MYO5A Frameshift Variant in a Miniature Dachshund with Coat Color Dilution and Neurological Defects Resembling Human Griscelli Syndrome Type 1

A 1-month-old, female, smooth-haired miniature Dachshund with dilute color and neurological defects was investigated. The aim of this study was to characterize the clinical signs, histopathological changes and underlying genetic defect. The puppy had visible coat color dilution and was unable to hold its head on its own or to remain in a stable prone position for an extended period. Histopathological examination revealed an accumulation of clumped melanin and deposition of accumulated keratin within the hair follicles, accompanied by dermal pigmentary incontinence. These dermatological changes were compatible with the histopathology described in dogs with an MLPH-related dilute coat color. We sequenced the genome of the affected dog and compared the data to 795 control genomes. MYO5A, coding for myosin VA, was investigated as the top functional candidate gene. This search revealed a private homozygous frameshift variant in MYO5A, XM_022412522.1:c.4973_4974insA, predicted to truncate 269 amino acids (13.8%) of the wild type myosin VA protein, XP_022268230.1:p.(Asn1658Lysfs*28). The genotypes of the index family showed the expected co-segregation with the phenotype and the mutant allele was absent from 142 additionally genotyped, unrelated Dachshund dogs. MYO5A loss of function variants cause Griscelli type 1 syndrome in humans, lavender foal in horses and the phenotype of the dilute mouse mutant. Based on the available data, together with current knowledge on other species, we propose the identified MYO5A frameshift insertion as a candidate causative variant for the observed dermatological and neurological signs in the investigated dog.

Congenital Hypopigmentary Disorders with Multiorgan Impairment: A Case Report and an Overview on Gray Hair Syndromes

The term congenital hypopigmentary disorders refers to a wide group of heterogeneous hereditary diseases, clinically characterized by inborn pigmentary defects of the iris, hair, and/or skin. They include Gray Hair Syndromes (GHSs), a rare group of autosomal recessive genodermatosis hallmarked by inborn silvery gray hair. GHSs encompass Griscelli, Chediak⁻Higashi, Elejalde, and Cross syndromes, which are all characterized by a broad spectrum of severe multisystem disorders, including neurological, ocular, skeletal, and immune system impairment. In this manuscript, we describe in detail the clinical, trichoscopic, and genetic features of a rare case of Griscelli syndrome; moreover, we provide an overview of all the GHSs known to date. Our report highlights how an accurate clinical examination with noninvasive methods, like trichoscopy, may play a crucial rule in diagnosis of rare and potentially lethal genetic syndromes such as Griscelli syndrome, in which timely diagnosis and therapy may modify the clinical course, quality of life, and likelihood of survival.

Piebaldism in children

Piebaldism is a rare autosomal-dominant disorder of melanocyte development characterized by congenital poliosis and stable patches of leukoderma. Initially, these clinical features may be the presenting signs of various syndromes or associated diseases, which should be considered in the differential diagnosis. We present the case of a 14-year-old adolescent girl with piebaldism, along with a review of the pathogenesis, diagnosis, and management of this disease entity.

PARTIAL OCULOCUTANEOUS ALBINISM AND IMMUNODEFICIENCY SYNDROMES: TEN YEARS EXPERIENCE FROM A SINGLE CENTER IN TURKEY

BACKGROUND AND AIM

Partial oculocutaneous albinism and immunodeficiency (OCA-ID) diseases are autosomal recessive syndromes characterized by partial hypopigmentation and recurrent infections. Moreover, some OCA-ID syndromes confer susceptibility to develop a life-threatening hyperinflammatory condition called hemophagocytic lymphohistiocytosis (HLH). We investigated the genetic, clinical and immunological characteristics of 20 OCA patients.

MATERIAL AND METHODS

Herein, we present the clinical and immunological characteristics of 20 OCA patients who referred to the Department of Pediatric Immunology, Erciyes University Medical Faculty in Kayseri, Turkey between 2004 and 2014.

