Mutations affecting pigmentation in man: I. Neuroectodermal melanolysosomal disease

Discerning clinicopathological features of congenital neutropenia syndromes: an approach to diagnostically challenging differential diagnoses

The congenital neutropenia syndromes are rare haematological conditions defined by impaired myeloid precursor differentiation or function. Patients are prone to severe infections with high mortality rates in early life. While some patients benefit from granulocyte colony-stimulating factor treatment, they may still face an increased risk of bone marrow failure, myelodysplastic syndrome and acute leukaemia. Accurate diagnosis is crucial for improved outcomes; however, diagnosis depends on familiarity with a heterogeneous group of rare disorders that remain incompletely characterised. The clinical and pathological overlap between reactive conditions, primary and congenital neutropenias, bone marrow failure, and myelodysplastic syndromes further clouds diagnostic clarity.We review the diagnostically useful clinicopathological and morphological features of reactive causes of neutropenia and the most common primary neutropenia disorders: constitutional/benign ethnic neutropenia, chronic idiopathic neutropenia, cyclic neutropenia, severe congenital neutropenia (due to mutations in ELANE, GFI1, HAX1, G6PC3, VPS45, JAGN1, CSF3R, SRP54, CLPB and WAS), GATA2 deficiency, Warts, hypogammaglobulinaemia, infections and myelokathexis syndrome, Shwachman-Diamond Syndrome, the lysosomal storage disorders with neutropenia: Chediak-Higashi, Hermansky-Pudlak, and Griscelli syndromes, Cohen, and Barth syndromes. We also detail characteristic cytogenetic and molecular factors at diagnosis and in progression to myelodysplastic syndrome/leukaemia.

Diagnostic and therapeutic caveats in Griscelli syndrome

Griscelli syndrome (GS) is a rare autosomal recessive disease with characteristic pigment distribution, and there are currently 3 types according to the underlying genetic defect and clinical features. We present the case of a girl born from consanguineous parents who presented with predominant neurologic symptoms, silvery hair and granulomatous skin lesions. Cerebral magnetic resonance revealed diffuse white matter lesions, and central nervous system (CNS) lymphocytic infiltration was suspected. The patient underwent haematopoietic stem cell transplantation with graft failure and autologous reconstitution. She developed elevated liver enzyme with a cholestatic pattern. Multiple liver biopsies revealed centrilobular cholestasis and unspecific portal inflammation that improved with immunomodulatory treatment. She was revealed to have an impaired cytotoxicity in NK cells and a decreased expression of RAB27A. However, no variants were found in the gene. All types of GS present with pigment dilution and irregular pigment clumps that can be seen through light microscopy in hair and skin biopsy. Dermic granulomas and immunodeficiency with infectious and HLH predisposition have been described in GS type 2 (GS2). Neurologic alterations might be seen in GS type 1 (GS1) and GS type 2 (GS2), due to different mechanisms. GS1 presents with neurologic impairment secondary to myosin Va role in neuronal development and synapsis. Meanwhile, GS2 can present with neurologic impairment secondary to SNC HLH. Clinical features and cytotoxicity might aid in differentiating GS1 and GS2, especially since treatment differs.

Myosin Va Brain-Specific Mutation Alters Mouse Behavior and Disrupts Hippocampal Synapses

