classified in the past 10 years, as follows: (1) disorders of melanoblast migration in the embryo from the neural crest to the skin: piebaldism; Waardenburg syndrome 1-4 (WS1-WS4); dyschromatosis symmetrica hereditaria. (2) Disorders of melanosome formation in the melanocyte: Hermansky-Pudlak syndrome 1-7 (HPS1-7); Chediak-Higashi syndrome 1 (CHS1). (3) Disorders of melanin synthesis in the melanosome: oculocutaneous albinism 1-4 (OCA1-4). (4) Disorders of mature melanosome transfer to the tips of the dendrites Griscelli syndrome 1-3 (GS1-3). These disorders are presented and their gene mutations and pathogenesis are discussed.

Cell Movement↗

Melanin pigmentary disorders: treatment update.

Most of the melanin pigmentary disorders are cosmetically important and have a strong impact on the quality of life of affected individuals. This article examines recent advances in the treatment of melanin pigmentary disorder including hypermelanosis and hypomelanosis. The development of laser technologies has completed the use of the increasing number of bleaching agents in treating hyperpigmented lesions. The treatment of hypomelanotic disorders is still often disappointing, but new therapeutic options provide encouraging results.

Dermatologic Agents↗

Dermal melanocytosis: a clinical spectrum.

While most dermal melanocytoses are congenital or have an onset in early childhood, there is a group which is clearly acquired, with an onset in adult life. While the Mongolian spot typically disappears in childhood, other dermal melanocytoses persist for life. A brief review of the clinical spectrum of the dermal melanocytoses is undertaken and three illustrative cases are described: a case of congenital naevus of Ota, a case of acquired bilateral naevus of Ota-like macules, and an unusual case of a congenital dermal melanocytotic lesion on the left had which began to spread in adulthood. The possibilities regarding the pathogenesis of this intriguing group of disorders are considered.

Adult↗

Development of pigment cells in the zebrafish embryo.

In recent years, the zebrafish Danio rerio has emerged as a powerful model organism for the study of vertebrate embryogenesis. Zebrafish, like other vertebrates, possess pigment cells that arise from two distinct embryonic sources: those of the dermis and epidermis originate from the neural crest, while those that comprise the outermost layer of the retina, the retinal pigment epithelium or RPE, derive from the optic cup. A better understanding of processes behind the specification and differentiation of these cells will provide insight to the evolutionary diversification of all classes of vertebrates and will have clinical relevance to human disorders of pigmentation and certain retinopathies. In the first part of this review, the present knowledge of the ontogeny of both of these populations of pigment cells in the embryonic zebrafish is summarized, in terms of both genetics and molecular markers. The final part of the review focuses on duplicate zebrafish genes encoding orthologs of the basic helix-loop-helix/leucine zipper protein Mitf (Microphthalmia-associated transcription factor), and presents a hypothesis concerning their divergent roles in neural crest and retinal pigment cells.

Animals↗

Steatocystoma multiplex and leuconychia in a child with Alagille syndrome.

Alagille syndrome is a rare autosomal dominant developmental disorder, characterized by congenital paucity of interlobular bile ducts, peculiar facies, posterior embryotoxon, bone abnormalities, and peripheral pulmonary artery stenosis. Cutaneous involvement in this disorder is quite rare and the association of Alagille syndrome with multiple comedones and cysts has been described only once. Here, we report the clinical and histological findings of a 7-year-old patient affected by Alagille syndrome who presented multiple cystic lesions and comedones reminiscent of steatocystoma multiplex and a congenital total true leuconychia. Although unexplained, the association of this syndrome with a developmental disorder of the pilosebaceous unit may not be fortuitous.

Alagille Syndrome↗

Disseminated hypopigmented keratoses.

