El niño plateado: Síndrome de Chediak-Higashi / The Silver Child: Chediak-Higashi Syndrome

El Síndrome de Chediak-Higashi (SCH) es una patología de herencia autosómica recesiva debido principalmente a mutaciones del gen regulador del tráfico lisosómico (LYST), causando grados dermatológicamente diferentes de albinismo óculocutáneo, infecciones recurrentes, disfunción fagocítica primaria, en el desarrollo y proliferación de todas las líneas celulares. Se presenta caso de preescolar masculino de 2 años de edad, ingresado por aumento de volumen bilateral en región cervical y fiebre, en malas condiciones generales, con áreas de hiperpigmentación en piel, cabello y cejas de coloración grisácea, adenopatías generalizadas y visceromegalias; leucocitosis con linfocitosis y neutropenia, anemia, trombocitopenia, hipoalbuminemia, hipertrigliceridemia e hiperferritinemia; en vista de la infrecuente coexistencia de dichas características con albinismo óculocutáneo; es evaluado por hematología y dermatología evidenciándose inclusiones citoplasmáticas y melanosomas gigantes, respectivamente, compatibles con SCH, confirmándose diagnóstico. El conocimiento del SCH es importante para la oportuna sospecha clínica-diagnóstica e inicio de protocolos terapéuticos en consenso, que garanticen un manejo eficaz para su sobrevida(AU)

Chediak-Higashi syndrome (SCH) is an auto somal recessive in herited pathology mainly due to mutations ofthe LYST gene, causing dermatologically different degrees of oculocutaneous albinism, recurrent infections, primary phagocytic dysfunction, in the development and proliferation of all cell lines. We present a case of a 2-year-old male preschool, admitted due to bilateral volume increase in thecervical region and fever, in poor general conditions, with areas of hyperpigmentation in skin, hair and eyebrows of grayish coloration, generalized lymphadenopathy and visceromegaly; leukocytosis with lymphocytosis and neutropenia, anemia, thrombocytopenia, hypoalbuminemia, hypertriglyceridemia,and hyperferritinemia; in view of the infrequent coexistence of these characteristics with oculocutaneous albinism; it isevaluated by hematology and dermatology, showing cytoplasmicinclusions and giant melanosomes, respectively, compatiblewith SCH, confirming the diagnosis. Knowledge of SCH is important for timely clinical-diagnostic suspicion and initiation of consensus therapeutic protocols that guarantee effective management for survival(AU)

Clinical and molecular genetic analysis of Angelman syndrome with oculocutaneous albinism type 2: A case report and literature review / 北京大学学报(医学版)

To summarize the clinical diagnosis and treatment process and genetic test results and characteristics of one child with Angelman syndrome (AS) complicated with oculocutaneous albinism type 2 (OCA2), and to review the literature. "Angelman syndrome" "P gene" and "Oculocutaneous albinism type 2" were used as keywords to search at CNKI, Wanfang, and PubMed databases (from creation to December 2019). Then all the patients were analyzed. The patient in this study was a girl aged 1 year. After birth, she was found to present as white body, yellow hair, and nystagmus. She could raise her head at the age of 2 months and turn over at the age of 7 months. The head circumference was 42 cm and she could not sit alone or speak at present. Trio-based exome sequencing revealed that the patient carried a homozygous mutation of c.168del (p.Gln58ArgfsTer44) in the P gene, and her father was heterozygous and her mother was wild-type. The detection of copy number variation showed deletion on the maternal chromosome at 15q11.2-13.1 region (P gene located in this region) in the patient. Until December 2019, a total of 4 cases in the 4 literature had been reported. Adding our case here, the 5 cases were summarized and found that all the cases showed white skin, golden hair, and shallow iris after birth. Comprehensive developmental delay was found around 6 months of age after birth, and the language remained undeveloped in 2 cases till follow-up into childhood. Seizures occurred in 4 patients. Two cases had ataxia. All the 5 cases had acquired microcephaly. Two cases had a family history of albinism. Electroencephalogram monitoring was completed in 3 cases and the results were abnormal. Genetic tests showed that all the 5 cases had deletion on maternal chromosome at 15q11-13 region. Four cases carried mutation of P gene on paternal chromosome. And 1 case was clinically diagnosed as OCA2 without P gene test. AS combined with OCA2 is relatively rare. OCA2 is easily diagnosed based on the obvious clinical manifestations after birth. When combined with clinical manifestations such as neurodevelopmental delay, it might indicate the possibility of AS that is hardly diagnosed clinically at an early stage. Genetic tests can reveal the cross-genetic phenomenon of AS and OCA2 and the complex of them can be eventually diagnosed.

