Genetic analysis in three Egyptian patients with Griscelli syndrome Type 1 reveals new nonsense mutations in MYO5A (original) (raw)
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Two Genes Are Responsible for Griscelli Syndrome at the Same 15q21 Locus
Genomics, 2000
Griscelli syndrome is a rare autosomal recessive disease characterized by pigment dilution, variable cellular immunodeficiency, and an acute phase of uncontrolled T lymphocyte and macrophage activation. We previously mapped the disease locus to 15q21 and showed that a MyoVa gene (HGMW-approved symbol MYO5A) defect leads to Griscelli syndrome. We report a second MyoVa mutation in a new patient, confirming this first finding. However, in four other Griscelli syndrome patients analyzed, the MYOVA protein is expressed, and no mutation can be detected in the MyoVa gene coding sequence, even in the alternatively spliced region for which exon-intron boundaries were characterized. Linkage analysis performed in 15 Griscelli families thus far studied confirms the first localization. However, fine haplotype analysis in three families strongly suggests the existence of a second gene at the same locus for Griscelli syndrome less than 7.3 cM distant from the MyoVa gene.
The American Journal of Human Genetics, 2002
Griscelli syndrome (GS), a rare autosomal recessive disorder, is characterized by partial albinism, along with immunologic abnormalities or severe neurological impairment or both. Mutations in one of two different genes on chromosome 15q can cause the different subtypes of GS. Most patients with GS display the hemophagocytic syndrome and have mutations in RAB27A, which codes for a small GTPase. Two patients with neurological involvement have mutations in MYO5A, which codes for an actin-based molecular motor. The RAB27A and MYO5A gene products interact with each other and function in vesicle trafficking. We report the molecular basis of GS in a Muslim Arab kindred whose members have extremely variable neurological involvement, along with the hemophagocytic syndrome and immunologic abnormalities. The patients have normal MYO5A genes but exhibit a homozygous 67.5-kb deletion that eliminates RAB27A mRNA and immunocytofluorescence-detectable protein. We also describe the molecular organization of RAB27A and a multiplex polymerase chain reaction assay for the founder deletion in this kindred. Finally, we propose that all patients with GS have RAB27A mutations and immunologic abnormalities that sometimes result in secondary neurological involvement. The two patients described elsewhere who have MYO5A mutations and neurological complications but no immunologic defects may not have GS but instead may have Elejalde syndrome, a condition characterized by mild hypopigmentation and severe, primary neurological abnormalities.
Griscelli Syndrome Type 3: A Case Report from Kingdom of Saudi Arabia
Journal of Clinical Case Reports, 2016
Griscelli syndrome (GS) is a rare autosomal recessive disorder characterized by partial albinism. GS is a rare condition; its prevalence is unknown. Type 2 appears to be the most common of the three known types. The three different types of GS are caused by mutations in three different genes. Patients with GS type 1 have primary central nervous system dysfunction, resulting from mutations in the MYO5A gene. Type 2 patients commonly develop hemophagocytic. Lymphohistiocytosis, caused by mutations in the RAB27A gene, and type 3 have only partial albinism resulting from mutations in the MLPH. While hematopoietic stem cell transplantation is lifesaving in type 2, no specific therapy is required for types 1 and 3. Patients with GS types 1 and 3 are very rare. To date, 12 patients with similar presentation of GS-3 as our case have been reported. About 20 GS type 1 patients, including the patients described as Elejalde syndrome, have been reported. We report a 11 years old child with type 3 GS, referred to our clinic for partial albinism, healthy otherwise, having only pigmentary dilution; silvery gray hair, eye brows, and eyelashes. Though GS type 1 and 2 have been reported in the literature; however reports on GS type 3 from Saudi Arabia are very scanty. In communities with high incidence of consanguinity possibility of GS should be kept in mind.
Cellular and clinical report of new Griscelli syndrome type III cases
Pigment Cell & Melanoma Research, 2012
The RAB27A/Melanophilin/Myosin-5a tripartite protein complex is required for capturing mature melanosomes in the peripheral actin network of melanocytes for subsequent transfer to keratinocytes. Mutations in any one member of this tripartite complex cause three forms of Griscelli syndrome (GS), each with distinct clinical features but with a similar cellular phenotype. To date, only one case of GS type III (GSIII), caused by mutations in the Melanophilin (MLPH) gene, has been reported. Here we report seven new cases of GSIII in three distinct Arab pedigrees. All affected individuals carried a homozygous missense mutation (c.102C>T; p.R35W), located in the conserved Slp homology domain (SHD) of MLPH, and had hypomelanosis of the skin and hair. We report the first cellular studies on GSIII melanocytes, which demonstrated that MLPH(R35W) causes perinuclear aggregation of melanosomes in melanocytes, typical for GS. Additionally, co-immunoprecipitation assays showed that MLPH(R35W) lost its interaction with RAB27A, indicating pathogenicity of the R35W mutation.