We present two cases of asymptomatic, widespread keratotic eruptions in young female patients. Clinically, the lesions are well-demarcated, small, hypopigmented, flat-topped papules occurring on the trunk and extremities in a uniform distribution. Skin biopsy specimens from one patient revealed hyperorthokeratosis, papillomatosis, and a normal amount of melanin. We suggest that this is a newly recognized dermatologic entity that may be descriptively termed disseminated hypopigmented keratoses. Disseminated hypopigmented keratoses may be distinguished by clinical and histologic criteria from similar keratotic eruptions. Since the lesions of disseminated hypopigmented keratoses are both inconspicuous and asymptomatic, it is likely that the disorder is more prevalent than our two cases would suggest.

Adult↗

The ectodermal dysplasias.

In order to be considered an ectodermal dysplasia, a disorder should meet the following criteria: it must be congenital; it must be diffuse (not localized) and must involve the epidermis as well as at least one of its appendages; and it must not be progressive. Included is a discussion of some well-documented, as well as some newer, conditions about which there appears to exist enough information to make some decisions concerning their categorization.

Arthrogryposis↗

A patient with Cronkhite-Canada syndrome, myxedema and muscle atrophy.

A case of Cronkhite-Canada syndrome is presented. The patient had alopecia, onychodystrophy and gastrointestinal polyposis, mainly in the stomach and duodenum, with transient diarrhea and hypoproteinemia. Marked atrophy and weakness of the shoulder girdle muscles due to myopathy were also present. In addition she had primary hypothyroidism. The outcome of the disease is usually fatal within months, but so far our patient is alive four years after the onset of symptoms. The pathological changes, pathophysiology, symptoms, course and treatment of this rare disorder of unknown etiology are discussed.

Aged↗

Cutis tricolor parvimaculata: a distinct neurocutaneous syndrome?

An 11-year-old girl had multiple, disseminated, rather small café-au-lait macules and hypochromic spots involving the neck, the trunk and the legs. In part, the two types of macules showed a spatial proximity, suggesting didymosis (twin spotting). The term cutis tricolor has been proposed to describe congenital paired hyperchromic and hypochromic macules on a background of intermediate skin. Because the spots present in this case were much smaller than those described in previous cases of cutis tricolor, we here propose the distinguishing term 'cutis tricolor parvimaculata'. The underlying gene locus may be a hot spot for postzygotic recombinations, giving rise to multiple twin spots. Moreover, the girl had developed seizures from the age of 10 years, and a large oligodendroglioma involving the left frontal lobe was found. A causal relationship between the cutaneous phenotype and the cerebral tumor is unproven but likely. The skin lesions were reminiscent of a disorder described by Westerhof et al. in 1978 under the term 'hereditary congenital hypopigmented and hyperpigmented macules'. So far, however, it is not clear whether cutis tricolor parvimaculata is identical with or different from this disorder.

Brain Neoplasms↗

Clinical features in 27 patients with Angelman syndrome resulting from DNA deletion.

We report the clinical features in 27 Australasian patients with Angelman syndrome (AS), all with a DNA deletion involving chromosome 15(q11-13), spanning markers from D15S9 to D15S12, about 3 center dot 5 Mb of DNA. There were nine males and 18 females. All cases were sporadic. The mean age at last review (end of 1994) was 11 center dot 2 years (range 3 to 34 years). All patients were ataxic, severely retarded, and lacking recognisable speech. In all patients, head circumference (HC) at birth was normal but skewed in distribution, with 62 center dot 5% at the 10th centile. At last review HC was around the 50th centile in three patients (12 center dot 5%) while 15 had poor postnatal head growth. Short stature was not invariable, 5/26 (19%) were on or above the 50th centile. Hypotonia at birth was recorded in 15/24 (63%) and neonatal feeding difficulties were recorded in 20/26 (77%). Epilepsy was present in 26/27 (96%) with onset by the third year of life in 20 patients (83%). Improvement in epilepsy was reported in 11/16 patients (69%) with age. An abnormal EEG was reported in 25/25 patients. Hypopigmentation was present in 19/26 (73%). One patient had oculocutaneous albinism. Five patients could not walk independently. Of the remaining 22 who could walk, age of onset of walking ranged from 2 to 8 years. Disrupted sleep patterns were present in 18/21 patients (86%), with improvement in 9/12 patients (75%) over 10 years of age. The clinical features in this group of deletional AS patients were similar to previous reports, but these have not separated patients into subgroups based on DNA studies. In our group of deletional cases, 100% showed severe mental retardation, ataxic movements, absent language, abnormal EEG, happy disposition (noted in infancy in 95%), normal birth weight and head circumference at birth, and a large, wide mouth. These features occurred with a higher frequency than in AS patients as a whole. Our study also provided information on the evolution of the phenotype. The data can act as a benchmark for comparisons of AS resulting from other genetic mechanisms.

