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Biomedical subjects

D L Rimoin

Publications and source records attributed to D L Rimoin.

At least 91 records · Page 5Linked to original sources
PubMed1993

Prenatal diagnosis of the skeletal dysplasias.

OBJECTIVE: We examined the accuracy of prenatal diagnosis of skeletal dysplasias and ways to refine this ability. STUDY DESIGN: A total of 226 fetuses and stillbirths referred for suspected skeletal dysplasia were evaluated. The fetal age, mode of ascertainment, and referring diagnosis were analyzed with regard to the final diagnosis. RESULTS: The leading mode of diagnosis was routine ultrasonography performed between 16 and 24 weeks' gestation. Twenty-two cases (9.7%) had previous sibs, parents, or cousins affected. The most common final diagnosis was osteogenesis imperfecta. In 15 cases (7%) the fetus did not appear to have a skeletal dysplasia or an obvious dysmorphic syndrome. CONCLUSIONS: Prenatal diagnosis of skeletal dysplasia can be made as early as 14 weeks. Most cases are sporadic. Fetal radiographs help in reaching an accurate diagnosis or at least in identifying the probable lethal disorders.

Bone Diseases, Developmental↗
PubMed1993

Genetic linkage of mild pseudoachondroplasia (PSACH) to markers in the pericentromeric region of chromosome 19.

Pseudoachondroplasia (PSACH) is a dominantly inherited form of short-limb dwarfism characterized by dysplastic changes in the spine, epiphyses, and metaphyses and early onset osteoarthropathy. Chondrocytes from affected individuals accumulate an unusual appearing material in the rough endoplasmic reticulum, which has led to the hypothesis that a structural abnormality in a cartilage-specific protein produces the phenotype. We recently identified a large family with a mild form of pseudoachondroplasia. By genetic linkage to a dinucleotide repeat polymorphic marker (D19S199), we have localized the disease gene to chromosome 19 (maximum lod score of 7.09 at a recombination fraction of 0.03). Analysis of additional markers and recombinants between the linked markers and the phenotype suggests that the disease gene resides within a 6.3-cM interval in the immediate pericentromeric region of the chromosome.

Achondroplasia↗
PubMed1993

A new variant of lethal neonatal short-limbed platyspondylic dwarfism.

This article describes an unusual skeletal dysplasia in a male fetus diagnosed by ultrasound at 18 weeks of gestation. The clinical and radiologic findings resemble thanatophoric dysplasia. Histologic examination revealed abnormalities in the resting cartilage, physeal growth plate, and bone. The resting cartilage contained peculiar large chondrocytes with huge lacunae. The growth plate revealed absence of column formation and hypertrophic vacuolated chondrocytes extending far into the metaphyseal bone trabeculae. The bone was hypercellular with absence of lamellar bone. The cortical bone was scanty and woven. The histopathologic features are, therefore, unique and differ from all other well-recognized varieties of short-limbed platyspondylic dwarfism.

Bone and Bones↗
PubMed1992

Spondylometaphyseal dysplasia, Sedaghatian type.

In 1980 Sedaghatian described an Iranian infant who died shortly after birth. At autopsy, he was found to have subacute myocarditis, cortical necrosis of kidneys, and adrenal and pulmonary hemorrhage. His skeletal abnormalities included mild rhizomelic shortness of his limbs and platyspondylyl and "laciness" of the iliac wings. In 1987 Optiz et al. described another Iranian infant with a similar perinatal course and roentgenograms. This infant was born to first cousins, suggesting an autosomal recessive single gene defect. We report our findings of another infant with a lethal course.

Bone and Bones↗
PubMed1992

An amino acid substitution (Gly853-->Glu) in the collagen alpha 1(II) chain produces hypochondrogenesis.