RESULTS

Of the 20 OCA patients, 7 fulfilled diagnostic criteria for HLH, 9 showed defective functions of CD8 T cells and natural killer cells, and 8 received a definitive molecular diagnosis. Among the patients, we also report a patient diagnosed with two different genetic defects, in TYR and JAK3 genes, causing, respectively, OCA and ID.

CONCLUSION

Our results illustrate the variability of clinical presentations and disease severity in OCA-ID patients, with consequent challenges in diagnosing and treating these patients.

Glycogen storage disease 1a with piebaldism

A 3 and half years old male child born by consanguineous marriage presented with white forelock and symmetric hypopigmented areas present since birth, similar to his mother and elder sister. Hepatomegaly was noticed at one year of age. Liver biopsy revealed enlarged pale hepatocytes distended with glycogen. Skin biopsy revealed absence of melanin pigment in white depigmented skin. G727T gene splice mutation was diagnosed in exon 5 of 17q21 chromosome.

Piebaldism in a 2-year-old girl

Piebaldism is a rare autosomal dominant skin disorder characterized by a white forelock and depigmented patches of skin, generally located on the forehead, central chest and abdomen, upper arms, and lower extremities. We report a case of a 2-year-old girl with a typical presentation and review the literature concerning this condition.

Griscelli syndrome

The dermatology staff was called to evaluate abnormal hair on a 22-month-old Hispanic girl whose parents were first cousins. Her medical history was significant for leptomeningitis with subsequent neurologic devastation, gastroesophageal reflux disease, and recurrent respiratory infections. Her hospital course was complicated by sepsis, liver dysfunction, pan-cytopenia, and disseminated intravascular coagulation. She had developed normally for the first year of life. At 13 months she became progressively lethargic and developed floppy muscle tone; a delay in mental and motor milestones was recognized. Results of a metabolic workup were negative. On examination she was noted to have generalized excessively fair skin when compared with her parents. She had silver-gray hair (Figure 1) and white eyebrows and body hair. Her maternal grandfather and granduncles had silver hair since childhood, but were without health problems. A maternal family member was said to have light skin. The presumed diagnosis before pathologic examination was Chediak-Higashi syndrome. Hematoxylin and eosin stain tests revealed prominent melanocytes in the basal layer of the epidermis. The melanocytes were large and distended with a large volume of melanin (Figure 2). The adjacent keratinocytes were completely devoid of melanin. Application of Masson-Fontana ammoniac silver stain highlighted prominent melanocytic melanin and a relative paucity of melanin in the adjacent keratinocytes (Figure 3). Microscopic examination of her hair revealed clumps of melanin of various sizes and shapes irregularly distributed throughout the hair shaft. Ultrastructural examination of the epidermis showed the melanocytes were distended by an accumulation of large stage IV mature melanosomes. Peripheral blood smear failed to show abnormal granules, even after repeated examination. Based on the clinical features and the pathologic findings, a diagnosis of Griscelli syndrome type 2 was made.

Neurological presentation of Griscelli syndrome: obstructive hydrocephalus without haematological abnormalities or organomegaly

Griscelli syndrome is a rare autosomal-recessive disorder characterised by partial albinism, immunodeficiency, organomegaly and accelerated phases. During accelerated phases, pancytopenia, haemophagocytosis, hypoproteinemeia occur which may be accompanied by neurological deterioration. Primary neurological presentation is rare and we report a case that presented with obstructive hydrocephalus and infiltrative lesions in the brain unaccompanied by other features of accelerated phase. Biopsy of these lesions demonstrated sinus histiocytosis. Electron microscopy of hair shaft and genetic studies established the diagnosis of Griscelli disease with RAB 27A mutation.

Polarized light microscopy of hair shafts aids in the differential diagnosis of Chédiak-Higashi and Griscelli-Prunieras syndromes

PURPOSE

To study and compare the appearance of hairs from patients with Chédiak-Higashi and Griscelli-Prunieras syndromes under light and polarized light microscopy.

METHOD

Hairs from 2 Chédiak-Higashi and 2 Griscelli-Prunieras patients were obtained and examined under normal and polarized light microscopy.

