Clinical and Genetic Characteristics of COL2A1-Associated Skeletal Dysplasias in 60 Russian Patients: Part I.

The significant variability in the clinical manifestations of COL2A1-associated skeletal dysplasias makes it necessary to conduct a clinical and genetic analysis of individual nosological variants, which will contribute to improving our understanding of the pathogenetic mechanisms and prognosis. We presented the clinical and genetic characteristics of 60 Russian pediatric patients with type II collagenopathies caused by previously described and newly identified variants in the COL2A1 gene. Diagnosis confirmation was carried out by new generation sequencing of the target panel with subsequent validation of the identified variants using automated Sanger sequencing. It has been shown that clinical forms of spondyloepiphyseal dysplasias predominate in childhood, both with more severe clinical manifestations (58%) and with unusual phenotypes of mild forms with normal growth (25%). However, Stickler syndrome, type I was less common (17%). In the COL2A1 gene, 28 novel variants were identified, and a total of 63% of the variants were found in the triple helix region resulted in glycine substitution in Gly-XY repeats, which were identified in patients with clinical manifestations of congenital spondyloepiphyseal dysplasia with varying severity, and were not found in Stickler syndrome, type I and Kniest dysplasia. In the C-propeptide region, five novel variants leading to the development of unusual phenotypes of spondyloepiphyseal dysplasia have been identified.

Clinical and Molecular Characterization and Discovery of Novel Genetic Mutations of Chinese Patients with COL2A1-related Dysplasia.

COL2A1-related disorders represent a heterogeneous group of skeletal dysplasias with a wide phenotypic spectrum. Our aim is to characterize the clinical and molecular phenotypes of Chinese patients with COL2A1-related dysplasia and to explore their phenotype-genotype relations. Clinical data were collected, physical examinations were conducted, and X-ray radiography and genetic analyses were performed in ten families involving 29 patients with COL2A1-related dysplasia. Nine mutations were identified in COL2A1, including five novel (c.816+6C>T, p.Gly246Arg, p.Gly678Glu, p.Gly1014Val and p.Ter1488Gln) and four reported previously (p.Gly204Val, p.Arg275Cys, p.Gly504Ser and p.Arg719Cys). Based on clinical features and molecular mutations, the ten families were classified into five definite COL2A1-related disorders: four families with spondyloepiphyseal dysplasia congenita (SEDC), three with osteoarthritis with mild chondrodysplasia (OSCPD), one with Czech dysplasia, one with Kniest dysplasia, and one with epiphyseal dysplasia, multiple, with myopia and deafness (EDMMD). Based on genetic testing results, prenatal diagnosis and genetic counseling were accomplished for one female proband with OSCDP. Chinese patients with OSCDP, Czech dysplasia and EDMMD caused by COL2A1 mutations were first reported, expanding the spectrum of COL2A1 mutations and the phenotype of COL2A1-related disorders and providing further evidence for the phenotype-genotype relations, which may help improve procreative management of COL2A1-related disorders.

Association between Kniest dysplasia and chondrosarcoma in a child.

Constitutive COL2A1 mutations are associated with a wide variety of clinical manifestations known as type II collagenopathies. Among them is Kniest dysplasia, which is phenotypically variable and includes both skeletal (short trunk and limbs, kyphoscoliosis, prominent joints, and osteoarthritis) and craniofacial characteristics. Kniest dysplasia mutations primarily arise in the triple-helicoidal region of the alpha 1 (II) chain in COL2A1 between exons 12 and 24. Somatic COL2A1 mutations have been identified in chondrosarcoma, a rare cartilage forming neoplasm, with a hypermutability of the gene reported in 37% of cases. However, to the best of our knowledge, there is no reported increase in predisposition to chondrosarcoma in human collagenopathies, and no reported clinical association between these congenital diseases and cartilaginous tumors. In the case study presented here, we report the first description of an association between these two rare diseases involving COL2A1, in a child presenting with Kniest dysplasia and a grade I sphenoethmoidal chondrosarcoma. We also describe a new constitutive mutation in COL2A1.

[Kniest dysplasia due to mutation of COL2A1 gene].