Myosin Va (MyoVa) is a plus-end filamentous-actin motor protein that is highly and broadly expressed in the vertebrate body, including in the nervous system. In excitatory neurons, MyoVa transports cargo toward the tip of the dendritic spine, where the postsynaptic density (PSD) is formed and maintained. MyoVa mutations in humans cause neurologic dysfunction, intellectual disability, hypomelanation, and death in infancy or childhood. Here, we characterize the Flailer (Flr) mutant mouse, which is homozygous for a myo5a mutation that drives high levels of mutant MyoVa (Flr protein) specifically in the CNS. Flr protein functions as a dominant-negative MyoVa, sequestering cargo and blocking its transport to the PSD. Flr mice have early seizures and mild ataxia but mature and breed normally. Flr mice display several abnormal behaviors known to be associated with brain regions that show high expression of Flr protein. Flr mice are defective in the transport of synaptic components to the PSD and in mGluR-dependent long-term depression (LTD) and have a reduced number of mature dendritic spines. The synaptic and behavioral abnormalities of Flr mice result in anxiety and memory deficits similar to that of other mouse mutants with obsessive-compulsive disorder and autism spectrum disorder (ASD). Because of the dominant-negative nature of the Flr protein, the Flr mouse offers a powerful system for the analysis of how the disruption of synaptic transport and lack of LTD can alter synaptic function, development and wiring of the brain and result in symptoms that characterize many neuropsychiatric disorders.

Myosin Va interacts with the exosomal protein spermine synthase

Myosin Va (MyoVa) is an actin-based molecular motor that plays key roles in the final stages of secretory pathways, including neurotransmitter release. Several studies have addressed how MyoVa coordinates the trafficking of secretory vesicles, but why this molecular motor is found in exosomes is still unclear. In this work, using a yeast two-hybrid screening system, we identified the direct interaction between the globular tail domain (GTD) of MyoVa and four protein components of exosomes: the WD repeat-containing protein 48 (WDR48), the cold shock domain-containing protein E1 (CSDE1), the tandem C2 domain-containing protein 1 (TC2N), and the enzyme spermine synthase (SMS). The interaction between the GTD of MyoVa and SMS was further validated in vitro and displayed a K_d in the low micromolar range (3.5 ± 0.5 µM). SMS localized together with MyoVa in cytoplasmic vesicles of breast cancer MCF-7 and neuroblastoma SH-SY5Y cell lines, known to produce exosomes. Moreover, MYO5A knockdown decreased the expression of SMS gene and rendered the distribution of SMS protein diffuse, supporting a role for MyoVa in SMS expression and targeting.

Oculocerebral hypopigmentation syndrome maps to chromosome 3q27.1q29

BACKGROUND

In 1967, Cross et al. [J Pediatr 1967;70:398-406] reported four siblings with intellectual disability, microcephaly, neurologic and ocular disorders, and hypopigmentation involving skin and hair. This novel entity, known as oculocerebral hypopigmentation syndrome (OCHS) or Cross syndrome (OMIM 257800), is assumed to be autosomal recessive. However, its genetic cause is still unknown.

CASE REPORT

A 4-year-old girl is reported with OCHS, a history of recurrent infections and vertebral fusion of L4-L5. Central nervous system and cardiac imaging as well as metabolic screening were normal. Microscopic hair investigations did not show any melanin deposit defects.

RESULTS

Using molecular cytogenetics, we detected a de novo interstitial del(3)(q27.1q29) of the paternal chromosome. To our knowledge, this is the first molecular genetics finding in a patient with OCHS. Here we discuss the genotype-phenotype correlations and suggest candidate genes for this disorder.

CONCLUSION

Investigating further patients would enable fine-mapping the OCHS locus and identifying its putative gene.

The role of myosin V in exocytosis and synaptic plasticity

In neuroscience, myosin V motor proteins have attracted attention since they are highly expressed in brain, and absence of myosin Va in man leads to a severe neurological disease called Griscelli syndrome. While in some cells myosin V is described to act as a vesicle transport motor, an additional role in exocytosis has emerged recently. In neurons, myosin V has been linked to exocytosis of secretory vesicles and recycling endosomes. Through these functions, it is implied in regulating important brain functions including the release of neuropeptides by exocytosis of large dense-core vesicles and the insertion of neurotransmitter receptors into post-synaptic membranes. This review focuses on the role of myosin V in (i) axonal transport and stimulated exocytosis of large dense-core vesicles to regulate the secretion of neuroactive substances, (ii) tethering of the endoplasmic reticulum at cerebellar synapses to permit long-term depression, (iii) recycling of α-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptors at hippocampal synapses during long-term potentiation, and (iv) recycling of nicotinic acetylcholine receptors at the neuromuscular junction. Myosin V is thus discussed as an important modulator of synaptic plasticity.

