Cervical spine in the Apert syndrome

Radiographs of the cervical spine—in many cases longitudinal—were available for study in 68 cases of Apert syndrome. Autopsy material was available in one of these cases, and a 3-dimensional reconstruction from a CT scan was also studied in one case. Variable degrees of fusion were observed, involving the articular facets, the neural arch or transverse processes, or block fusion of the vertebral bodies. Ossification may not always be evident in some early radiographs. However, early radiographic signs of impending fusion may be irregularity in vertical orientation of the vertebral bodies and narrowing of the involved intervertebral spaces. Cervical fusions occurred in 68%, single fusions being found in 37%, and multiple fusions in 31%. C₅?C₆ fusion was most common, alone or in combination with other fusions. In contrast, cervical fusions are known to occur in 25% of Crouzon patients, most commonly involving C₂?C₃ only. It appears that when fusions are present, C₅?C₆ involvement in the Apert syndrome and C₂?C₃ involvement in the Crouzon syndrome separate the 2 conditions in most cases. Because cervical anomalies may complicate an already compromised airway in any form of acrocephalosyndactyly, it is imperative to initiate radiographic study of the cervical spine before undertaking anesthesia for surgery. © 1992 Wiley-Liss, Inc.     

Growth pattern in the Apert syndrome

In this paper, we demonstrate that a discernible and unique growth pattern characterizes the Apert syndrome. The keys to understanding Apert newborn measurement values are brain size and cranial configuration. Both true megalencephaly and coronal synostosis are present at birth. Thus, the head is unusually heavy and the cranium is disproportionately high. Mean newborn length and weight are above the normal 50th centile. Of our newborn patients, 16% exceeded 4,000 g in weight. Preterm infants were appropriate or slightly large for gestational age. A biphasic linear growth pattern was found. In childhood, deceleration of linear growth occurs so that most values fall between the 5th and 50th centiles. From adolescence to adulthood, deceleration becomes more pronounced. This 2-step linear growth deceleration results in large measure from rhizomelic shortness of the lower limbs. Puberty takes place within the normal time frame. Although a disproportionate amount of the megalencephaly accounts for the dramatic increase in head height, the widely patent midline calvarial de fect, allowing the brain to expand anteriorly into the metopic area, and some increase in the head breadth permit the mean head circumference at birth to normalize slightly above the 50th centile. During the growth period, the head circumference was studied in surgically unoperated Apert patients from the 1960s and earlier. The natural history of the growing cranium consists of gradual deceleration in head circumference from slightly above the 50th centile at birth to within or at ?2 SD later on. © 1993 Wiley-Liss, Inc.     

Visceral anomalies in the Apert syndrome

We report on visceral anomalies found in 136 patients with Apert syndrome. Autopsies were only performed on 12 of these cases. Thus, the percentage of anomalies found in our patients should be considered a minimum estimate because of the possibility of clinically silent visceral anomalies, minor internal anomalies, and anatomic variations. Cardiovascular and genitourinary anomalies were found most commonly, occurring in 10% and 9.6%, respectively. As expected, complex and multiple cardiac anomalies were frequently associated with early death. Among genitourinary anomalies, hydronephrosis (3%) and cryptorchidism (4.5%, n =; 66 males) occurred most commonly. In contrast, anomalies of the respiratory system (1.5%) and gastrointestinal anomalies (1.5%) occurred with lower frequency. The finding of a solid cartilaginous trachea is particularly important because no case was diagnosed during life but rather, only at autopsy. Because cardiovascular and genitourinary anomalies occur with significant frequency, they should be considered in the workup of all Apert newborn infants. We also recommend MRI study of the trachea in any infant with signs and symptoms of lower respiratory compromise. © 1993 Wiley-Liss, Inc.     

Hands and feet in the Apert syndrome

We studied 44 pairs of hands and 37 pairs of feet in Apert syndrome, utilizing clinical, dermatoglyphic, and radiographic methods. We also studied histologic sections of the hand from a 31-week stillborn fetus. Topic headings discussed include: clinical classification of syndactyly; correlations between types of hands and feet in the same patient; dermatoglyphics; anatomy of the hand; radiologic assessment; comparison with other studies; histologic assessment of the hand; acrocephalosyndactyly vs. acrocephalopoly-syndactyly: a pseudodistinction; and some generalizations. © 1995 Wiley-Liss, Inc.     

