Hyperphosphatasia with massive osteoectasia: a 45-year follow-up.

Hyperphosphatasia is a heterogeneous group of disorders characterized by a generalized skeletal disease and increased alkaline phosphatase. Increased bone remodeling secondary to increased osteoclastic activity appears to be the underlying feature of these disorders. These disorders include juvenile Paget's disease, expansile skeletal hyperphosphatasia, hyperostosis generalisata with striations, and Camurati-Engelmann's disease, type II. The genetic mutations for a number of these disorders have been identified. We present a patient with congenital hyperphosphatasia whose clinical and radiographic features were somewhat different from these other well-defined syndromes. The patient was followed for 45 years until his death of at age 49. The patient had massive osteoectasia with dense striations involving the entire shaft of his long bones. His spine, pelvis, short tubular bones, and calvarium were also involved. He suffered hearing loss and optic atrophy, but he kept his teeth throughout his life. He was tall with a marfanoid habitus, and he had hypogonadism and hypothyroidism. There was no evidence of mental retardation, and other laboratory studies where within normal limits. This case, as well as other manifestations of hyperphosphatasia, attests to the complexity of the bone remodeling system.

Expression of serum amyloid A genes in mouse brain: unprecedented response to inflammatory mediators.

Serum amyloid A (SAA) proteins were originally identified as prominent acute-phase serum proteins synthesized predominantly by hepatocytes. These small proteins are remarkably lipophilic, and we have sought evidence for their synthesis in mouse brain. RT-PCR showed constitutive expression of the murine SAA1 gene in the brains of normal BALB/cJ mice. After intracerebral inoculation with Sindbis virus, these mice predictably increase brain expression of tumor necrosis factor alpha (TNF-alpha), interleukin 1beta (IL-1beta), and IL-6. However, brain SAA1 expression fell after injecting either virus or control saline and remained low despite increases in TNF-alpha and IL-6, which are known to induce its expression in hepatocytes. Our data thus show that expression of the murine SAA1 gene has different, unprecedented control in mouse brain, suggesting that the protein itself may have a different physiological role there.

A fusion protein between serum amyloid A and staphylococcal nuclease--synthesis, purification, and structural studies.

We developed a recombinant DNA system to overexpress a fusion protein between the small, minimally soluble acute phase serum protein, serum amyloid A (SAA), and the bacterial enzyme staphylococcal nuclease (SN). This fusion protein is very soluble and is immunoreactive to polyclonal anti-SAA antibodies. Tryptophan fluorescence shows smooth denaturation curves for the fusion protein in guanidinium HCl or potassium thiocyanate. Fluorescence also indicates that only a single tryptophan residue (of the four present) is accessible to iodide quenching and, presumably, is exposed on the surface of the fusion protein. Circular dichroism (CD) shows a significant signal indicating alpha-helix, which can be attributed to the SAA portion of the molecule; these are the first CD spectral data available for SAA. pH titration shows persistence of helix domains for the fusion protein at pH 3.0, in contrast to the denaturation of SN under the same conditions. (The entire fusion protein shows a random coil pattern below pH 3.0.) By exploiting the structural and solubility properties of SN, this fusion protein has provided the first structural data about SAA-the precursor of the amyloid deposits in secondary amyloidosis. This fusion protein should be useful for further physical and physiologic studies of SAA.

Canine genetic linkage study using heterologous DNA probes.

We have used clones of 17 single-copy human DNA sequences to analyze their counterparts in the genome of the domestic dog by heterologous hybridization. Ten of the 17 sequences represented anchor loci proposed for comparative mammalian mapping. Eight of 17 human clones (including three of the anchor loci) gave clear hybridization signals when used with Southern blots of canine DNA. Five of these eight (including two anchor loci) showed diallelic restriction fragment length polymorphisms in a large kindred of Brittany spaniels and could be used for segregation studies. Several probes chosen from different human chromosomes also were unlinked in the dog. By contrast, linkage was found between the canine counterparts of the closely linked human serum amyloid A gene family. Three markers linked on human chromosome II appeared not to be syntenic in the dog. DNA markers linked to various human genetic neuromuscular diseases were not linked to hereditary canine spinal muscular atrophy which segregates in this kindred. However, there was evidence of possible linkage of this disorder with a canine counterpart of the tyrosinase gene. Segregation studies using heterologous single-copy DNA probes can be performed in dogs, but the level of inbreeding may reduce heterogeneity and limit the power of the analysis.

Cleft palate with autosomal recessive transmission in Brittany spaniels.

In the course of maintaining a large colony of Brittany spaniels for studying a dominantly inherited motor neuron trait, cases of sporadic complete cleft palate were observed. Without intervention, the pups with cleft palate that attempt to nurse, aspirate and die. In this study, we report on the incidence of cleft palate in this dog kindred, describe the gross morphologic characteristics of the cleft, and present a morphometric analysis of the skull of two of the cleft palate pups and one unaffected pup that died at birth. Our data thus far indicate 26.9% incidence of cleft palate in the colony. Pedigree analysis indicates that this cleft palate trait is inherited as an autosomal recessive. High resolution computed tomography scans of the pup heads were used in morphometric comparison of normal and cleft palate pups. We found specific morphologic differences between the cranial base and palate of normal and cleft palate pups. Plans for future studies of the genetics and growth and development of this animal model are discussed. This canine cleft palate trait provides an ideal model for studying a malformation common in humans.