Oculocutaneous albinism associated with multiple malformations and psychomotor retardation

We present a case of oculocutaneous albinism in a child associating multiple malformations (preaxial polydactyly, small penis, cardiac malformation) and psychomotor retardation. To our knowledge, this association has not been previously described.

Griscelli syndrome: description of a case with Rab27A mutation

A 7-month-old Turkish boy presented with partial albinism and typical clinical features of an accelerated phase, suggesting the diagnosis of Griscelli syndrome. The diagnosis was confirmed by light microscopic evaluation of hair and a peripheral blood smear. Genetic analysis identified a mutation in the Rab27A gene. He was initiated immunosuppressive treatment but accelerated phase could not be ameliorated. He unfortunately died from multiorgan failure. The finding of partial albinism in children should alert clinicians to consider Griscelli syndrome since simple methods can confirm the diagnosis and early diagnosis is life-saving.

Primary hemophagocytic syndromes point to a direct link between lymphocyte cytotoxicity and homeostasis

Hemophagocytic syndrome (HS) is a severe and often fatal syndrome resulting from potent and uncontrolled activation and proliferation of T-lymphocytes, leading to excessive macrophage activation and multiple deleterious effects. The onset of HS characterizes several inherited disorders in humans. In each condition, the molecular defect impairs the granule-dependent cytotoxic activity of lymphocytes, thus highlighting the determinant role of this function in driving the immune system to a state of equilibrium following infection. It has also been shown that some of the proteins required for lytic granule secretion are required for melanocyte function, leading to associated hypopigmentation in these conditions. This review focuses on several effectors of this secretory pathway, recently identified, because their defects cause these disorders, and discusses their role and molecular interactions in granule-dependent cytotoxic activity.

Myosin Va is required for normal photoreceptor synaptic activity

Myosin Va is an actin-based motor molecule, one of a large family of unconventional myosins. In humans, mutations in MYO5A cause Griscelli syndrome type 1 and Elejalde syndrome, diseases characterized by pigmentation defects and the prepubescent onset of severe neurological deficits that ultimately lead to a shortened lifespan. Mutations in the Myo5a gene in mouse cause the dilute series of mouse mutants, demonstrating that myosin Va is involved in pigmentation and neural function. Although the reason for the pigmentation abnormalities is well understood, the role of myosin Va in neural function is not. Myosin Va has been found in synaptic terminals in the retina and brain. We report here new physiological evidence for a role of myosin Va in synaptic function. Photoreceptor synapses in neurologically affected myosin Va mutant mice have both anatomical and physiological abnormalities. Thus, myosin Va is required for normal photoreceptor signalling, suggesting that it might function in central nervous system synapses in general, with aberrant synaptic activity potentially underlying the neurological defects observed in dilute lethal mice and patients with Griscelli syndrome type 1 and Elejalde syndrome.

Griscelli syndrome without hemophagocytosis in an eleven-year-old girl: expanding the phenotypic spectrum of Rab27A mutations in humans

