Griscelli syndrome (GS) type II is a rare hereditary disorder characterized by partial albinism, immunodeficiency, and the subsequent development of hemophagocytic syndrome (HPS). Herein, we present a case involving a four-month-old infant admitted to our facility due to a prolonged fever complicated by HPS. The diagnosis of GS type 2 was established based on a constellation of clinical and laboratory findings: consanguinity, familial history of early infectious fatalities, ocular-cutaneous hypopigmentation, characteristic silvery hair sheen, onset of HPS, and notably, the pathognomonic appearance upon microscopic examination of a hair sample. The absence of giant granules within nucleated cells helped exclude Chediak-Higashi syndrome.

Griscelli syndrome (GS) is a rare autosomal recessive disorder, which has been classified into three subtypes based on clinical and genetic differences. GS subtype 2 is commonly associated with hemophagocytic lymphohistiocytosis (HLH) and recurrent infections due to immunodeficiency. In this study, we describe a four-month-old boy with genetically proven GS2, with neurological and immunological manifestations. He presented with fever, refusal of feeds, drowsiness, and multiple episodes of seizures. Examination revealed hypopigmented skin, silvery gray hair, and organomegaly. The child developed features of HLH, fulfilling clinical and laboratory criteria. Neuroimaging findings were in concordance with HLH of the central nervous system. Microscopic examination of the hair showed clumps of melanin pigment along the hair shaft. All findings were in favor of GS type 2, complicated with HLH, which was later confirmed with a homozygous deletion of the RAB27A gene on exome sequencing. Unfortunately, the baby succumbed to death due to severe sepsis and multiorgan dysfunction. The silvery gray hair, with typical hair microscopic findings, and association with HLH are strong indicators for this potentially fatal condition and aid in prompt diagnosis and initiation of treatment. Hematopoietic stem cell transplantation is the only lifesaving treatment option.

Griscelli syndrome is a rare inherited autosomal recessive syndrome that causes immunodeficiency. Hemophagocytic lymphohistiocytosis (HLH), which is characterized by a high mortality rate, may develop because of Griscelli syndrome type 2 (GS2). We aimed to share our experience with the diagnosis and treatment methods of patients who developed HLH secondary to GS2. Patients with GS2 who were diagnosed and treated for HLH between 2017 and 2022 at the Cukurova University Division of Pediatric Allergy & Immunology and Division of Pediatric Hematology were included in the study. Microscopic examination of the hair shaft and next-generation sequencing for molecular genetic testing of RAB27A helped in the diagnosis of GS2. The first clinical presentation of 8 patients was HLH. One patient presented with CNS involvement and two patients presented with recurrent fever. Over 5 years, GS2 was diagnosed in 15 patients, of whom 11 (73.3%) developed HLH. The HLH-2004 protocol was used to treat these patients. Hematopoietic stem cell transplantation (HSCT) was performed in five patients who were matched with suitable donors. While all patients who underwent HSCT were alive, three patients who could not undergo HSCT because no donor could be found died. Deletion of CAAGC at nucleotides 514_518 in GS2 patients is associated with CNS involvement and a poor prognosis. HLH may be the first sign of presentation in patients with GS2. Although further research is needed, regardless of the conditioning regimen utilized, early HSCT remains the primary therapy option for preventing GS2-induced mortality in HLH.

Griscelli syndrome type 2 (GS2) is a rare, autosomal recessive condition caused by a mutation of the RAB27A gene that causes primary immunodeficiency and pigmentary dilution of skin and hair. It is a rare occurrence, with only 160 cases reported all over the world. It commonly progresses to hemophagocytic lymphohistiocytosis (HLH) due to immunodeficiency. We herein represent the case of a seven-month-old male child, the firstborn of a third-degree consanguineous marriage, who presented with recurrent viral infections and silvery grey hair. A definitive diagnosis of GS 2 was made in accordance with the pathognomonic appearance of hair on microscopic examination and whole genome sequencing, which revealed a homozygous missense mutation in exon 3 of the RAB27A gene. This article is being reported to highlight the rare incidence of this disease, its overlapping clinical features with malnutrition, the challenges faced in diagnosis, and the treatment modalities for it.