The spondyloepiphyseal dysplasia subclassification of bone dysplasias includes achondrogenesis, hypochondrogenesis, and spondyloepiphyseal dysplasia congenita. The phenotypic expression of these disorders ranges from mild to perinatal lethal forms. We report the detection and partial characterization of a defect in type II collagen in a perinatal lethal form of hypochondrogenesis. Electrophoresis in sodium dodecyl sulfate-polyacrylamide of CB peptides (where CB represents cyanogen bromide) from type II collagen of the diseased cartilage showed a doublet band for peptide alpha 1(II)CB10 and evidence for post-translational overmodification of the major peptides (CB8, CB10, and CB11) seen as a retarded electrophoretic mobility. Peptide CB10 was digested by endoproteinase Asp-N; and on reverse-phase high pressure liquid chromatography, fragments of abnormal mobility were noted. Sequence analysis of a unique peptide D12 revealed a single amino acid substitution (Gly-->Glu) at position 853 of the triple helical domain. This was confirmed by sequence analysis of amplified COL2A1 cDNA, which revealed a single nucleotide substitution (GGA-->GAA) in 5 of 10 clones. Electron micrographs of the diseased cartilage showed a sparse extracellular matrix and chondrocytes containing dilated rough endoplasmic reticulum, which suggested impaired assembly and secretion of the mutant protein. This case further documents the molecular basis of the spondyloepiphyseal dysplasia spectrum of chondrodysplasias as mutations in COL2A1.

Amino Acid Sequence↗
PubMed1991

Deletion of 20p 11.23----pter with normal growth hormone-releasing hormone genes.

Using a molecular analysis of the DNA from a patient with a deletion of chromosome 20 [46,XX,del(20)(p 11.23)], we have excluded the growth hormone-releasing hormone (GHRH) gene from the region 20p11.23----pter. The patient had minor facial anomalies. Rieger eye anomaly, a congenital heart defect, severe failure to thrive, and a neurosecretory problem in growth hormone (GH) secretion. Since the GHRH gene was previously mapped to chromosome 20, we used molecular genetic methods to determine whether the growth abnormalities were due to the deletion of this gene. DNAs of the patient and 2 normal control subjects were analyzed by quantitative Southern blotting using a DNA probe for the GHRH gene and 2 reference DNA probes mapping to chromosome 21. The GHRH gene was found to be present in 2 copies in the patient. This indicates that the gene for GHRH maps to the region outside the patient's deletion, in 20p11.23----qter. Furthermore, our results suggest that genes other than GHRH on 20p are important for developmental steps leading to normal neurosecretory function of GH and may also be involved in generating Rieger eye anomaly. Finally, GH deficiency and Rieger eye anomaly should be sought in other patients with deletions of 20p.

Child↗
PubMed1991

Perinatal lethal hypophosphatasia; clinical, radiologic and morphologic findings.

Clinical, radiographic and morphologic analysis of nineteen cases of perinatal (lethal) hypophosphatasia was performed. Three families each had two affected offspring. All of the patients had lethal short limb dwarfism with very soft calvaria. Other clinical findings included polyhydramnios, blue sclerae and spurs in the mid-portion of the forearms and lower legs. Considerable variability was found in the skeletal radiographs. In addition to the well known radiographic features such as generalized decrease in the size of ossified bones with some bones not ossified at all, other changes observed included: 1) marked variability in the amount of bone ossification; 2) variability between patients as to which bones were most severely affected; 3) unusually dense, round, flattened, butterfly shaped; and sagittally clefted vertebral bodies; 4) variability in femoral shape including "chromosome" like, "campomelic" like, and shortening with or without metaphyseal cupping or irregularities; 5) osteochondral projections (Bowdler spurs) of the midshaft of the fibula and ulna. Recognition of the marked clinical and radiographic variability in this autosomal recessive lethal skeletal dysplasia is important for accurate genetic counseling and prenatal diagnosis.

Bone and Bones↗
PubMed1990

Atelosteogenesis type III: a distinct skeletal dysplasia with features overlapping atelosteogenesis and oto-palato-digital syndrome type II.

We present 5 cases of a short-limb dwarfism syndrome whose manifestations overlap those of atelosteogenesis and oto-palato-digital syndrome Type II. Clinical, radiographic, genetic, and histologic data are presented which demonstrate differences between our patients and previously reported cases of these other conditions. We conclude that the disorder seen in these children represents a distinct chondrodysplasia for which we propose the name atelosteogenesis Type III.

