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The autosomal recessive disease Chediak-Higashi syndrome (CHS) is a progressive and generally fatal disease of humans. The under lying genetic defect in CHS is unknown and prenatal diagnostic methods have not been applied to this disease. The purpose of this study was to determine if CHS chorionic cells expressed a characteristic of CHS—enlarged lysosomes—that would permit the prenatal diagnosis of the disease. Cats with CHS, which have been shown to be homologous with human CHS, were used as the model system in this study. Chorionic tissue samples were obtained from CHS and control cat fetuses and cultures of cells were established. Acid phosphatase was utilized as a marker of lysosomes and cultures of chorionic fibroblasts from CHS and control fetuses were stained histochemically for acid phosphatase. The diameter of the largest lysosomes in 150 cells of each fetus was determined. The mean (±SD) diameter (in μm) of the largest lysosomes of normal fetuses was 0.9 ± 0.13 (range 0.5–7.0 μm), whereas the mean diameter of lysosomes in CHS chorionic cells was 3.9 ± 0.65 μm (range 0.5–25 μm). These means were significantly different (P < 0.0001). These data suggest that it should be possible to diagnose human CHS in the first trimester by chorionic villus sampling.

Peripheral blood lymphocytes from clinically normal Doberman pinscher and boxer dogs were cultured for folate-sensitive and, in preliminary studies, aphidicolin-inducible fragile site expression. Both autosomal and X chromosomal fragile sites were observed in canine cells cultured under folate/thymidine depletion and in cells cultured in medium containing aphidicolin. Results from the three dogs evaluated for both folate-sensitive and aphidicolin-inducible fragile site expression showed that the frequency of fragile site expression was significantly (P less than 0.05) greater in cells cultured in medium containing aphidicolin than in cells cultured in folate/thymidine-depleted medium. Cells from the boxer dog expressed a high percentage (66.67%) of aphidicolin-inducible fragile sites in contrast to the Doberman pinscher dog in which only 21.10% of the lymphocytes expressed aphidicolin-inducible fragile sites. The frequencies of spontaneous and folate-sensitive fragile site expression did not vary significantly by breed of dog. Age of dog was significantly and positively correlated with frequency of folate-sensitive fragile site expression in dogs of the boxer breed, but not in dogs of the Doberman pinscher breed. The dog X chromosome expressed three folate-sensitive and aphidicolin-inducible fragile sites. The G-band location of these three fragile sites showed homology with three recognized constitutive common fragile sites on the human X chromosome: Xp22, Xq21, and Xq27.2. Two specific autosomal fragile sites were identified, one on the distal end of the long arm of chromosome 1 and one on the distal end of the long arm of chromosome 8. Other autosomal fragile sites were also apparent but could not be assigned reliably to specific chromosomes.

Chediak-Higashi syndrome (CHS) is an autosomal recessive disease in humans, cats, and 8 other species. The homology of CHS in humans and cats has been demonstrated. Since human CHS is a progressive, serious, and eventually fatal disease, a method for prenatal diagnosis would be desirable. This study was designed to determine whether CHS could be diagnosed prenatally by examination of amniotic fluid cells. The amniotic fluid samples were obtained from CHS and control cat fetuses on the 45th day of gestation and cultures of cells were established. Because the underlying enzyme deficiency in CHS has not been identified, it was necessary to use a secondary manifestation of the syndrome in these studies. The secondary manifestation used was the characteristic enlargement of lysosomes associated with the disease. The lysosomes of these cells were stained by acid phosphatase histochemistry and the diameter of the largest lysosome in each cell was measured by light microscopy with a calibrated ocular micrometer. The diameters of the largest lysosomes in cells of normal fetuses ranged from 0.5 to 7.0 micron (means ranged from 0.9 to 1.8 micron), whereas the diameter of the largest lysosomes in the cells of CHS fetuses ranged from 0.5 to 30 microns (means ranged from 6.4 to 12.8 microns). The approximate t-test for independent samples with unequal variances disclosed that the largest acid phosphatase-positive lysosomes in amniotic fluid cells of CHS cat fetuses were significantly larger than the lysosomes in the cells of normal cat fetuses (P less than 0.0001). This information should, by extrapolation, provide the basis for the prenatal diagnosis of human CHS by amniocentesis.

Ovine GM-1 gangliosidosis is an inherited lysosomal storage disease. Nine lambs affected with the disease were studied to characterize clinical signs and to determine if there were any pathognomonic clinicopathologic abnormalities. Evaluation included physical, ophthalmic, and neurologic examinations, complete blood counts, serum enzyme and electrolyte analyses, urinalyses, cerebrospinal fluid analyses, blood gas analyses, roentgenograms, electromyograms, and electrocardiograms. Two affected lambs had clinicopathologic tests performed before and after the onset of clinical signs. The only consistent abnormalities recognized were nonspecific signs referable to the central nervous system; predominantly ataxia, conscious proprioceptive deficit most severe in the hind limbs, blindness, and recumbency. Lambs continued to eat and drink, though at diminished levels and with loss of body condition. It was concluded that there are no pathognomonic clinicopathologic abnormalities associated with ovine GM-1 gangliosidosis, and antemortem diagnosis requires enzyme assay of leukocytes or cultured fibroblasts, or lectin histochemistry of tissues obtained by biopsy. Lysosomal storage diseases should be considered among the differential diagnoses in young animals presenting with early neonatal death or with nonspecific neurological signs, in concert with an absence of diagnostic clinicopathologic findings.