We present an eleven-year-old female patient who was referred to us with silvery hair, hepatosplenomegaly, neutropenia-thrombocytopenia, hypogammaglobulinemia and degenerative white matter disease, with a family history of a female sibling dying at the age of five and two living male cousins, ages 10 and 11. She had been followed up for her cytopenia the last three years and had totally recovered from a hemiplegic episode before admission. The family was of Arabic origin, and a second-degree consanguinity was reported between the parents. Microscopic analysis of her hair shafts revealed irregularly distributed small and large clumps of melanin, and skin biopsy findings were consistent with partial albinism. Bone marrow aspiration and biopsy did not detect any evidence of hemophagocytosis. Genetic analysis identified a homozygous two-base-pair deletion (51 del CT leading to S18X) in the Rab27A gene of the patient. She suffered from febrile neutropenic episodes. Her persistent cytopenia could not be corrected with immunoglobulin, thrombocyte infusions, or a short course of growth factor treatment. Splenectomy was planned due to her progressive splenic enlargement. She was also considered for bone marrow transplantation. She unfortunately died from an intracranial hemorrhage. Her clinical presentation was remarkable, mostly resembling partial albinism immunodeficiency/Elejalde syndrome due to her older age and absence of hemophagocytosis, but with molecular findings confirming Griscelli syndrome.

Hermansky-Pudlak syndrome: vesicle formation from yeast to man

The disorders known as Hermansky-Pudlak syndrome (HPS) are a group of genetic diseases resulting from abnormal formation of intracellular vesicles. In HPS, dysfunction of melanosomes results in oculocutaneous albinism, and absence of platelet dense bodies causes a bleeding diathesis. In addition, some HPS patients suffer granulomatous colitis or fatal pulmonary fibrosis, perhaps due to mistrafficking of a subset of lysosomes. The impaired function of specific organelles indicates that the causative genes encode proteins operative in the formation of certain vesicles. Four such genes, HPS1, ADTB3A, HPS3, and HPS4, are associated with the four known subtypes of HPS, i.e. HPS-1, HPS-2, HPS-3, and HPS-4. ADTB3A codes for the beta 3 A subunit of adaptor complex-3, known to assist in vesicle formation from the trans-Golgi network or late endosome. However, the functions of the HPS1, HPS3, and HPS4 gene products remain unknown. These three genes arose with the evolution of mammals and have no homologs in yeast, reflecting their specialized function. In contrast, all four known HPS-causing genes have homologs in mice, a species with 14 different models of HPS, i.e. hypopigmentation and a platelet storage pool deficiency. Pursuit of the mechanism of mammalian vesicle formation and trafficking, impaired in HPS, relies upon investigation of these mouse models as well as studies of protein complexes involved in yeast vacuole formation.

Evidence that Griscelli syndrome with neurological involvement is caused by mutations in RAB27A, not MYO5A

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 disease: genotype-phenotype correlation in an array of clinical heterogeneity

Griscelli disease is a rare autosomal recessive disorder characterized by diffuse pigmentary dilution and occurrence of acute phases of uncontrolled lymphocyte and macrophage activation, so-called "hemophagocytic syndrome" (HS) that leads to death. Recently, two closely linked genes located on human 15q21 region have been found to be responsible for the disease. We present clinical and laboratory findings of 13 unrelated patients with Griscelli disease as well as mutation analyses in an effort to define a genotype-phenotype correlation. Eight patients who showed RAB27A mutations presented with HS. In contrast, two patients who primarily presented with a neurological impairment in the absence of infection susceptibility or HS were found to have homozygous MYO5A mutations. No mutation in RAB27A could be detected in the other three patients. One of the latter developed HS at a rather late age, while the other two are free of HS at 12 and 15 years of age. Griscelli disease presents with a heterogeneous clinical picture that seems to reflect the involved gene defect. This genotype-phenotype correlation suggests that the natural course of the disease and outcome is dictated by the site and type of the genetic mutation.

12-year-old male with Elejalde syndrome (neuroectodermal melanolysosomal disease)

Neuroectodermal melanolysosomal disease, also known as Elejalde syndrome, is a rare syndrome characterized by silvery hair, pigment abnormalities, and profound central nervous system dysfunction. It is similar to the Chediak-Higashi and Griscelli syndromes, although these syndromes are associated with severe immunologic dysfunction. We report on a 12-year-old male with Elejalde syndrome and compare the Elejalde, Chediak-Higashi, and Griscelli syndromes.