Bone and Bones↗
PubMed1990

Possible heterogeneity in spondyloenchondrodysplasia: quadriparesis, basal ganglia calcifications, and chondrocyte inclusions.

We report on 6 patients with short stature and progressive enchondromatous-like changes of the vertebral bodies and the metaphyses of the long bones. Parental consanguinity was observed in 5 of 6 cases, supporting autosomal recessive inheritance. In spite of the similarity in radiographic changes and body proportions, genetic heterogeneity is suggested by the presence of CNS calcifications in 3 patients. Two of the latter had progressive quadriparesis. We tentatively classified these patients into 2 provisional types. An iliac crest biopsy in one of the patients with "type I" disease did not demonstrate enchondromatosis. Light and transmission electron microscopic studies demonstrated large cisterns and small inclusion bodies containing a flocculent material within the rough endoplasmic reticulum of the chondrocytes. Based on the histological and radiographic findings, we propose to classify these conditions among the spondylometaphyseal skeletal dysplasias.

Adolescent↗
PubMed1990

Rearrangement of chromosome 15 in the region q11.2----q12 in an individual with obesity syndrome and her normal mother.

Rearrangement of the proximal long arm of chromosome 15 have been found in most patients with the Prader-Willi syndrome (PWS) and in some with Angelman syndrome. We present an individual with syndromic obesity and her normal mother, who both have an abnormal chromosome 15. The proposita is a 26-year-old women with marked obesity, acanthosis, nigricans, short fingers, and severe cone degeneration of the retina. She has high plasma insulin levels, hypothyroidism, and an empty sella on CT scan. High-resolution chromosome banding demonstrated an increase in band 15q12. Further analysis showed the same abnormal 15 in her normal mother but not in her normal sister. This case and recent reports in the literature indicate that duplication of chromosome 15q in the PWS region may be associated with a syndrome of obesity, acanthosis nigricans, empty sella, and rodcore dystrophy as well as with a normal phenotype. Whether normal individuals with such a duplication carry increased risk of having offspring with an obesity syndrome is yet to be determined.

Acanthosis Nigricans↗
PubMed1990

Geleophysic dysplasia: a storage disorder affecting the skin, bone, liver, heart, and trachea.

Geleophysic dysplasia is characterized by typical facies ("happy natured"), small hands and feet, short stature, hepatomegaly, and progressive cardiac disease. We describe five patients (two of whom are siblings) with this disorder and document its variable expressivity. The facies were strikingly similar with small nose, anteverted nostrils, broad nasal bridge, and long thin upper lip with flat and long philtrum. Behavior, development, and intelligence were normal. Growth delay was noticed during infancy, and the two patients who completed normal puberty had marked short stature (140 and 150 cm), with relatively lean body habitus. The hands and feet were small, with short, plump tubular bones and broad proximal phalanges, associated with marked limitation in motion of fingers and wrists. The liver was enlarged after the age of 3 years. Two patients had mild mitral and tricuspid valve stenosis and one had severe aortic stenosis. The most severely affected child died at 3 1/2 years of age of airway obstruction as a result of progressive tracheal narrowing. Lysosomal storage vacuoles were found in skin epithelial cells from three patients whose skin was examined, and in the tracheal mucosa, liver, cartilage and macrophages of the child who died. The basic defect of this autosomal recessive lysosomal storage disease remains to be determined.

Adolescent↗
PubMed1990

Tandem duplication within a type II collagen gene (COL2A1) exon in an individual with spondyloepiphyseal dysplasia.

We have characterized a mutation in the type II collagen gene (COL2A1) that produces a form of spondyloepiphyseal dysplasia. The mutation is an internal tandem duplication of 45 base pairs within exon 48 and results in the addition of 15 amino acids to the triple-helical domain of the alpha 1 chains of type II collagen derived from the abnormal allele. Although the repeating (Gly-Xaa-Yaa)n motif that characterizes the triple-helical domain is preserved, type II collagen derived from cartilage of the affected individual contains a population with excessive posttranslational modification, consistent with a disruption in triple-helix structure. The mutation is not carried by either parent, indicating that the phenotype in the affected individual is due to a new dominant mutation. DNA sequence homology in the area of the duplication suggests that the mutation may have arisen by unequal crossover between related sequences, a proposed mechanism in the evolution and diversification of the collagen gene family.