Syndrome of short stature,microcephaly, mental retardation,and multiple epiphyseal dysplasia—Lowry-Wood syndrome

We describe a brother and a sister with a syndrome of short stature, microcephaly, mental retardation, and multiple epiphyseal dysplasia. The parents were normal. This appears to be the second example of the syndrome first described by Lowry and Wood [1975] in two boys who had epiphyseal dysplasia, short stature, microcephaly, and nystagmus; one of these patients was mildly mentally retarded. The Lowry-Wood syndrome probably is an autosomal recessive trait.     

Skeletal histopathology in fetuses with chondroectodermal dysplasia (Ellis-van creveld syndrome)

Chondroectodermal dysplasia (CED) is an uncommon autosomal recessive disorder and one of the short rib polydactyly syndromes (SRPS). It is characterized by acromelic and mesomelic shortness of limbs, postaxial polydactyly, small chest, ectodermal dysplasia, and in many cases, congenital heart defects. Controversy exists over possible changes in the growth plate. With the advent of ultrasonographic examination, increasing numbers of fetuses with osteochondrodysplasias are examined by pathologists. Since histopathologic examination of the skeletal system is useful in defining various osteochondrodysplasias and it has not been described in the fetus with CED, we herein describe 3 cases of fetal CED with emphasis on skeletal histopathology. All 3 pregnancies were terminated at 22–23 weeks because of ultrasonographic demonstration of short limbs and growth retardation. Radiologically, each fetus had acromelic and mesomelic shortness of long bones with smooth round metaphyses, vertically short iliac bones, short ribs and normal vertebrae. These findings are similar to those described in the larger newborn infant with CED. Histopathologically, the cartilage of the long bones showed chondrocytic disorganization in the physeal growth zone. The findings are dissimilar to those of larger infants and older children in whom chondrocytic columnization has been seen in the central physis and disorganization in peripheral physis. Furthermore, a variable degree of chondrocytic disorganization was also seen in the central physeal growth zone of vertebrae in these fetuses. Other findings noted at fetopsy were: polydactyly in all 3 cases, congenital heart defect in 2 and an abnormal frenulum in one case. The foregoing phenotypic and radiographic manifestations and skeletal histopathology help separate CED from other SRPS. © 1993 Wiley-Liss, Inc.     

Stickler-like syndrome due to a dominant negative mutation in the COL2A1 gene

The type II collagenopathies include a wide spectrum of phenotypes ranging from mild spondylo epiphyseal dysplasia (SED) to severe achondrogenesis/ hypochondrogenesis. Several attempts have been made at providing phenotype-genotype correlations in this group of disorders. In this report we discuss a South African family in which four members have a phenotype resembling Stickler syndrome type 1. Ocular problems and conductive deafness predominate, while skeletal changes resemble those of a mild form of multiple epiphyseal dysplasia (MED). In distinction to the classical form of Stickler syndrome, the affected persons have stubby digits. DNA analysis of the exons of the COL2A1 gene documented a C-T transversion in exon 39, resulting in an Arg704Cys substitution in the triple helical domain of the type II collagen peptide; this nontermination mutation may be indicative of further heterogeneity in the Stickler group of disorders or of a new syndrome amongst the type II collagenopathies. Am. J. Med. Genet. 80:6–11, 1998. © 1998 Wiley-Liss, Inc.     

Skeletal abnormalities in Rett syndrome: Increasing evidence for dysmorphogenetic defects

The presence of metatarsal and metacarpal abnormalities in some individuals has raised the possibility that Rett syndrome is, in fact, a multiple congenital abnormalities/mental retardation (MCA/MR) syndrome. We have conducted radiological examination of 17 cases of Rett syndrome in Western Australia. Short fourth and/or fifth metatarsals were identified in 65% of cases and short fourth and/or fifth metacarpals in 57%. Metatarsal (P = 0.045) and metacarpal (P = 0.006) shortness were significantly more common in girls 14 years or older. Negative ulnar variance (found in 79% of cases) appeared to be independent of age. Reduced bone density in the hands was found in 86% of cases. A nationwide study using the Australian Rett Syndrome Database is planned to follow up these findings and compare them with findings from a control group. The confirmation of these abnormalities in a high proportion of cases may provide morphologic markers to assist in the diagnosis of Rett syndrome and perhaps provide a further avenue of research into the pathogenesis of this disorder. © 1995 Wiley-Liss, Inc.     