Hermansky-Pudlak syndrome and related disorders of organelle formation

Hermansky-Pudlak syndrome (HPS) consists of a group of genetically heterogeneous disorders which share the clinical findings of oculocutaneous albinism, a platelet storage pool deficiency, and some degree of ceroid lipofuscinosis. Related diseases share some of these findings and may exhibit other symptoms and signs but the underlying defect in the entire group of disorders involves defective intracellular vesicle formation, transport or fusion. Two HPS-causing genes, HPS1 and ADTB3A, have been isolated but the function of only the latter has been determined. ADTB3A codes for the beta 3A subunit of adaptor complex-3, responsible for vesicle formation from the trans-Golgi network (TGN). The many HPS patients who do not have HPS1 or ADTB3A mutations have their disease because of mutations in other genes. Candidates for these HPS-causing genes include those responsible for mouse models of HPS or for the 'granule' group of eye color genes in Drosophila. Each gene responsible for a subset of HPS or a related disorder codes for a protein which almost certainly plays a pivotal role in vesicular trafficking, inextricably linking clinical and cell biological interests in this group of diseases.

Mutations in RAB27A cause Griscelli syndrome associated with haemophagocytic syndrome

Griscelli syndrome (GS, MIM 214450), a rare, autosomal recessive disorder, results in pigmentary dilution of the skin and the hair, the presence of large clumps of pigment in hair shafts and an accumulation of melanosomes in melanocytes. Most patients also develop an uncontrolled T-lymphocyte and macrophage activation syndrome (known as haemophagocytic syndrome, HS), leading to death in the absence of bone-marrow transplantation. In contrast, early in life some GS patients show a severe neurological impairment without apparent immune abnormalities. We previously mapped the GS locus to chromosome 15q21 and found a mutation in a gene (MYO5A) encoding a molecular motor in two patients. Further linkage analysis suggested a second gene associated with GS was in the same chromosomal region. Homozygosity mapping in additional families narrowed the candidate region to a 3.1-cM interval between D15S1003 and D15S962. We detected mutations in RAB27A, which lies within this interval, in 16 patients with GS. Unlike MYO5A, the GTP-binding protein RAB27A appears to be involved in the control of the immune system, as all patients with RAB27A mutations, but none with the MYO5A mutation, developed HS. In addition, RAB27A-deficient T cells exhibited reduced cytotoxicity and cytolytic granule exocytosis, whereas MYO5A-defective T cells did not. RAB27A appears to be a key effector of cytotoxic granule exocytosis, a pathway essential for immune homeostasis.

Two genes are responsible for Griscelli syndrome at the same 15q21 locus

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.

Molecular genetic dissection of mouse unconventional myosin-VA: tail region mutations

We used an RT-PCR-based sequencing approach to identify the mutations responsible for 17 viable dilute alleles, a mouse-coat-color locus encoding unconventional myosin-VA. Ten of the mutations mapped to the MyoVA tail and are reported here. These mutations represent the first extensive collection of tail mutations reported for any unconventional mammalian myosin. They identify sequences important for tail function and identify domains potentially involved in cargo binding and/or proper folding of the MyoVA tail. Our results also provide support for the notion that different myosin tail isoforms produced by alternative splicing encode important cell-type-specific functions.

Partial albinism with immunodeficiency: Griscelli syndrome: report of a case and review of the literature

Partial albinism with immunodeficiency (Griscelli syndrome) is an uncommon disorder characterized by pigmentary dilution and variable immunodeficiency. Features include a silvery-gray sheen to the hair, large clumped melanosomes in hair shafts, and prominent mature melanosomes in cutaneous melanocytes with sparse pigmentation of adjacent keratinocytes. Immunologic abnormalities most often include impaired natural killer cell activity, absent delayed-type hypersensitivity, and impaired responses to mitogens. Impaired helper T cell function and hypogammaglobulinemia have also been described. The syndrome can be differentiated from Chediak-Higashi syndrome by pathognomonic light and electron microscopic features in skin and hair, and absence of consistent granulocyte abnormalities, but similarly carries a poor prognosis without bone marrow transplantation. We describe a patient with Griscelli syndrome who presented with hepatosplenomegaly, hepatitis, pancytopenia, and silvery hair in the newborn period.