RESULTS

Under light microscopy, hairs from Chédiak-Higashi patients presented evenly distributed, regular melanin granules, larger than those seen in normal hairs. Under polarized light microscopy, shafts exhibited a bright and polychromatic refringence appearance. In contrast, hair from Griscelli-Prunieras patients, under light microscopy, exhibited bigger and irregular melanin granules, distributed mainly near the medulla. Under polarized light microscopy, shafts appeared monotonously white.

CONCLUSION

Light microscopic examination of hair shafts of patients with Chédiak-Higashi or Griscelli-Prunieras syndrome reveals subtle differences that are useful in identifying both disorders, but not in distinguishing between them. We provide evidence that polarized light microscopy of hair shafts, an approach that has not been previously described, aids in differentiating between these syndromes. We propose hair study by polarized light microscopy as a helpful complementary diagnostic method for differential diagnosis between CHS and GPS, especially when the more sophisticated molecular studies are not available.

Bilateral basal ganglia involvement in a patient with Griscelli syndrome

We report a 6-year-old Iranian boy with silvery-gray hair, eyelashes and the eyebrows who was admitted because of seizures and subsequent stupor. He had previous history of acute hemiparesis at 1 year of age and hepatitis-like syndrome 3 months ago. Microscopic examination of the patient's hair shaft revealed different sized clumps of melanin seen in the center of the shafts. Bone marrow aspiration revealed erythroid hyperplasia and erythrophagocytic cells. Bilateral frontal cortical and subcortical high signal lesions, dirty white matter, high signal areas in the upper pons and in both caudates and lentiform nuclei in T2 WI were the brain MRI findings of the patient. He died in the accelerated phase of Griscelli Syndrome (GS) type 2. To our knowledge we report the first case of GS from Iran.

Anatomic modifications in the enteric nervous system of piebald mice and physiological consequences to colonic motor activity

It has been assumed that in piebald lethal mice that develop megacolon, impaired colonic motor activity is restricted to the aganglionic distal colon. Peristaltic mechanical recordings, immunohistochemistry, and quantitative PCR were used to investigate whether regions of the colon, other than the aganglionic segment, may also show anatomical modifications and dysfunctional colonic motor activity. Contrary to expectations, colonic migrating motor complexes (MMCs) were absent along the whole colon of piebald lethal homozygote mice and severely impaired in heterozygote siblings. Aganglionosis was detected not only in the distal colon of piebald homozygote lethal mice (mean length: 20.4 +/- 2.1 mm) but also surprisingly in their heterozygote siblings (mean length: 12.4 +/- 1.1 mm). Unlike homozygote lethal mice, piebald heterozygotes showed no signs of megacolon. Interestingly, mRNA expression for PGP 9.5 was also dramatically reduced (by 71-99%) throughout the entire small and large bowel in both homozygote lethal and heterozygous littermates (by 67-87%). Histochemical staining confirmed a significant reduction in myenteric ganglia along the whole colon. In summary, the piebald mutation in homozygote lethal and heterozygote siblings is associated with dramatic reductions in myenteric ganglia throughout the entire colon and not limited to the distal colon as originally thought. Functionally, this results in an absence or severe impairment of colonic MMC activity in both piebald homozygote lethal and heterozygote siblings, respectively. The observation that piebald heterozygotes have an aganglionic distal colon (mean length: 12 mm) but live a normal murine life span without megacolon suggests that aganglionosis >12 mm and the complete absence of colonic MMCs may be required before any symptoms of megacolon arise.

Piebaldism

A 46-year-old man presented with a history of a congenital pigment disorder. On physical examination hypopigmented and depigmented patches were present on the mid-forehead, anterior chest, and extremities. He also had loss of pigment of the medial eyebrows and a white forelock. The patient has a family history of a similar congenital pigment disorder, the pattern of which is indicative of the autosomal dominant disorder piebaldism.

Griscelli syndrome: Rab 27a mutation

An infant with partial albinism was suspected to have Chediak-Higashi syndrome because two of his elder siblings had albinism and died in childhood following accelerated phase. Detailed investigations of blood, hair and skin of the proband revealed that he had Griscelli syndrome.