Revisit of multiple epiphyseal dysplasia: ethnic difference in genotypes and comparison of radiographic features linked to the COMP and MATN3 genes

Multiple epiphyseal dysplasia (MED) is a genetically heterogeneous group of diseases characterized by variable degrees of epiphyseal abnormality primarily involving the hip and knee joints. The purpose of this study was to investigate the frequency of mutations in individuals with a clinical and radiographic diagnosis of MED and to test the hypothesis that characteristic radiological findings may be helpful in predicting the gene responsible. The radiographs of 74 Korean patients were evaluated by a panel of skeletal dysplasia experts. Six genes known to be associated with MED (COMP, MATN3, COL9A1, COL9A2, COL9A3, and DTDST) were screened by sequencing. Mutations were found in 55 of the 63 patients (87%). MATN3 mutations were found in 30 patients (55%), followed by COMP mutations in 23 (41%), and COL9A2 and DTDST mutations in one patient (2%) each. Comparisons of radiographic findings in patients with COMP and MATN3 mutations showed that albeit marked abnormalities in hip and knee joints were observed in both groups, the degree of involvement and the morphology of dysplastic epiphyses differed markedly. The contour of the pelvic acetabulum, the presence of metaphyseal vertical striations, and/or the brachydactyly of the hand were also found to be highly correlated with the genotypes. The study confirms that MATN3 and COMP are the genes most frequently responsible for MED and that subtle radiographic signs may give precious indications on which gene(s) should be prioritized for mutational screening in a given individual.     

Perceptions of the outcome of orthopedic surgery in patients with chondrodysplasias

As part of a larger survey of patients with chondrodysplasias, 197 patients or their parents were asked whether they had undergone orthopedic surgery related to their chondrodysplasia and, if so, to rate their impression of the outcome. Seventy-four patients (37.6%) had undergone a total of 152 procedures (221 if concurrent bilateral operations are counted separately). The percentage of patients treated surgically ranged from a low of 8.3% for hypochondroplasia to a high of 87.5% for diastrophic dysplasia. Of the patients who had surgery, the mean number of procedures per patient ranged from 1.0 for hypochondroplasia to 2.69 for pseudoachondroplasia. Of 180 individual procedures related to the limbs, the outcome in 88.8% was judged 'a bit better' or higher and in 68.8% 'much better' or higher. The responses ranged from a low of 70.4 and 66.7%, respectively for proximal femoral osteotomies to a high of 100 and 85.9% for hip replacement. The comparable figures for spine related surgery were 81.8 and 48.5% with a low of 58.3 and 50.0% for foramen magnum-cervical surgery and a high of 93.8 and 43.8% for thoracolumbar procedures. The expressed perception of lack of satisfaction varied not only by procedure but by diagnosis. Overall, patients perceived a high level of post-surgical improvement, although a number experienced subsequent deterioration and the need for further intervention.     

Supracondylar process of the humerus: study on 375 Caucasian subjects in Cologne, Germany

This study documents the prevalence of the supracondylar process of the humerus in the Caucasian subjects in a German dissecting room along with its morphology, height, and site by using an electronic digimatic caliper. Seven hundred and fifty dried humeri from 375 Causcasian cadavers were examined at the Department of Anatomy in the University of Cologne, Germany. The supracondylar process was found in 10 out of the 750 (1.3%) dried humeri from 10 individuals (2.7%). In five of these 10 bones, the supracondylar process was in the form of a tubercle. In the others it was a spine of average height 9.5 mm (range, 7.7-12.3 mm). The average distance of the supracondylar process from the medial epicondyle was 59.8 mm, ranging between 40.5 and 79.0 mm. The supracondylar process was more common on the left humerus (90%) and in male subjects (60%) (both P < 0.01). None of the processes we observed was bilateral. Literature review indicated that the supracondylar process appears in 0.4-2% of Caucasians and in 0.2-2.8% of their humeri.     

Short rib-polydactyly syndrome in twins: Beemer-Langer type with poly dactyly

We present premature female twin fetuses with concordant extremely shortened ribs, short limbs, macrocephaly, median cleft upper lip and facial dysmorphism. Based on radiological criteria and the pattern of associated abnormalities, a lethal short rib-polydactyly syndrome (Beemer-Langer type) was diagnosed. The differential diagnosis of this entity is discussed.     