Griscelli syndrome type 2 (GS2) is an autosomal recessive immunodeficiency characterized by hair hypopigmentation, recurrent fever, hepatosplenomegaly and pancytopenia. This study aims to find new genetic changes and clinical features in 18 children with GS2 caused by the RAB27A gene defect. In all, 18 Iranian children with GS2 who presented with silver grey hair and frequent pyogenic infection were included in this study. After recording demographic and clinical data, PCR sequencing of the RAB27A gene was performed for all exons and exon-intron boundaries. Two patients in this study were subjected to whole-exome sequencing followed by Sanger sequencing. Light microscopy study of hair showed large irregular clumps of pigment with the absence of giant granules on the blood smear. Mutation analysis of the RAB27A gene identified two novel missense mutations as homozygous in a patient, one in exon 2, c.140G>C and another in exon 4, c.328G>T. In addition, for 17 other patients, 6 reported mutations were obtained including c.514_518delCAAGC, c.150_151delAGinsC, c.400_401delAA, c.340delA, c.428T>C and c.221A>G. The mutation c.514_518delCAAGC was the most frequent and found in 10 patients; this mutation may be considered a hotspot in Iran. Early diagnosis and treatment of RAB27A deficiency can contribute to better disease outcomes. In affected families, genetic results could be urgently needed to make a timely decision about haematopoietic stem cell transplantation and prenatal diagnosis.

UNASSIGNED: Griscelli syndrome (GS) is a very rare autosomal recessive disorder, belongs to group of \"silvery hair syndromes\" which includes Chediak-Higashi syndrome (CHS) and Elejalde syndrome. Hair light microscopy helps in the differentiation of GS and CHS, as both manifest with clinical features. Trichoscopy is useful in the diagnosis of many hair shaft disorders. Here, authors describe the trichoscopic features of GS in skin of color.
UNASSIGNED: This was an observational study conducted in a private dermatology clinic and in a tertiary care hospital. A total of 5 cases of suspected GS were referred by pediatrician. Consent was obtained. The demographic data in terms of age, gender, consanguinity, and clinical history was documented. Trichoscopic examination was performed with FotoFinder videodermoscope with 20× magnification, the clinical images were captured with Medicam 1000. Trichoscopy showed large and irregular pigment clumps in 4 cases. One case demonstrated hypopigmentation of hair without pigment clumps [Figure 3a].
UNASSIGNED: Trichoscopy showed large and irregular pigment clumps in 4 cases. One case demonstrated hypopigmentation of hair without pigment clumps.
UNASSIGNED: Trichoscopy shows characteristic features GS. It is a useful method when facility for light or polarized microscope is unavailable.

Griscelli syndrome type 1 (GS1) is a rare inherited autosomal recessive disease caused by a deleterious variant in the MYO5A gene and characterized by general hypopigmentation, neurological symptoms, motor disability, hypotonia, and vision abnormality. Only nine pathogenic variants in the MYO5A gene have been confirmed in association with the GS1. All of the reported pathogenic variants are truncating. Herein, two siblings from a consanguineous Iranian family with abnormal pigmentation and neurological symptoms were referred for genetic counseling. Whole-exome sequencing (WES) revealed a novel homozygous truncating variant c.1633_1634delAA (p.Asn545Glnfs*10) in the MYO5A gene, which was completely co-segregated with the phenotype in all affected and unaffected family members. Computational analysis and protein modeling demonstrated the deleterious effects of this variant on the structure and function of the protein. The variant, according to ACMG guidelines, was classified as pathogenic. Besides the novelty of the identified variant, our patients manifested more severe clinical symptoms and presented distal hyperlaxity in all four limbs, which was a new finding. In conclusion, we expanded the mutational and phenotypic spectrum of the GS1. Moreover, by studying clinical manifestations in all molecularly confirmed reported cases, provided a comprehensive overview of clinical presentation, and attempted to find a genotype-phenotype correlation.