Grover disease (transient acantholytic dermatosis) and piebaldism

A 35-year-old white man with lifelong stable white lesions on the anterior trunk and extremities presented with a pruritic papular eruption limited to the white patches. Results of a histologic examination led to a diagnosis of Grover disease (transient acantholytic dermatosis). To our knowledge, this article is the first to report an association between Grover disease and piebaldism or other depigmented disorders. We review the literature and speculate on the association between these conditions.

Piebaldism associated with congenital dyserythropoietic anemia type II (HEMPAS)

Congenital dyserythropoietic anemias (CDAs) are a group of relatively rare inherited anemias. They are characterized by ineffective erythropoiesis and classified as three major groups and a number of variants. CDA type II, also known as hereditary erythroblastic multinuclearity with a positive acidified serum test (HEMPAS), is the most frequent one. A number of associations with CDA II have been reported, although each described only one or a few patients. Here we presented a piebald woman with vaginal atresia who was tested for anemia and diagnosed as CDA type II. Piebaldism and anemia association were previously described in the mouse. Our case was the first that shows the features of both piebaldism and CDA in the same patient. This association may suggest a stem cell defect to cause both hematopoietic and cutaneous manifestations.

Association of piebaldism and neurofibromatosis type 1 in a girl

We report an 11-year-old girl with both piebaldism and neurofibromatosis type 1 (NF1). The patient had large depigmented patches on her lower limbs and a white forelock since birth. In addition, some café au lait spots were present on her trunk at birth and had increased in number and size during childhood in concomitance with the appearance of axillary and inguinal freckling. Neither neurofibromas nor Lisch nodules were detected and the patient was otherwise healthy. Pedigree analysis revealed inheritance for piebaldism on the paternal side. To our knowledge, the association of piebaldism and NF1 has been described previously in only three patients. Awareness of this rare association is relevant to ensure early diagnosis and adequate follow-up for NF1.

Accelerated phase in partial albinism with immunodeficiency (Griscelli syndrome): genetics and stem cell transplantation in a 2-month-old girl

A 2-month-old girl presented with fever, hepatosplenomegaly, pancytopenia, hypertriglyceridaemia and silvery-greyish hair, suggesting the diagnosis of Griscelli syndrome (partial albinism with immunodeficiency). This diagnosis was confirmed by the characteristic agglomeration of melanin in the hair shaft and accumulation of melanosomes in melanocytes of the skin. The patient was homozygous for polymorphic markers around the myosin-Va gene on chromosome 15q21, which co-localize to the Griscelli disease locus. Natural-killer cells were in the lower range. The stimulation of lymphocytes with antigen and mitogen was normal. The patient's accelerated phase, characterized by haemophagocytosis was treated with prednisolone, rabbit anti-thymocyte globulins, and intrathecal methotrexate. Remission was maintained with cyclosporin A until HLA-compatible peripheral blood stem cell transplantation from her mother.

CONCLUSION

The silvery-greyish hair associated with fever, pancytopenia and hypertriglyceridaemia is the clue to early diagnosis of Griscelli syndrome and important to prevent death before stem cell transplantation.

Treatment of extensive hypomelanosis with autologous cultured epithelium

Successful repigmentation was achieved in 6 patients with three types of hypomelanosis (vitiligo, piebaldism, and albinism) by transplantation of fresh, autologous cultured epithelium with melanocytes. A small piece of uninvolved skin was taken for cultivation from a site adjacent to the lesion. Epidermal cells were cultured according to Green's technique. The lesions were abraded superficially and autologous cultured epithelium was applied. The grafts with functional melanocytes took completely and the wounds healed with minimal scarring. Repigmentation was visible within 6 to 8 months. The skin color resembled the surrounding normal skin except in the albinistic patient, in whom the donor skin was taken from a hyperpigmented area. Histochemical examination revealed dopa-positive melanocytes 12 to 17 days after grafting in the basal layer of the epidermis and the dermis. These cells grew in the basal layer of the epidermis and the hair follicles. Melanistic granules were visible in the keratinocytes in 1.5 months. A normal number of dopa-positive melanocytes and melanistic granules were seen in approximately 8 months. Thus, the autologous cultured epithelial grafting procedure is a promising treatment for patients with hypomelanosis.