Alleles↗
PubMed1990

Quantitative histology of cartilage vascular canals in the human rib. Findings in normal neonates and children and in achondrogenesis II-hypochondrogenesis.

Knowledge of the structure of cartilage vascular canals is important for a more thorough understanding of the development of cartilage and the growth plate in the human neonate and growing child. We have studied the costochondral junction of 6 normal neonates and 12 normal children (age 4 months-16 years) and utilised quantitative histomorphometry to define the percentage tissue area occupied by canals and the number of canals/mm2. Both percentage canal area and the number of canals/mm2 were significantly greater in newborn vs. older children (percentage area: 0.42 +/- 0.15 (mean +/- S.E.M.) vs. 0.08 +/- 0.04, P = 0.003; number/mm2: 0.2 +/- 0.09 vs. 0.04 +/- 0.02, P = 0.02). Eight newborn patients with achondrogenesis II-hypochondrogenesis were also studied. Both percentage canal area and number were significantly elevated above normal (percentage area: 5.22 +/- 1.01, P less than 0.001; number/mm2: 1.45 +/- 0.26, P less than 0.001). Results presented here demonstrate that: (i) quantitative differences in vascular canal area and numbers occur during development; (ii) 10-fold increases in vascular canal area and number are present in achondrogenesis II-hypochondrogenesis. Data from normal subjects will provide normative values against which vascular abnormalities in other skeletal dysplasias can be compared.

Aging↗
PubMed1990

Calcospherite (calcification nodule) size in the short rib polydactyly syndromes.

The short rib polydactyly syndromes (SRP) are lethal neonatal skeletal dysplasias with a narrow chest, short limbs, and other abnormalities. Type II (Majewski) short rib polydactyly can be distinguished from the Type I/III (Saldino-Noonan) type on the basis of radiographic and histologic changes. Our previous transmission electron microscopic studies suggested unusual patterns of cartilage calcification in these syndromes. We evaluate calcification in the present study using scanning electron microscopy and quantitative morphometry of calcification regions digested to expose calcospherite nodules (calcification nodules), distinctive morphologic structures which form during cartilage calcification. Mean calcospherite area of the Majewski Type II SRP (3.5 +/- 0.24 x 10(-6) mm2 (3) (mean +/- sem (n) did not differ from normal control means (3.1 +/- 0.5 x 10(-6) mm2, (3)). The mean area for Type I/III, however, was significantly larger than both the control and Type II means (8.9 +/- 1.16 x 10(-6) mm2 (7), p = .001). This difference in calcospherite size adds a further differentiating feature between these two dysplasias.

Calcinosis↗
PubMed1989

Brachyolmia: radiographic and genetic evidence of heterogeneity.

Brachyolmia refers to a form of skeletal dysplasia characterized by general platyspondyly without significant epiphyseal, metaphyseal, or diaphyseal changes in the long bones. As a result of a study of 11 patients from 7 different families and a review of the literature we propose that there are 3 and possibly 4 different types of brachyolmia: 1. Hobaek type--an autosomal recessive condition with universal platyspondyly, irregular, and reduced intervertebral spaces and marked extension of the lateral margins of the vertebrae. Rectangular and elongated vertebral bodies are seen on lateral views of the spine, which become more pronounced with age. Toledo type--radiographically similar to Hobaek type but also associated with corneal opacities and precocious ossification of costal cartilage. It is uncertain as to whether this represents variability or heterogeneity. 2. Maroteaux type--an autosomal recessive disorder that is distinguished from Hobaek type by rounding of the anterior and posterior vertebral borders with less elongation on lateral view and less lateral extension on A.P. view. This type may be associated with precocious calcification of the falx cerebri, and minor facial anomalies. 3. Dominant type--a previously underscribed form which we have observed in a mother and her son. This type has the most severe vertebral changes with flattening and irregularities of the cervical spine. These clinical, radiological, and genetic differences suggest genetic heterogeneity in this group of platyspondylic disorders.

Abnormalities, Multiple↗