Chromosomal rearrangement segregating with adrenoleukodystrophy: a molecular analysis.

The relationship between X chromosome-linked adrenoleukodystrophy and the red/green color pigment gene cluster on Xq28 was investigated in a large kindred. The DNA in a hemizygous male showed altered restriction fragment sizes compatible with at least a deletion extending from the 5' end of the color pigment genes. Segregation analysis using a DNA probe within the color pigment gene cluster showed significant linkage with adrenoleukodystrophy (logarithm of odds score of 3.19 at theta = 0.0). These data demonstrate linkage, rather than association, between a unique molecular rearrangement in the color pigment gene cluster and adrenoleukodystrophy. The DNA changes in this region are thus likely to be helpful for determining the location and identity of the responsible gene.

Chromosomal rearrangement segregating with adrenoleukodystrophy: associated changes in color vision.

A patient from a large kindred with adrenoleukodystrophy showed profound disturbance of color ordering, color matching, increment thresholds, and luminosity. Except for color matching, his performance was similar to blue-cone "monochromacy," an X chromosome-linked recessive retinal dystrophy in which color vision is dichromatic, mediated by the visual pigments of rods and short-wave-sensitive cones. Color matching, however, indicated that an abnormal rudimentary visual pigment was also present. This may reflect the presence of a recombinant visual pigment protein or altered regulation of residual pigment genes, due to DNA changes--deletion of the long-wave pigment gene and reorganized sequences 5' to the pigment gene cluster--that segregate with the metabolic defect in this kindred.

Visual pigment gene changes in adrenoleukodystrophy.

PURPOSE: The gene for X-linked adrenoleukodystrophy, a neurodegenerative disorder, is closely linked to the red/green color pigment genes on the distal X-chromosome Xq28 and one kindred is known to have a genetic change affecting both loci. The purpose of this article is to perform a systematic assessment of the frequency of this situation in many affected kindreds. METHODS: Recombinant DNA probes were used in blot hybridization studies to determine the structure of the color pigment genes in affected males from 59 different adrenoleukodystrophy kindreds. Whenever possible, color vision was measured using the Farnsworth 100-Hue test. RESULTS: Eleven of the 59 kindreds had abnormal color pigment gene clusters; these included fusion genes and changes in gene number. Only one kindred had a deletion of sequences immediately 5' to the color pigment genes. CONCLUSIONS: The incidence of color pigment gene changes in our 59 adrenoleukodystrophy kindreds is approximately twice the frequency of defective color vision reported in historic studies but is about the same as that found in studies of the actual genes in large populations. However, the range of changes in the color pigment genes in adrenoleukodystrophy is broader than encountered in most populations. Changes in the highly conserved color pigment genes reflect reorganizations in the Xq28 chromosomal region, some of which involve the contiguous gene for adrenoleukodystrophy.

Adrenoleukodystrophy: overlapping deletions point to a gene location in Xq28.

Adrenoleukodystrophy is a lethal X-linked neurodegenerative disorder which maps close to the red/green color pigment gene cluster in Xq28. We have reported a broad spectrum of color pigment gene changes in adrenoleukodystrophy patients, indicating that the genes may be quite close together. We now have used anonymous DNA probes centromeric to the color pigment gene cluster to analyze patients from 59 adrenoleukodystrophy kindreds. All patients showed normal hybridization using probe Fr9, 30 kb centromeric to the color pigment genes. However, using probe Fr11, 100 kb further centromeric, we found overlapping deletions in 2 patients. We isolated conventional and cosmid genomic clones encompassing 24 kb surrounding Fr11; the clones and map derived from this region localize the telomeric ends of the two deletions to distinct positions 8 kb apart. These overlapping deletions implicate this specific region as a likely site for the ALD gene.

Serum amyloid A gene transcription in synovial cells during retroviral arthritis.

In situ hybridization was used to demonstrate serum amyloid A (SAA) gene expression in arthritic joint tissue from lentivirus-infected sheep and goats. SAA gene transcription occurs in isolated individual synovial cells and occasional giant cells but not in uninfected or uninflamed synovial tissue. These findings support the notion (derived from in vitro observations) that at least one member of the SAA gene/protein family may function as an autocrine collagenase inducer in inflammatory arthritis. Since we used heterologous DNA probes derived from human clones, our findings also support the growing evidence for interspecies conservation of SAA genes.

Familial amyloidosis, Finnish type: G654----a mutation of the gelsolin gene in Finnish families and an unrelated American family.