Piebaldism, Waardenburg syndrome, and related disorders of melanocyte development

Recent years have seen the identification of a complex network of interacting genes that regulates embryonic development of melanocytes, and many different genetic disorders of melanocyte development of both humans and the laboratory mouse have now been associated with abnormalities of these regulatory genes. Disorders of melanocyte development are characterized by heterogeneous distribution of pigmentation, so-called 'white spotting,' typified by piebaldism and Waardenburg syndrome. It is now clear that these disorders of pigment cell development represent a subgroup of the neurocristopathies, involving defects of various neural crest cell lineages that include melanocytes, but also involving many other tissues derived from the neural crest.

Piebaldism--a case report

We report a familial case of piebaldism affecting a 33-year-old man and his 3-month-old son. Typical skin findings, white forelock and amelanotic white macules containing hyperpigmented macules, were characteristically presented on both patients.

Graft-versus-host reaction affecting lesional skin but not normal skin in a patient with piebaldism

A case of graft-vs.-host disease (GVHD) arising solely within an area affected by piebaldism is described. The patient, a 35-year-old woman with a single hypopigmented patch on the right leg present since birth, had received an allogeneic bone marrow transplant (BMT) from an HLA-identical sibling donor, for treatment of a myelodysplastic syndrome (MDS). Beginning on day +38 post-BMT, the patch developed changes which were histologically consistent with GVHD. Syngeneic mixed epidermal cell-lymphocyte reaction (MECLR) testing of tissue from the patch, and from adjacent normal skin, showed differences which suggest that piebaldism-affected skin is immunologically different from normal skin. These findings may offer new insight into the pathophysiology of this disorder.

Human piebaldism: relationship between phenotype and site of kit gene mutation

Human piebaldism is a rare autosomal dominant disorder characterized by congenital depigmented patches of skin and hair. Piebaldism results from mutations of the kit proto-oncogene, which encodes a cell-surface receptor, tyrosine kinase, whose ligand is the stem/mast cell growth factor. We report four unrelated patients with piebaldism and consider the variations in phenotype in relation to the site of the kit gene mutation.

Griscelli syndrome: report of three cases

The clinical features of three children with Griscelli syndrome and autopsy findings of two are presented. The patients were 5 years, 9 months, and 3 months old, respectively. Clinical features included partial albinism, hepatosplenomegaly, and various neurological symptoms. Light and electron microscopic studies of the skin were compatible with Griscelli syndrome. Postmortem examination of the viscera and central nervous system revealed lymphohistiocytic infiltration with erythrophagocytosis. Bilateral diffuse involvement of the central nervous system, cranial nerve, and spinal cord was detected in both cases.

Kit ligand/mast cell growth factor-independent differentiation of mast cells in myelodysplasia and chronic myeloid leukemic blast crisis

