Bloch-Sulzberger's syndrome – a hereditary form of violation of pigmentation of skin which is often combined with malformations of teeth, hair, nails and eyes. Symptoms of a disease are characterized by the expressed staging – at first on skin eritematozny rash in the form of spots and lines develops, then on its place develops , replaced by spots and the subsequent hypopigmentation with an atrophy of integuments. Diagnostics of a syndrome of Bloch-Sulzberger is made on the basis of data of the present status of a sick, histologic research of samples of skin in the field of defeat, studying of the hereditary anamnesis and molecular and genetic analyses. Specific treatment of this pathology does not exist for today, use the symptomatic and supporting actions of various character.
Bloch-Sulzberger's syndrome (a family form of an incontience of a pigment, neuroskin ) – the genetic disease which is characterized by violation of metabolism of melanin in skin and a number of the accompanying malformations. For the first time this disease was described in 1926 by the Swiss dermatologist B. Bloch, then more detailed studying of this pathology was carried out by the American pediatrician M. Sulzberger in 1929 and, irrespective of the previous researchers, the German doctor G. Simens. For this reason it is possible to find other name of this disease in literature – Bloch Siemens syndrome. It was succeeded to find out that pathology is inherited it is linked to the H-chromosome, at the same time mutant the allele is prepotent. For this reason Bloch-Sulzberger's syndrome many times over meets at girls more often – sexual distribution makes about 6:210 as presence of this mutation at male embryos practically always is lethal and leads to spontaneous termination of pregnancy. Development of a disease in boys can be caused by a genetic mosaicism, existence of accompanying Klaynfelter's syndrome or rare dot "soft" mutations. The general occurrence of a syndrome of Bloch-Sulzberger makes about 1 case on 75 000 newborns.
Reasons of a syndrome of Bloch-Sulzberger
At Bloch-Sulzberger's syndrome there is a damage of a gene of IKBKG which settles down on the H-chromosome. A product of its expression is multipurpose complex protein – a regulatory subjedinitsa of the NEMO inhibitory kinase participating in alarm system of an important transkriptsionny factor (NF-kappa-B). This factor and the alarm way corresponding to it regulates a huge number of various processes in a human body – participates in processes of adaptation at a stress, the immune answer, some forms of inflammatory reactions, processes of cellular adhesion, and also slows down processes of apoptosis. Most often large translocations and deletion of a gene of IKBKG therefore the expression and release of protein from this gene completely stop become the reason of a syndrome of Bloch-Sulzberger.
As women have two H-chromosomes, in the presence of the second normal allele of a gene of IKBKG such mutation does not threaten life, but causes development of a syndrome of Bloch-Sulzberger. Is known the fact that in somatic cells of a female body only one H-chromosome whereas the second is condensed in sexual chromatin is always active. Considerable variability of expressiveness of symptoms of a disease is caused by distribution of cages where the chromosome with a mutant form of a gene IKBKG is active. As a result, in the above-stated cages the regulatory subjedinitsa of a NEMO inhibitory kinase is not formed, as leads to the characteristic malformations forming a clinical picture of a syndrome of Bloch-Sulzberger. Skin symptoms are connected with violation of permeability of membranes of melanotsit (therefore practically all pigment freely leaves cages) and autoimmune reactions.
Unlike women, men normal have only one H-chromosome therefore in the presence a nonsense mutation in IKBKG gene release of important protein does not happen absolutely in all cages of an organism. It becomes the reason of massive apoptosis of hepatocytes at a stage of pre-natal development – normal this process is late just the NF-kappa-B system. Development of violations, similar to Bloch-Sulzberger's syndrome, at boys perhaps in the presence of accompanying Klaynfelter's syndrome (XXY karyotype) or a genetic mosaicism when only a part of cages in an organism has defect of a gene of IKBKG. In recent years dot mutations of this gene which do not lead to a full stop of a transcription were revealed, but change structure of final protein. However most often boys with such defects have not a syndrome of Bloch-Sulzberger, but other genetic diseases – ektodermalny a dysplasia, immunodeficiencies, skeleton malformations.
Symptoms of a syndrome of Bloch-Sulzberger
One of the most expressed and widespread manifestations of a syndrome of Bloch-Sulzberger is the dermatosis which is found at the birth or (less often) arises for the first days of life of the newborn. In development of changes of integuments at this pathology characteristic staging is observed that is also an important diagnostic sign. Localization of such changes – on the side surfaces of extremities, trunks, necks, along Sharko's lines or projections of the main nervous trunks. Four main stages of skin symptoms of a syndrome of Bloch-Sulzberger are in most cases allocated:
The 1st stage – inflammatory or vezikulobullezny. Begins at the birth of the patient or for 2-3 weeks of life and lasts to age of 3-8 months. At this stage of a disease there are vesicles, eritematozny rash, development of bubbles and is possible. Taking into account age of patients with Bloch-Sulzberger's syndrome there is a certain risk of infectious complications on affected areas of skin.