The Finnish type of familial amyloid polyneuropathy (FAF) is an autosomal dominant form of systemic amyloidosis caused by a mutation in the gelsolin gene. The mutation leads to the expression of amyloidogenic mutant Asp187----Asn gelsolin, an actin-modulating protein. We previously developed a DNA test based on amplification by the polymerase chain reaction followed by allele-specific oligonucleotide hybridization that identifies the base substitution adenine for guanine at nucleotide 654 in the gelsolin gene causing the disease. We show here that the same mutation is present in members of six apparently unrelated Finnish families and in a member of an unrelated American family. These results, taken together with previously published findings in nine additional Finnish families and another unrelated American family, indicate that most, perhaps all, FAF patients in Finland and possibly worldwide carry the same mutation. We suggest two alternative explanations: (i) the mutation arose in a very early common ancestor or (ii) the Asn187 mutation is particularly, perhaps uniquely, amyloidogenic.

The human serum amyloid A locus SAA4 is a pseudogene.

We have isolated the human genomic DNA clone GSAA4 from a size-selected Bgl II library by hybridization to a probe derived from the human serum amyloid A gene GSAA1. Sequencing the 5' end of this clone revealed a region similar to the first exon of gene GSAA1 but with significant nucleotide differences and mutation of the 3' splice site. The restriction map of the GSAA4 clone corresponds to that for the locus "SAA4" recently reported by others. Sequence and hybridization details indicate that the locus in clone GSAA4 is a member of the human serum amyloid A gene family and contains a pseudogene. Isolating GSAA4 completes the collection of clones needed to account for all bands found in blot hybridizations of human DNA using serum amyloid A gene probes.

Exclusion of linkage between familial Mediterranean fever and the human serum amyloid A (SAA) gene cluster.

We studied the relationship between the autosomal recessive trait familial Mediterranean fever (FMF) and the serum amyloid A (SAA) genes by comparing alleles of a highly polymorphic dinucleotide repeat and a conventional restriction fragment length polymorphism (RFLP) in the SAA gene cluster in Israeli FMF kindreds. By haplotype analysis, our data indicate a minimum crossover frequency of 22% between the SAA gene marker and FMF. By conventional linkage analysis this eliminates a minimum of 10.4 cM including and surrounding the SAA gene cluster as the site of the FMF mutation although SAA proteins are prominent physiologic markers of the acute attacks.

Highly polymorphic domains of the human serum amyloid A (SAA) gene GSAA1.

The DNA of the human serum amyloid A (SAA) gene GSAA1 contains several repetitive regions within its introns. We have studied length variations at one such region in the 2nd intron by selective amplification using the polymerase chain reaction (PCR) and defined oligonucleotide primers. The lengths of the repetitive regions frequently differ between individual chromosomes and can be transmitted as Mendelian markers, making them useful for genetic linkage analysis.

Hereditary canine spinal muscular atrophy: canine motor neuron disease.

Motor neuron diseases, manifest as weakness and atrophy of skeletal muscles, occur in infancy, childhood, and adult life. Some forms of this disease are inherited. Motor neurons are selectively affected and exhibit cytoskeletal pathology, primarily enlargements of proximal axons by accumulations of transported neurofilaments. A motor neuron disease, hereditary canine spinal muscular atrophy, has been discovered in Brittany spaniels. The disease is inherited as an autosomal dominant characteristic and shows striking clinical and pathological features in common with human motor neuron disease. The availability of this excellent animal model of the human condition has allowed neurobiological investigations of the dynamics of structural and chemical pathologies of vulnerable neurons.

The human serum amyloid A (SAA)-encoding gene GSAA1: nucleotide sequence and possible autocrine-collagenase-inducer function.

We have determined the genomic sequence of the human GSAA1 gene, a member of the family of acute-phase human serum amyloid A (SAA)-encoding genes. This sequence predicts a mature protein of 104 amino acids (aa), several of which differ from residues usually conserved in the sequence of SAA proteins isolated from serum. Despite coding differences, however, the four-exon structure of GSAA1 resembles that of other SAA genes in humans and mice. The N-terminal 25 aa of the mature GSAA1 protein are virtually identical to those of an 'SAA-like' autocrine collagenase inducer produced by rabbit synovial fibroblasts; the latter also differ from the corresponding aa found in SAA in serum. We propose that GSAA1 is the human gene coding for a protein closely related to the SAA, but which is adapted to this important autocrine cytokine function.

Color vision defects in adrenomyeloneuropathy.

The relationship between abnormal color vision and adrenomyeloneuropathy (AMN) was investigated in 27 AMN patients and 31 age-matched controls by using the Farnsworth-Munsell 100 Hue test. Twelve (44%) of 27 patients showed test scores significantly above normal. The axes of bipolarity determined by the testing differed widely between the patients with abnormal scores, compatible with the notion that different alterations in visual pigment genes occur in different AMN kindreds. These observations confirm our earlier impression that the frequency of abnormal color vision is increased in these kindreds, and it supports our contentions that (1) AMN (and its companion, adrenoleukodystrophy) are very closely linked to the visual pigment loci at Xq28 and (2) this proximity might provide the opportunity to observe contiguous gene defects.