Autonomous, factor-independent growth and differentiation of malignant cells in preleukemic and leukemic disease states is a well-recognized phenomenon and is often associated with a poor prognosis. Mast cells are distinct hematopoietic cells and express a unique profile of antigens. Growth and differentiation of normal mast cells is dependent on mast cell growth factor (MGF), the ligand of the c-kit protooncogene product. In this study, we screened for mast cell-lineage involvement in 52 patients suffering from myeloid leukemias, myelodysplastic syndromes (MDS), systemic mastocytosis, or other diseases by probing for mast cell-related molecules (c-kit, tryptase, histamine, and MGF) and by analyzing kit ligand/MGF-independent growth of mast cells in long-term suspension culture. Of the 52 patients tested, 2 patients with refractory anemia with excess of blast cells in transformation and 1 patient suffering from chronic myeloid leukemia blast crisis (CML-BC) were diagnosed as mastocytic disease. These patients were characterized by complex chromosomal abnormalities, splenomegaly, high percentages of circulating metachromatic cells (5% to 25%), high levels of cellular tryptase (> 10 ng/10(5) peripheral blood mononuclear cells/mL) and a tryptase/histamine (ng:ng) ratio greater than 1. The metachromatic cells expressed the mast-cell-related surface antigen c-kit, but not basophil-related antigens (CD11b, CDw17). Furthermore, in these 3 patients, spontaneous, MGF-independent growth of mast cells along with spontaneous synthesis of tryptase was demonstrable in long-term culture. No autocrine production, paracrine production, or overproduction of MGF was found. The spontaneous growth of mast cells could neither be abbrogated by addition of monoclonal antibodies (MoAbs) to c-kit nor by MoAbs against MGF (< 5% inhibition), whereas factor (MGF)-dependent differentiation of mast cells in these patients could be abbrogated by MoAbs to c-kit or MoAbs to MGF (> 70% inhibition, P < .001). In addition, serum MGF levels in these patients were within the normal range and MGF could not be detected in cell-free culture supernatants. All 3 patients showed rapid progression of disease and had a survival time of less than 1 year. In conclusion, we describe a unique form of transformation in MDS and CML-BC characterized by mast cell lineage involvement and factor-independent differentiation of mast cells. This form of leukemic transformation has to be delineated from chronic myeloid leukemia with basophilia or basophil crisis, from primary mast cell leukemia, and from monocytic leukemias and myelodysplastic disorders associated with basophilia.

[The "lethal white foal" syndrome]

The lethal white foal syndrome (congenital intestinal aganglionosis) was diagnosed by history, clinical signs and pathological findings in a female foal, born in March 1992, that was an offspring of two overo-spotted paint horses. The syndrome is a congenital innervation defect of the gastrointestinal tract. A literature review of this condition, relatively unknown in Germany, is given.

Spontaneous contraction of leukodermic patches in Waardenburg syndrome

Waardenburg Syndrome is an autosomal dominantly inherited disorder with variable penetrance. It is a rare disorder with an estimated frequency of 1:20,000 in Kenya (East Africa) and 1:40,000, in the Netherlands presenting with or without deafness. The frequency with deafness is lower, estimated at 1:50,000 to 1:212,000. The major characteristic features are as follows, with reported incidences in parenthesis: 1) Dystopia canthorum (99%); 2) synophrys (17%-69%); 3) broad nasal root (78%); 4) depigmentation of hair, skin, or both (17%-58% with white forelock); 5) heterochromic or hypochromic irides (greater than 20%); 6) congenital deafness (9%-38%). Genetic heterogeneity has led to classification of affected families as type I, with dystopia canthorum, or type II, without dystopia canthorum (2, 6). Piebaldism and Woolf's Syndrome can present with pigmentary changes which are similar to Waardenburg Syndrome. Woolf's Syndrome also includes deafness. However, the distinguishing structural ophthomologic abnormalities of dystopia canthorum, broad nasal root, and synophrys are not found in either piebaldism or Woolf's Syndrome. The congenital patterns of leukoderma in both piebaldism and Waardenburg Syndrome has been believed to be stable throughout the lifetime of the affected individuals. We report an otherwise typical family with Waardenburg Syndrome, type I, in which 2 members atypically demonstrate spontaneous pigmentation and contraction of congenital leukodermic patches. To our knowledge, this has not been previously reported in Waardenburg Syndrome.