Although the autosomal recessive disease Chediak-Higashi syndrome (CHS) has been described in humans, cats, mink, cattle, mice, killer whales, blue foxes, and silver foxes, and these conditions appear quite similar, no direct evidence of the homology of this disease in the various species has been presented. To determine if CHS in humans, cats, mink, cattle, and mice is due to a mutant gene at the homologous genetic locus in each species, or alternatively, if these are merely similar syndromes, genetic complementation analysis after interspecific somatic cell (fibroblast) hybridization was performed. "Paracrystal" formation was the criterion used for the determination of complementation. The initial studies in this report were designed to characterize paracrystal formation in control and CHS fibroblasts of these five species. Most of the control fibroblasts from each species (91-96.6%) formed paracrystals upon incubation with 25 micrograms/ml of the microtubule depolymerizing agent vinblastine sulfate. A significantly (P less than 0.05) smaller percentage of the CHS fibroblasts formed paracrystals after the same incubation (except CHS mice, with 90.2% paracrystals). It was found that 52% of the human CHS fibroblasts, 60% of cat CHS fibroblasts, 47% of mink CHS fibroblasts, and 53.8% of cow CHS fibroblasts formed paracrystals. For genetic complementation analysis, human CHS fibroblasts were fused to cat, mink, cow, or mouse CHS fibroblasts with polyethylene glycol. Control fusions were human CHS fibroblasts fused with human, cat, mink, cow, and mouse normal fibroblasts. The results of complementation analysis after the fusion of human CHS with cow CHS and human CHS with mouse CHS fibroblasts were inconclusive. A lack of complementation of human CHS with cat CHS and human CHS with mink CHS fibroblasts indicates that the disease is homologous in these species.

The chicken embryo is a useful animal model for investigating problems in developmental biology and teratology. Here we report data that further define the causes of 2 different patterns of malformation (one associated with amnion abnormalities, the other with isolated neural tube defects) and death induced by making a window in the shell and subshell membranes during the first day of incubation. The interpretation of these data suggests to us the following hypotheses. An early amnion deficit spectrum or syndrome (EADS) in chicken embryos is caused by a brief (less than 10 sec) perturbation that occurs during the windowing procedure. This perturbation results in an acute increase in mechanical tension to the developing embryo and support structures, dehydration localized to the area of the blastoderm, and/or increased friction between the blastoderm and overlying vitelline and shell membranes. Isolated neural tube defects (NTDs) are caused by a longer perturbation (greater than 3 hr) consisting of increased mechanical stress across the blastoderm. The mechanical stress is associated with the introduction of a new air space over the animal pole of the yolk during windowing. The new air space causes the shape of the yolk to change (ie, to be deformed), resulting in an increase in mechanical tension across the vitelline membrane and blastoderm. NTDs involving the head are associated with significant early embryonic mortality, whereas those involving the trunk are not. Death may also be caused by cardiovascular anomalies observed in EADS. It is concluded that disturbances in morphogenesis and death in this model are, therefore, the result of extrinsic forces (eg, mechanical stress, localized dehydration, or friction) acting on different tissue types at various critical times in development. Intensity and duration of these forces on the developing blastoderm are important variables.

Genetically determined C3 deficiency in Brittany spaniel dogs shares a number of biochemical and clinical characteristics with the human disorder. In humans, the gene for C3 deficiency is a null gene that is allelic to the structural gene for C3 and is not linked to the major histocompatibility locus. The current study used allotype analysis of canine C3 in order to demonstrate that the gene for C3 deficiency in these dogs is also a null gene allelic to the structural gene for C3. In addition, preliminary pedigree analysis suggests that the gene for canine C3 deficiency is apparently not closely linked to the major histocompatibility complex of the dog. Thus, it appears that C3 deficiency in Brittany spaniel dogs not only shares biochemical and clinical features with C3 deficiency in humans, but also shares some genetic characteristics with the human disorder.

Previous reports suggest that windowing the shells of chicken eggs during the first day of incubation frequently results in dysmorphogenesis of the central nervous system. We report here data that further delineate the neural tube defects associated with this animal model. In addition, we describe another birth defect syndrome associated with windowing: the early amnion deficit spectrum (EADS). Several components of the egg are altered structurally by windowing: the shell, outer and inner shell membranes, yolk, and air space at the blunt end of the egg. A new air space is formed over the embryo as the original one at the blunt end is obliterated. A series of studies (pH, oxygen and carbon dioxide tensions, relative humidity, temperature, and deformation of the yolk documented with magnetic resonance imaging) examining individual steps of the windowing procedure and additional techniques that stimulate windowing suggest that mechanical stress causes isolated neural tube defects and dehydration causes amnion defects. These amnion defects are associated with other embryonic abnormalities suggestive of deformations consistent with EADS.