Human herpesvirus-6 (HHV-6)-associated necrotizing encephalitis in Griscelli's syndrome

We report a male caucasian German pediatric patient of no Arab or Mediterranean ancestry with virus associated CNS lesions in Griscelli's syndrome (GS; McKusick No. 214450). The boy presented with recurrent infections, and meningitis with subsequent progressive signs of increased intracranial pressure leading to death at 32 weeks of age. At autopsy, various sites of the CNS revealed necroses in gray and white matter. CNS histology revealed numerous and massive predominantly perivascular CD8 positive lymphohistiocytic infiltrates. These findings were associated strictly with the presence of human herpesvirus-6 (HHV-6) genome or the HHV-6 specific late antigen H-AR 3, found in neurons, oligodendrocytes, and astrocytes. The search for HHV-6 replication dependent antigen, HHV-7 DNA, CMV, adenovirus, Coxsackie B1, B2, and B4-antigens, and mycobacteria was not successful. Detection of viruses was attempted using immunohistochemistry, in situ hybridization or nested polymerase chain reaction, respectively. Lymphocyte typing was carried out immunohistochemically. In GS, virus induced CNS damage does not seem to require necessarily active virus replication. It may also appear as a consequence of an immune reaction triggered by antigen expression.

Griscelli disease maps to chromosome 15q21 and is associated with mutations in the myosin-Va gene

Griscelli disease (OMIM 214450) is a rare autosomal recessive disorder characterized by pigmentary dilution, variable cellular immunodeficiency and onset of acute phases of uncontrolled lymphocyte and macrophage activation, leading to death in the absence of bone-marrow transplantation. The pigmentary dilution is characterized by a diffuse skin pigmentation, silvery hair, large clumps of pigments in the hair shafts (Fig. 1) and an accumulation of melanosomes in melanocytes, with abnormal transfer of the melanin granules to the keratinocytes. Immunological abnormalities are characterized by absent delayed-type cutaneous hypersensitivity and an impaired natural-killer cell function. A similar disorder has been described in the dilute lethal mouse--which, however, differs by the occurrence of a severe neurological disorder. The dilute locus encodes myosin-Va, a member of the unconventional myosin family. Myosins bind actin and produce mechanical force through ATP hydrolysis. Some members of this family are thought to participate in organelle-transport machinery. Because of the phenotype resulting in the dilute mouse and because of their potential role in intracellular transport, unconventional myosin-encoding genes were regarded as candidate genes for Griscelli disease. Here we report that the Griscelli disease locus co-localizes on chromosome 15q21 with the myosin-Va gene, MYO5a, and that mutations of this gene occur in two patients with the disease. Griscelli disease is therefore a human equivalent of dilute expression in the mouse.

A new case of oculocerebral hypopigmentation syndrome (Cross syndrome) with additional findings

Cross syndrome is a rare syndrome characterized by ocular and cutaneous hypopigmentation and neurological manifestations. A few reports have been published since 1967. In this report, we present a new case of Cross syndrome with additional findings such as urinary tract abnormality, bilateral inguinal hernia, focal interventricular septal hypertrophy of the heart and vacuolization of myeloid series cells and distinct ultrastructural features of the skin.