Novel mutations in exon 2 of MATN3 affect residues within the α–helices of the A‐domain and can result in the intracellular retention of mutant matrilin‐3

Multiple epiphyseal dysplasia (MED) is a clinically variable and genetically heterogeneous chondrodysplasia characterized by mild to moderate short stature and early onset osteoarthritis. Some forms of MED result from mutations in the gene encoding the cartilage structural protein matrilin‐3 (MATN3). The majority of MATN3 mutations affect conserved residues within the β‐sheet of the single A‐domain of matrilin‐3. These mutations cause the protein to misfold and prevent its secretion from the rER, both in vitro and in vivo. More recently a single mutation (p.Phe105Ser) has been identified within the α1‐helix of the A‐domain, but its affect on the structure and/or function of matrilin‐3 is unknown. In this paper we describe the characterization of two additional α‐helical mutations (p.Ala173Asp and p.Lys231Asn) and show that both p.Phe105Ser and pAla173Asp prevent the secretion of A‐domain in vitro. In contrast, p.Lys231Asn does not prevent the secretion of matrilin‐3 A‐domain, nor does it disrupt the structure of this domain or inhibit its binding to type II or type IX collagen. Therefore, despite extensive biochemical analysis the disease mechanism of p.Lys231Asn remains unresolved and care should be taken in counseling for these types of mutation in MATN3. © 2007 Wiley‐Liss, Inc.     

Clinical and molecular characterization of Diastrophic Dysplasia in the Portuguese population

SLC26A2-related dysplasias encompass a spectrum of diseases: from lethal achondrogenesis type 1B (ACG1B; MIM #600972) and atelosteogenesis type 2 (AO2; MIM #256050) to classical diastrophic dysplasia (cDTD; MIM #222600) and recessive multiple epiphyseal dysplasia (rMED; MIM #226900). This study aimed at characterizing clinically, radiologically and molecularly 14 patients affected by non-lethal SLC26A2-related dysplasias and at evaluating genotype-phenotype correlation. Phenotypically, eight patients were classified as cDTD, four patients as rMED and two patients had an intermediate phenotype (mild DTD - mDTD, previously 'DTD variant'). The Arg279Trp mutation was present in all patients, either in homozygosity (resulting in rMED) or in compound heterozygosity with the known severe alleles Arg178Ter or Asn425Asp (resulting in DTD) or with the mutation c.727-1G>C (causing mDTD). The 'Finnish mutation', c.-26+2T>C, and the p.Cys653Ser, both frequent mutations in non-Portuguese populations, were not identified in any of the patients of our cohort and are probably very rare in the Portuguese population. A targeted mutation analysis for p.Arg279Trp and p.Arg178Ter in the Portuguese population allows the identification of approximately 90% of the pathogenic alleles.     

Molecular defects in the chondrodysplasias

There has been a recent explosion of knowledge concerning the biochemical and molecular defects in the skeletal dysplasias. Through both the candidate gene approach and positional cloning, specific gene defects that produce the skeletal dysplasias have been identified and may be classified into several general categories: 1) qualitative or quantitative abnormalities in the structural proteins of cartilage; 2) inborn errors of cartilage metabolism; 3) defects in local regulators of cartilage growth; and 4) systemic defects influencing cartilage development. © 1996 Wiley-Liss, Inc.     

Novel and recurrent mutations clustered in the von Willebrand factor A domain of MATN3 in multiple epiphyseal dysplasia

Multiple epiphyseal dysplasia (MED) is a common skeletal dysplasia characterized by joint pain and stiffness, delayed and irregular ossification of epiphyses, and early-onset osteoarthritis. Six genes responsible for MED have been identified, including COMP, COL9A1, COL9A2, COL9A3, DSTDT and MATN3. MATN3 encodes matrilin-3, a cartilage-specific extracellular matrix protein. To date, seven different MATN3 mutations have been identified; all are located within the beta-sheet regions of the von Willebrand factor type A (vWFA) domain, which is encoded by exon 2. We examined MATN3 mutations in27 Japanese MED patients who were possibly autosomal dominant inheritance and had been excluded for COMP mutations. Ten of them had a positive family history. We examined all eight exons of MATN3 by PCR and direct sequencing from genomic DNA. We have identified four missense mutations in eight unrelated families; two are novel, and two have been characterized previously. Like previously characterized MATN3 mutations, those identified in this study are clustered within exon 2, specifically in and around the 2nd beta-sheet region of the vWFA domain (aa. 120-127). Contrary to the previous assumption that the MATN3 mutation in MED is confined to the beta-sheet regions, one novel mutation (p.F105S) is located outside the beta-sheet region, within an alpha-helix region.