Genetic testing and prenatal diagnosis for thirteen Chinese pedigrees affected with oculocutaneous albinism / 中华医学遗传学杂志

OBJECTIVE@#To identify the causative variants in 13 Chinese pedigrees affected with oculocutaneous albinism (OCA) so as to provide genetic counseling and prenatal diagnosis to them.@*METHODS@#Thirteen unrelated pedigrees with clinically diagnosed OCA were collected and classified based on the manifestation of skin and eyes. With informed consent obtained from the participants, peripheral blood samples were collected from the probands and their family members for the extraction of genomic DNA. Candidate variants were screened by targeted capture and next generation sequencing, and the results were validated by Sanger sequencing. Prenatal diagnosis was provided to the families upon their subsequent pregnancies.@*RESULTS@#Causative variants were detected in all probands, including 10 with compound heterozygotes or homozygotes for TYR gene variants and 3 with compound heterozygotes for OCA2 gene variants. Among these, two variants [TYR: c.650G>C (p.Arg217Pro) and OCA2: c.516-2A>T] were unreported previously. The pathogenicity of the novel TYR: c.650G>C (p.Arg217Pro) variant was verified through bioinformatic analysis and prediction of three dimensional structure of the protein. Prenatal diagnosis was provided to 6 fetuses with a high risk for OCA. Four fetuses were found to be carriers, one did not carry the variants of the proband, and one was affected with OCA.@*CONCLUSION@#Identification of the pathogenic variants in the 13 probands, including 2 novel ones, has expanded the mutational spectrum of OCA and enabled genetic counseling and prenatal diagnosis for the families.

Non-invasive prenatal detection of ocutaneous albinism type I based on cfDNA barcode-enabled single-molecule test / 中华医学遗传学杂志

OBJECTIVE@#To assess the value of non-invasive prenatal testing based on cfDNA barcode-enabled single-molecule test (cfBEST) for the prenatal diagnosis of oculocutaneous albinism type I in a family.@*METHODS@#Prenatal genetic diagnosis was carried out by using the cfBEST-based method as well as invasive prenatal diagnosis through amniocentesis. The outcome of the pregnancy was followed up.@*RESULTS@#Non-invasive prenatal testing based on cfBEST showed a fetal DNA concentration of 6.6%, with the proportion of c.929_930insC (p.Arg311Lysfs*7) and c.1037-7T>A mutations being 45.7% and 0%, respectively. The posterior frequency of the negative results was 1, suggesting that the fetus carried neither of the two mutations. The result was consistent with that of invasive prenatal diagnosis, and the follow-up found that the fetus was normal.@*CONCLUSION@#Non-invasive prenatal testing based on cfBEST can be used to detect maternal and fetal genotypes in maternal cell-free DNA, which is clinically feasible.

Study on TYR gene variant from a pedigree with oculocutaneous albinism / 中华医学遗传学杂志