Adolescent↗

Correction of symptoms of platelet storage pool deficiency in animal models for Chediak-Higashi syndrome and Hermansky-Pudlak syndrome.

Two human diseases of platelet storage pool deficiency (SPD), Hermansky-Pudlak syndrome and Chediak-Higashi syndrome, are recessively inherited disorders characterized by hypopigmentation, prolonged bleeding, and normal platelet counts accompanied by a reduction in dense granule number. We have recently described seven independent recessive mutations in the mouse regulated by separate genes which are likely animal models for human SPD. Reciprocal bone marrow transplants were carried out between normal C57BL/6J mice and two of these mutants, beige and pallid, in order to test whether the platelet defects are due to a defect in platelet progenitor cells or to humoral factors. Normal and congenic mutant mice were transplanted with marrow after 950 rad whole body radiation. The long bleeding times and low serotonin concentrations of the two mutants were converted to normal values after transplantation with normal marrow. Likewise, normal mice displayed symptoms of SPD when transplanted with mutant marrow. These studies demonstrate that with each of the two mutations, platelet SPD results from a defect in bone marrow precursor cells. Also, the studies suggest that in severe cases, platelet SPD may be successfully treated by bone marrow transplantation.

Animals↗

Hypomelanosis of Ito--a nonspecific marker of somatic mosaicism: report of case with trisomy 18 mosaicism.

We report on a patient with hypomelanosis of Ito (HI), developmental delay, recurrent pneumonia, and facial asymmetry. Chromosome analysis done on blood and on one of three skin biopsies showed trisomy 18 mosaicism. This is the first report of HI associated with trisomy 18 mosaicism. This neuroectodermal disorder appears to be a nonspecific manifestation of chromosome mosaicism.

Chromosomes, Human, Pair 18↗

Sex-linked chondrodysplasia punctata?

Widespread atrophic lesions and pigmentary disturbances of the skin distributed in a linear or whorled pattern, are seen in some patients with chondrodysplasia punctata of the Conradi-Hünermann type. Arguments are presented in favor of the hypothesis that this association of anomalies constitutes a distinct genetic disorder, which is inherited as an X-linked dominant trait lethal in hemizygous males.

Adolescent↗

[Ito hypomelanosis (incontinentia pigmenti achromians)].

Authors report the case of a white male patient suffering from a rare neurocutaneous dysplasia. Macrocrania and right ventricular dilation of the brain were present at birth. Motor milestones were delayed and epilepsy with staring spells started at the age of 6 months. On examination at 2 years of age hypopigmented areas of linear distribution were noted on the right extremities and on the right side of the trunk, beyond macrocrania, psychomotor and mental delay. Cranial MRI performed at 5 years of age proved predominantly right-sided megalencephaly, gray matter heterotopia within the right hemispherium and polymicrogyria in the perisylvian region. The EEG was characterized by high-amplitude rhythmic theta activity over the right frontal area. Hypomelanosis of Ito was diagnosed. Authors call attention on the importance of skin lesions in neuropediatric disorders, and give a brief review of the literature in hypomelanosis of Ito.

Abnormalities, Multiple↗