Novel 47.5-kb deletion in RAB27A results in severe Griscelli Syndrome Type 2
Molecular Genetics and Metabolism, 2010
Griscelli syndrome (GS), a rare autosomal recessive disorder characterized by partial albinism and immunological impairment and/or severe neurological impairment, results from mutations in the MYO5A (GS1), RAB27A (GS2), or MLPH (GS3) genes. We identified a Hispanic patient born of a consanguineous union who presented with immunodeficiency, partial albinism, hepatic dysfunction, hemophagocytosis, neurological impairment, nystagmus, and silvery hair indicative of Griscelli syndrome type 2 (GS2). We screened for point mutations, but only exons 2-6 of the patient's DNA could be PCR-amplified. Whole genome analysis using the Illumina® 1M-Duo DNA Analysis BeadChip identified a homozygous deletion in the patient's DNA. The exact breakpoints of the 47.5-kb deletion were identified as chr15q15-q21.1: g.53332432_53379990del (NCBI Build 37.1); the patient lacks the promoter and 5'UTR regions of RAB27A, thus confirming the diagnosis of GS2.
Griscelli Syndrome Type 3: A Case Report
Journal of Medical Science And clinical Research, 2020
Griscelli syndrome (GS) is a rare autosomal recessive multisystem disorder of pigmentary dilution of skin, silver gray hair, variable immunodeficiency, neurological impairment and abnormal accumulation of melanosomes in melanocytes. The three different types of GS are caused by mutations in three different genes. Griscelli type 3 is due to mutations in the Mlph gene, characterized by hypomelanosis with no immunological and neurological manifestation. We report a 19 years old male with type 3 GS having only pigmentary dilution; silvery gray hair, eye brows, and eyelashes.
Brazilian Journal of Medical and Biological Research, 2008
Griscelli syndrome (GS) is a rare autosomal recessive disorder caused by mutation in the MYO5A (GS1, Elejalde), RAB27A (GS2) or MLPH (GS3) genes. Typical features of all three subtypes of this disease include pigmentary dilution of the hair and skin and silvery-gray hair. Whereas the GS3 phenotype is restricted to the pigmentation dysfunction, GS1 patients also show primary neurological impairment and GS2 patients have severe immunological deficiencies that lead to recurrent infections and hemophagocytic syndrome. We report here the diagnosis of GS2 in 3-year-old twin siblings, with silvery-gray hair, immunodeficiency, hepatosplenomegaly and secondary severe neurological symptoms that culminated in multiple organ failure and death. Light microscopy examination of the hair showed large, irregular clumps of pigments characteristic of GS. A homozygous nonsense mutation, C-T transition (c.550C>T), in the coding region of the RAB27A gene, which leads to a premature stop codon and prediction of a truncated protein (R184X), was found. In patient mononuclear cells, RAB27A mRNA levels were the same as in cells from the parents, but no protein was detected. In addition to the case report, we also present an updated summary on the exon/intron organization of the human RAB27A gene, a literature review of GS2 cases, and a complete list of the human mutations currently reported in this gene. Finally, we propose a flow chart to guide the early diagnosis of the GS subtypes and Chédiak-Higashi syndrome.
A Rare Case of Griscelli’s Syndrome with Review of Literature
Journal of evolution of medical and dental sciences, 2014
Griscelli syndrome is a rare autosomal recessive disorder characterized by partial albinism and immunodeficiency. The characteristic features include silver hair due to clumped melanosomes in hair shaft. Other features include hepatospleenomegaly, hepatitis, pancytopenia and immune abnormalities. CASE REPORT: A seven years old male child presented with partial albinic features and history of recurrent respiratory tract infection. The child had fever since 2months along with hepatospleenomegaly, pancytopenia and thrombocytopenic purpura. These rare clinical manifestations were diagnosed as GS which was confirmed by bone marrow biopsy and light microscopy of hair shaft. The mean patient age of survival is 5years. As early diagnosis can improve the outcome in such cases, a finding of partial albinism should alert the diagnosis of Griscelli's syndrome. CONCLUSION: We report a rare case of GS with characteristic manifestation surviving beyond the mean age of reported survival.