Ultrastructural study of two patients with both piebaldism and neurofibromatosis 1

Piebaldism was associated with neurofibromatosis 1 (NF-1) in two patients, an association not previously reported. Dopa staining (tyrosinase) and electron microscopy were performed: no melanocytes or melanosomes were found in hypomelanotic skin of patient 2 and in the white forelock skin of patient 1; in patient 2, normal melanocytes and melanosomes were present in the white forelock epidermis but absent from the cortex, cuticles, and inner root sheath of the white forelock hair. Because these structures receive melanosomes from melanocytes in the hair bulb, it was assumed that there were no melanocytes in the hair matrix. Melanocytes and melanosomes were normal by ultrastructural criteria and in terms of their distribution in a normally pigmented macule within a hypomelanotic patch of patient 2. These and earlier report findings led to three conclusions: subtypes of piebaldism exist, including our patients showing a combination of piebaldism and NF-1; the most commonly reported subtype has no melanocytes in the white forelock and hypomelanotic skin, although microscopic islands of melanocytes may exist within hypomelanotic skin; and the ultrastructure of white forelock skin and hair of patient 2 is consistent with a mouse model of piebaldism, in which the hair follicle has no active melanocytes, but the interfollicular epidermis is normally melanized.

[The Griscelli-Prunieras syndrome: a case report]

It is presented a six-year-old girl with silvered hair syndrome, of Griscelli-Prunieras variety; hereditary sickness with regressive autosomic and distinguished by partial albinism and leukocytic alterations. She presented the acute phase of the sickness distinguished by: hepatosplenomegaly, thrombocytopenia, lymphadenopathy generalized, and systematic infection; it is corroborated how a hemophagocytic syndrome; during her evolution developed pancerebellar syndrome. By laboratory were corroborated: decrease phagocytosis, degranulation 0%, decrease of globulins gamma, neutropenia, skin test of PPD and Candidin negatives, there were not find the giant inclusions in bone marrow leukocyte and peripheric blood that are feature of Chediak-Higashi syndrome. Another alteration that was the distribution of mote of melanin on the hair that in the Griscelli-Prunieras syndrome are six times bigger in the Chediak-Higashi syndrome.

Partial albinism with immunodeficiency: a rare syndrome with prominent posterior fossa white matter changes

PURPOSE

To describe our experience in infants with partial albinism and immunodeficiency (PAID), a rare, recently recognized, probably autosomal recessive disorder.

PATIENTS AND METHODS

Five infants suffering from this disease were examined with CT of the brain and four of these patients also underwent MR. Four of the five children also underwent follow-up CT or MR exams.

RESULTS

Three of the patients followed with serial examinations demonstrated a rapid progress of white matter changes together with a loss of brain tissue over a few months. In all four patients subjected to follow-up, the posterior fossa white matter structures were severely involved during the course of the disease.

CONCLUSIONS

This syndrome should be added to the list of demyelinating diseases, and should be kept in mind when white matter changes are prominent in the posterior fossa.

Phenotypic, embryonic, and neonatal effects of a gene for sex-linked imperfect albinism (Sal-s) in chickens

Gross phenotypic observations, histology, and tissue culture showed that the gene for sex-linked imperfect albinism that occurred at the University of Saskatchewan (Sal-s), allows a small amount of melanin pigment to be deposited in eyes and feathers. Melanin pigment accumulates in retinal pigment epithelial and cultured neural crest cells, but neural crest cells pigmenting the feathers transfer their pigment as it is produced, and this is seen as a constant amount of color in successive generations of feathers. Despite differences from early reports, it would appear that the phenotype produced by Sal-s is essentially the same as that produced by other Sal mutations. Albinos have a high incidence of lesions in the regions of the navel, the hocks, and the nares, similar to those associated with other hypomelanic mutations in the chicken. Yolk contents appear to be used more slowly by albinos late in incubation. The increased size of the yolk sacs probably contributes directly to producing the navel lesions and indirectly to variation in hatch weight. Albinos have small bursae of Fabricius, reduced hatchability, and early growth.

Piebaldism: an autonomous autosomal dominant entity

Piebaldism is a disorder in which the major clinical features are patchy hypopigmentation of the skin and a white forelock. The manifestations of piebaldism overlap with those of other genodermatoses, in particular the Waardenburg syndrome, and it is uncertain whether piebaldism is a distinct entity. We have documented a family in which seven affected members in three generations have gross piebaldism without any additional stigmata. The intrafamilial phenotypic consistency is suggestive that this autosomal dominant disorder has independent syndromic status. Linkage studies using conventional gene markers failed to identity the locus of the faulty gene.