OBJECTIVE@#To analyze gene variants in a Chinese pedigree with oculocutaneous albinism (OCA).@*METHODS@#Gene sequencing of the proband and his parents was performed using chip capture high-throughput sequencing and Sanger sequencing techniques, and PolyPhen-2, SIFT, MutationTaster, and FATHMM software were used to predict the function of new variants. At the same time,the pedigree and variant genes of 4 albinism patients from this pedigree were analyzed.@*RESULTS@#Sequencing results showed that the proband's TYR gene (NM_000372) has c.230G>A (p.Arg77Gln) and c.120_121insG (p.Asp42GlyfsTer35) compound heterozygous variants. The proband's father carries c.230G>A heterozygous variant, and the mother carries c.120_121insG heterozygous variant, indicating that the proband's two variants are from his father and mother. The former is a known missense variant, which can cause abnormal or loss of the original function of the protein polypeptide chain. The latter c.120_121insG(p.Asp42GlyfsTer35) is an unreported frameshift variant of the TYR gene subregion (EX1; CDS1). PolyPhen-2, SIFT, MutationTaster and FATHMM predictions are all prompted as "harmful variants". This variant caused the amino acid encoded protein to terminate prematurely, producing a truncated protein, which eventually formed a 76-amino acid short-type TYR protein instead of the 529-amino acid wild-type TYR protein. Through the pedigree analysis, the four patients in the pedigree are all of the same type of compound heterozygous variants, and the disease-causing genes are all from the patient's parents. They belong to a special form of consanguineous marriage within 5 generations.@*CONCLUSION@#The compound heterozygous variants of c.230G>A (p.Arg77Gln) and c.120_121insG (p.Asp42GlyfsTer35) of the TYR gene may underlie the disease in this pedigree. The gene sequencing results enrich the variant spectrum of the TYR gene, and has facilitated molecular diagnosis for the patient.

Molecular detection of albinism gene in Brazilian buffalo herds (Bubalus bubalis) / Detecção molecular do gene do albinismo em rebanhos de búfalos (Bubalus bubalis) do Brasil

Albinism is a genetic disease characterized by deficient melanin production making affected animals more susceptible to skin problems, negatively influencing production systems of the same. In buffalo, a nonsense mutation (c.1431G>A) in the tyrosinase gene was already described, which is responsible for the oculocutaneous albinism buffalo phenotype. However, prevalence studies have never been performed for this anomaly in Brazil. Therefore, the objective of this study was to investigate this mutation in buffalo herd in Brazil. Of the 315 buffalo tested with no albinism phenotype evident, 11 (3.5%) were heterozygous for the mutation and none were mutated homozygous, showing the existence of the albinism gene in buffalo production herds and proving the importance of prevalence studies for hereditary diseases in order to prevent the dissemination of these same genes and their negative productivity consequences.(AU)

O Albinismo é uma doença genética caracterizada pela deficiência na produção de melanina, o que torna os animais afetados mais susceptíveis a problemas cutâneos e influencia negativamente a criação destes animais. A mutação nonsense (c.1431G>A) no gene da tyrosinase já foi descrita como responsável pelo albinismo oculocutâneo em búfalos, entretanto estudos prévios sobre a prevalência dessa mutação ainda não foram realizados no Brasil. Portanto, o objetivo deste estudo foi avaliar a presença desta mutação em uma população de búfalos brasileiros. Foram genotipados 315 búfalos clinicamente normais, ou seja, sem o fenótipo albino evidente. Desses, 11 (3,5%) eram heterozigotos para a mutação (N/TYR) e os demais eram homozigotos selvagens (N/N). Este resultado demonstra que o alelo mutado para o albinismo em búfalo está presente no rebanho brasileiro e aponta a importância de estudos de prevalência de enfermidades hereditárias com o objetivo de prevenir a disseminação desses alelos mutados, minimizando os prejuízos.(AU)

Clinico-epidemiologic features of oculocutaneous albinism in northeast section of Cairo - Egypt

Oculocutaneous albinism [OCA] is a genetically heterogeneous group of disorders characterized by the absence or reduced pigmentation of the skin, hair and eyes. To assess the clinico-epidemiologic features of different forms of OCA among Egyptian patients, we performed a retrospective study to determine the frequency, types, clinical presentation and associated genomic errors in albino patients and their relatives consulting the Genetics Clinic, Pediatric Hospital, Ain Shams University, Cairo, Egypt. We used the outpatients index files to identify diagnosed cases of albinism referred from the dermatologic and ophthalmologic departments with different genodermatoses over 43 year period. We used specifically designed data collection protocol forms to extract epidemiological and clinical data from the patients medical records. These were entered into a computer database and analyzed using standard statistical software. The occurrence rate of albinism in our study was 20.4% of genodermatoses patients and 1 per 5843 patients attending the Pediatric hospital. Consanguineous marriage was reported among parents of 66.37% of patients and positive family history was reported in 46.01% of patients. Complete OCA was detected in 48.59% of patients, partial albinism in 41.59% of patients and syndromic albinism was detected in 7.96%. Associated genomic errors were detected in 36.28% of our albino patients and seventy one multiple mutant genomic errors were defined among relatives of thirty seven index families of oculocutaneous albinism patients. To the best of our knowledge, this preliminary study is the first report of its kind from Egypt. The high rate of parental consanguinity among the parents of our Egyptian albino patients may account for the frequency of this genodermatosis in Egypt