Partial albinism with immunodeficiency (Griscelli syndrome)

Partial albinism with immunodeficiency is a rare and fatal immunologic disorder characterized by pigmentary dilution and variable cellular immunodeficiency. To define the phenotype, therapy, and outcome, we retrospectively analyzed seven consecutive patients. Primary abnormalities included a silvery-grayish sheen to the hair, large pigment agglomerations in hair shafts, and an abundance of mature melanosomes in melanocytes, with reduced pigmentation of adjacent keratinocytes. Clinical onset occurred between the ages of 4 months and 4 years and was characterized by accelerated phases (lymphohistiocytic infiltration of multiple organs, including the brain and the meninges), triggered by viral and bacterial infections. Characteristic laboratory features included pancytopenia, hypofibrinogenemia, hypertriglyceridemia, and hypoproteinemia. Consistent immunologic abnormalities were characterized by absent delayed-type cutaneous hypersensitivity and impaired natural killer cell function. Some patients had secondary hypogammaglobulinemia, impaired major histocompatibility complex-mediated cytotoxic effects, a decreased capacity of lymphocytes to trigger a mixed lymphocyte reaction, or various functional granulocytic abnormalities. The disease seems to be invariably lethal without bone marrow transplantation; the mean age at the time of death was 5 years. Bone marrow transplantation has been performed in three cases; two patients died in the immediate posttransplantation period of infectious complications, but one patient is cured after a follow-up of 5 years. We conclude that partial albinism with immunodeficiency (Griscelli syndrome) can be differentiated from Chédiak-Higashi syndrome by pathognomonic histologic features. One of the underlying immunologic defects may be a defective function of natural killer cells, predisposing the patient to virus-associated hemophagocytic syndrome or accelerated phases. The prognosis is very poor unless early bone marrow transplantation is carried out.

A kindred with Griscelli disease: spectrum of neurological involvement

We report four members of a highly consanguineous family with silver-grey pigmentation of hair, two of whom had skin histology compatible with Griscelli disease. Unlike previously reported patients, they did not suffer from recurrent infections. In addition, there was a spectrum of neurological involvement varying from mild cognitive delay with a convulsive disorder in one patient, to a fatal degenerative course in three others. One patient developed a prolonged febrile illness with histological evidence of florid lymphoid hyperplasia.

Bone marrow transplantation (BMT) for the syndrome of pigmentary dilution and lymphohistiocytosis (Griscelli's syndrome)

We report the successful treatment of the syndrome of pigmentary dilution and immunodeficiency (Griscelli's syndrome) with allogeneic bone marrow transplantation. Griscelli's syndrome includes silvery hair, recurrent infections, hepatosplenomegaly, progressive neurologic deterioration, and lymphohistiocytosis and is uniformly fatal. We present a family in which four of seven children of consanguinous parents were affected. The affected children were all born with silvery hair. Microscopic examination of the hair showed large clumps of pigment in the hair shaft. Skin biopsy revealed an accumulation of melanosomes in the melanocytes. Three of the affected children were deceased before 20 months of age. Pathology of liver and lung in two of the siblings showed an infiltration of lymphocytes and histiocytes. Immunologic studies in one of these cases were notable for a decreased number of T cells and poor T-cell mitogen stimulation with concanavalin A (Con A) and pokeweed mitogen (PWM). Recently, a fourth sibling with silvery gray hair was referred to us at 3 months of age for evaluation. T-cell function studies were normal and she appeared in overall good health. Because of the expected fatal outcome, allogeneic bone marrow transplantation was performed at 4 months of age. Two years later the patient remains in excellent health. This suggests that cells of hematopoietic origin are responsible for the fatal outcome in Griscelli's syndrome and that bone marrow transplantation early in the course of the disease is an important modality for treatment of this syndrome.

An oculocerebral hypopigmentation syndrome: a case report with clinical, histochemical, and ultrastructural findings

A 4 year old boy is reported with tyrosinase positive hypopigmentation, mental retardation, ataxia, and myopia. Radiological investigation showed occipital cerebral atrophy, coxa valga, and generalised osteoporosis. The skin histology and electron microscopy are reported and discussed. The clinical features are similar to those of the oculocerebral hypopigmentation syndrome described by Preus et al.