The 2nd stage – hypertrophic or verrukozny. It is characterized by development on affected areas of a body of a giperkeratoz in the form of plaques, warty and likhenoidny growths. Their distribution, as a rule, symmetric and linear, along Sharko's lines or projections of nervous trunks. Duration of this stage of a syndrome of Bloch-Sulzberger makes several months (to age of one year), at some patients can be absent.
The 3rd stage – pigmentary. At this stage of a disease patients on affected areas of skin have centers of a hyperpegmentation of various forms and the extent of dark brown color. Almost at a half of patients with Bloch-Sulzberger's syndrome such centers appear on not changed parts of the body and are not connected with the rashes characteristic of the previous stages. Duration of a hyperpegmentation makes several years, usually – till the puberty period.
The 4th stage – atrophic. It is characterized by loss of a pigment on the defeat centers with development of signs of an atrophy of skin. At some patients with Bloch-Sulzberger's syndrome such manifestations can be expressed very poorly, in some cases disease symptoms completely disappear after completion of puberty.
Besides skin manifestations, Bloch-Sulzberger's syndrome can lead to development of a focal alopetion, dystrophy of nails. Almost at 80% of patients anomalies of a tooth alignment – a curvature, lack of teeth are noted. In half of cases sight violations – a cataract, squint, an atrophy of an optic nerve and some other frustration come to light. Intellectual development at Bloch-Sulzberger's syndrome usually does not suffer, but some delay is possible. It is in rare instances noted mental retardation. All displays of a disease tend to easing after end of the teenage period.
Diagnostics and treatment of a syndrome of Bloch-Sulzberger
For definition of a syndrome of Bloch-Sulzberger use a set of diagnostic methods and the technician – dermatological survey, studying of the hereditary anamnesis, a histologic research of affected areas of integuments, molecular and genetic analyses. At survey come to light various (depending on age of patients and a stage of a disease) changes of skin of eritematozny, vesicular or giperkeratichesky character, at the senior patients can be defined focal hyper - or hypopigmentation of skin. Besides these manifestations, at Bloch-Sulzberger's syndrome dystrophy of nails, an alopetion, anomalies of a structure of teeth is possible.
The hereditary anamnesis can reveal the family, prepotent and linked to the H-chromosome nature of inheritance of pathology. In certain cases at the patient's mother in the anamnesis several cases of spontaneous termination of pregnancy are noted – it is connected with pre-natal death of a male fruit. Results of a histologic research of tissues of skin at Bloch-Sulzberger's syndrome depend on a disease stage – at the first stage development of the epidermalny bubbles filled with eosinophils and fibrinous masses is found . At the second stage of pathology signs of a vnutriepitelialny keratinization, and come to light, in a term hypostasis with neytrofilny and eozinofilny infiltration is noted. At the third stage of a syndrome of Bloch-Sulzberger inflammatory changes in a term (hypostasis, infiltration) disappear, but considerable accumulation of a pigment in the top layers of skin is observed. The fourth stage is characterized by disappearance of a pigment, development of fibrous fabric and partial disappearance of appendages of skin.
Molecular and genetic diagnostics of a syndrome of Bloch-Sulzberger is carried out by the doctor geneticist and can be made by several main technicians. The direct automatic sekvenirovaniye of the sequence of a gene of IKBKG allows to reveal practically any changes in its structure. Translocations and deletion of considerable sites of a gene which are often acting as the reason of a syndrome of Bloch-Sulzberger can be found by means of a FISH analysis technique. This disease can be also confirmed by means of a research of an inactivation of H-chromosomes in cells of the struck fabrics.
Specific treatment of a syndrome of Bloch-Sulzberger does not exist for today, skin defeats at an inflammatory stage of a disease are processed by antiseptics and solutions for prevention of infectious complications. Besides, local purpose of glucocorticoid steroids for reduction of an inflammation is recommended, however such treatment should be made with care, considering high permeability of integuments at children of younger age. Other manifestations of a syndrome of Bloch-Sulzberger (malformations of teeth, eyes) treat in the presence of indications.
Forecast and prevention of a syndrome of Bloch-Sulzberger
The forecast of a syndrome of Bloch-Sulzberger most often favorable as from the moment of the beginning of puberty of display of a disease considerably weaken. Changes of internals, nervous system, eyes which violations are occasionally observed at this pathology can worsen the forecast. Besides, in some cases Bloch-Sulzberger's syndrome there can be primary immunodeficiency which also considerably worsens prospects of a disease. Prevention of pathology comes down only to prenatal diagnostics and medico-genetically consultation of parents at the burdened heredity at future mother.