unique albino village of bhatti tribe in rural Sindh, Pakistan, with oculocutaneous albinism manifestations: an epidemiological study

Oculocutaneous albinism is a disease with an autosomal recessive inheritance pattern in most cases. People with Oculocutaneous albinism face many health, psychological and financial issues. In this study, we report a unique village of Bhatti tribe in Jacobabad District, Pakistan, in which 40 children and adults with albinism live. The aim of this study was to observe the pattern of inheritance, complications and socioeconomic impacts of this condition on the community. Detailed clinical history and relevant data were recorded on a specially designed performa followed by clinical examination by a consultant dermatologist together with his team to observe the extent of the disease and associated complications in two seasons [winter and summer]. This village, with a total population of 810, had 40 cases, 17 male and 23 female, ranging in age from 6 months to 35 years. About 65% of the affected individuals were younger than 16 years of age. There were 22 involved families in this village and 2 of them had 3 or 4 affected members. In this area, which is geographically close to the equator, all 40 cases [100%] had photodermatosis and 36/40 cases [90%] had bacterial skin infections during summer. In addition, they had limited outdoor exposure during this season. These complications also caused occupational, social and educational limitations 9 months a year. Eye problems were present in all 40 cases; however, all 40 cases were malignancy free. Oculocutaneous albinism is challenging not only because of its management but also because of its social and financial impacts. The current trend of consanguineous marriages, prevalent in this village, puts further emphasis on the role and the importance of marriage counseling in such situations

Posibles vertientes del gene del síndrome de Hermansky-Pudlak en Puerto Rico / Possible origins of the gene of Hermansky-Pudlak in Puerto Rico

Five out of six albino persons in Puerto Rico suffer from the Hermansky-Pudlak syndrome. This syndrome has been reported also in other countries such as Great Britain, the Netherlands, Belgium, and Mexico, among others. Due to the geographical isolation of the island it is likely that these patients share a common ancestor. In explaining how the gene may have arrived to Puerto Rico the following possibilities are considered: (1) British soldiers attacking the island since 1595. (2) Dutch attackers in 1625. (3) aboriginal tribes. (4) slave traders

Albinism and Hermansky-Pudlak syndrome in Puerto Rico

Five types of oculocutaneous albinism and two types of ocular albinism were found among 349 Puerto Rican albinos. The most prevalent type of albinism was the Hermansky-Pudlak syndrome (HPS). HPS was observed in five of every six albinos in Puerto Rico. The prevalence of HPS was highest in the northwestern quarter of the island, affecting approximately one in 1,800 persons, and approximately one in 22 are carriers of the gene. HPS is an autosomal recessively inherited triad of a tyrosinase-positive type of albinism, a hemorrhagic diathesis due to storage pool deficient platelets and accumulation of ceroid in tissues. The pigmentary phenotype of HPS albinos resembled that of any other type of oculocutaneous or ocular albinism. The most reliable method of diagnosing HPS is by a deficiency of platelet dense bodies observed by electron microscopy. The accumulation of ceroid in the tissues is associated with fibrotic restrictive lung disease and granulomatous enteropathic disease. The enteropathic disorder resembles Crohn's disease and with few exceptions, had its onset after 13 years of age. The major causes of death were fibrotic restrictive pulmonary disease, hemorrhagic episodes and sequelae of granulomatous enteropathic disease. Menometrorrhagia was common in women with HPS. No immune deficiency was found in HPS patients. The majority of patients with HPS had visal acuities of 20/200 or worse and consequently were legally blind. Albinos of all types, including HPS, lacked binocular...