Hair microscopy is a fast and effortless diagnostic method for many diseases affecting hair in daily practice. Many diseases can present with hair shaft disorders in pediatric neurology practice.
Children with pathological hair findings were included in our study. Microscopic evaluation of the hair was performed under light microscopy. The clinical findings, pathological hair shaft findings, laboratory tests, and final diagnosis of the patients were evaluated.
In our study, 16 patients with rare pathological hair findings were identified. Of these 16 patients, nine were diagnosed with giant axonal neuropathy, three with Griscelli syndrome, two with Menkes disease, and two with autosomal recessive woolly hair disease. In hair inspection, curly and tangled hair in patients with giant axonal neuropathy; silvery blond hair in patients with Griscelli syndrome; sparse, coarse, and light-colored hair in patients with Menkes disease; and hypotrichosis in patients with autosomal recessive woolly hair were remarkable findings. Dystrophic hair was detected in most of the patients on light microscopy. In addition, signs of trichorrhexis nodosa, tricoptylosis, and pili torti were found. In particular, pigment deposition in the hair shaft of two patients diagnosed with Griscelli syndrome and pili torti findings in two patients with Menkes disease were the most important findings suggestingthe diagnosis.
Detection of hair findings in the physical examination and performing light microscopic evaluation facilitates the diagnosis of rare diseases accompanied by hair findings. A hair examination should be performed as a part of physical and neurological examinationson eachpatient regardless of thecomplaint.

Lysosome-related organelles (LROs) are a group of functionally diverse, cell type-specific compartments. LROs include melanosomes, alpha and dense granules, lytic granules, lamellar bodies and other compartments with distinct morphologies and functions allowing specialised and unique functions of their host cells. The formation, maturation and secretion of specific LROs are compromised in a number of hereditary rare multisystem disorders, including Hermansky-Pudlak syndromes, Griscelli syndrome and the Arthrogryposis, Renal dysfunction and Cholestasis syndrome. Each of these disorders impacts the function of several LROs, resulting in a variety of clinical features affecting systems such as immunity, neurophysiology and pigmentation. This has demonstrated the close relationship between LROs and led to the identification of conserved components required for LRO biogenesis and function. Here, we discuss aspects of this conserved machinery among LROs in relation to the heritable multisystem disorders they associate with, and present our current understanding of how dysfunctions in the proteins affected in the disease impact the formation, motility and ultimate secretion of LROs. Moreover, we have analysed the expression of the members of the CHEVI complex affected in Arthrogryposis, Renal dysfunction and Cholestasis syndrome, in different cell types, by collecting single cell RNA expression data from the human protein atlas. We propose a hypothesis describing how transcriptional regulation could constitute a mechanism that regulates the pleiotropic functions of proteins and their interacting partners in different LROs.

Griscelli syndrome (GS) is a rare genetic disorder that encompasses three different subtypes (GS type 1 (GS1), GS type 2 (GS2), and GS type 3 (GS3)), in which isolated neurological manifestations without immune system implications are typically seen in GS1, while neurological involvements in GS2 should be attributed to the macrophage and lymphocyte invasion of the central nervous system (CNS), under associated hemophagocytic lymphohistiocytosis (HLH). The presence of the clinical, biological, and hematologic features of HLH help explain the neurological defects that GS2 patients unusually present. In our case report, however, we attempt to highlight an uncommon presentation of GS2 involving a hemiparesis, along which we did not have any clinical or biological features of HLH. We also collect and evaluate similar published cases that feature this problem of explaining the neurological manifestations among GS2 patients.