Cats with the Chediak-Higashi (CH) syndrome have abnormal hemostasis with prolonged bleeding times and normal coagulation times. Platelet aggregation induced by serotonin, ADP, and collagen was impaired. Platelets from normal and CH cats were incubated with 14C-adenine and then gel-filtered. Gel-filtered platelets (GFP) from CH cats contained 63% of the ATP, 38% of the ADP, 100% of the Ca2+, and 75% of the Mg25 of normal platelets. Serotonin could not be detected in CH platelets. Acid hydrolase and total platelet protein of CH platelets was similar to normal platelets. Gel-filtered platelets were treated with thrombin to induce maximal secretion. Secretion of ATP, Ca2+, and Mg2+ was 1.9%, 12.4%, and 16% respectively of normal platelets. ADP secretion by CH platelets was not detectable. The ATP/ADP ratio in the 14C-labeled metabolic pool of normal platelets was similar to that of total measured nucleotide pool of CH platelets. These findings suggest that in feline CH platelets, as in platelets from CH mink and cattle, there is storage pool deficiency that is virtually complete, and the virtual absence of ADP and 5HT may in part account for the abnormal hemostasis. Aggregation of platelets from CH cats was impaired, but these platelets did aggregate to arachidonate, serotonin-induced biphasic aggregation, and the aggregation response to ADP and collagen varied according to the amount of serotonin-induced TxB2 formed. These findings support a major role for arachidonate in platelet activation.

Greig cephalopolysyndactyly syndrome is an autosomal dominant form of complex polydactyly in man. Attention is called to the evidence that, on both morphological and comparative gene mapping grounds, this defect is homologous to Xt-extra toes in the mouse. The pattern of polydactyly in both species is very similar. In addition, both conditions probably map close to the T-cell receptor gamma polypeptide at 13 A2-3 in mouse and 7p15 in humans.

Ceroid-lipofuscinosis is described in Australian Cattle dogs. Lesions included storage of ceroid-lipofuscin in most tissues with characteristic ultrastructural inclusion body patterns in neurons and other cells. Dolichol concentration of the affected dog's brain was similar to those in age-matched control dog brains. However, concentrations in brain, liver and kidneys were markedly higher than in a slightly younger dog. Biochemical data including lysosomal enzyme activities exclude other lysosomal storage diseases. The clinical and pathological features of this disorder resemble those of the juvenile Spielmeyer-Vogt type of Batten disease in humans.

Histopathologic, ultrastructural and Golgi impregnation studies disclosed lesions characteristic of a neuronal lysosomal storage disease in related sheep with onset of neurologic signs at 4-6 months. Biochemical and enzymatic evaluation disclosed storage of GM1 ganglioside, asialo-GM1, and neutral long chain oligosaccharides in brain, urinary excretion of neutral long chain oligosaccharides, and deficiencies of lysosomal beta-galactosidase and alpha-neuraminidase. Retrospective and limited prospective genetic studies suggested autosomal recessive inheritance. A gene-dosage effect on beta-galactosidase levels was documented in fibroblasts from putative heterozygous sheep. Fibroblasts from affected sheep did not have increased beta-galactosidase activity after incubation with the protease inhibitor, leupeptin. In some aspects this disease is similar to GM1 gangliosidosis, but is unique in that a genetic defect in lysosomal beta-galactosidase may cause the deficiency of lysosomal alpha-neuraminidase.

Craniomandibular osteopathy is a disease of several breeds of dogs, principally West Highland White and Scottish terriers. It is characterized by a non-neoplastic proliferation of bone on the ramus of the mandible and/or the tympanic bulla. The disease in various respects resembles Paget's disease and infantile cortical hyperostosis of humans. A retrospective pedigree analysis of a kindred of West Highland White terriers was performed to determine if the trait was inherited and to determine mode of inheritance. This study indicated that in West Highland White terriers, the condition is an autosomal recessive trait.

A group of related borzoi dogs were studied over a 6-year period to ascertain the cause of primary hypothyroidism. Four generations of dogs were analyzed. Two littermates with lymphocytic thyroiditis were mated and the 10 offspring were all diagnosed, on the basis of thyroid biopsy evaluation, as having lymphocytic thyroiditis by age 2.5 years. A wide range of thyroid gland lesions was demonstrated in this litter of dogs. This report documents the occurrence of lymphocytic thyroiditis in three successive generations of an inbred group of borzoi dogs. An autosomal recessive mode of inheritance for the trait in this group of dogs is proposed.