OBJECTIVE: To detect potential mutation of COL2A1 gene in two children suspected for Kniest dysplasia. METHODS: The 54 exons and splicing regions of the COL2A1 gene were amplified with PCR and the product was subjected to direct sequencing. RESULTS: A missense mutation (c.905C>T, p.Ala302Val) was found in the coding region of the COL2A1 gene, which has been previously reported in abroad. The patients appeared to have short trunk dwarfism, enlarged joints and midface hypoplasia. CONCLUSION: The probands are the first cases of Kniest dysplasia described in China, and so was the p.Ala302Val mutation.

Ophthalmic and molecular genetic findings in Kniest dysplasia.

PURPOSE: To study the variability of the ophthalmic phenotype in Kniest dysplasia. Kniest dysplasia is an inherited disorder associated with defects in type II collagen and characterised by short-trunked dwarfism, kyphoscoliosis, and enlarged joints with restricted mobility. Other features include marked hand arthropathy, cleft palate, hearing loss, and ocular abnormalities (myopia, abnormal vitreous, and high risk of developing retinal detachment). METHODS: Data from eight unrelated individuals with a clinical and molecular diagnosis of Kniest dysplasia are reported. Clinical assessment included an audiogram and ophthalmological examination in all but one patient who died in the immediate postnatal period. Sanger sequencing of the COL2A1 gene was performed. RESULTS: Six of the seven patients tested were high myopes with one patient being an emmetrope. Bilateral quandratic cataracts and subluxed lenses were noted in one subject. Variable but abnormal vitreous architecture was observed in all seven individuals tested. Six of the seven patients had significant hearing impairment and five of the seven patients exhibited clefting abnormalities. One patient had bilateral retinal detachments in his twenties. Six dominant disease-causing COL2A1 variants were detected. In three cases, testing of parental samples revealed that the disease-causing variant was not present in either parent. CONCLUSION: The ophthalmic features in Kniest dysplasia are very similar to those in other disorders of type II collagen such as Stickler syndrome. It is likely that different type II collagenopathies have a similar level of ocular morbidity and regular ophthalmologic examination is recommended. Kniest dysplasia is associated with heterozygous COL2A1 mutations that are frequently de novo.

Re-alignment-procedures for skeletal dysplasia in three patients with genetically diverse syndromes.

OBJECTIVE: Disruption to endochondral ossification leads to delayed and irregular bone formation and can result in a heterogeneous group of genetic disorders known as osteochondrodysplasias. These genetic disorders arise through disturbances in the complex processes of skeletal growth causing development of unsightly skeletal deformities. METHODS : Each syndrome was diagnosed on the basis of detailed clinical and radiographic assessment. Lower limb deformities were the prime presenting feature. RESULTS: Here are presented three patients with diverse genetic syndromes, namely Wolcott-Rallison syndrome (WRS), Kniest dysplasia (KD) and Desbuquois dysplasia (DS). Genetic testing was performed in the patients with WRS and DS. The diagnosis of KD was made purely on a clinical and radiographic basis. Variable orthopaedic interventions to realign these patients' lower limbs were implemented with the aim of improving their balance and gait. CONCLUSIONS: The aim of this paper is twofold. The first part is to outline the importance of diagnosing the causes of various skeletal abnormalities in patients with osteochondrodysplasias by phenotypic and genotypic characterization. The second part is to demonstrate our techniques for surgical corrections in patients with joint laxity and malalignment and show how far techniques for growth modulation, re-alignment and ligament reconstruction have advanced.

Surfactant Metabolism Dysfunction and Childhood Interstitial Lung Disease (chILD).

Surfactant deficiency and the resultant respiratory distress syndrome (RDS) seen in preterm infants is a major cause of respiratory morbidity in this population. Until recently, the contribution of surfactant to respiratory morbidity in infancy was limited to the neonatal period. It is now recognised that inborn errors of surfactant metabolism leading to surfactant dysfunction account for around 10% of childhood interstitial lung disease (chILD). These abnormalities can be detected by blood sampling for mutation analysis, thereby avoiding the need for lung biopsy in some children with chILD.

ABCA3 Deficiency: an unusual cause of respiratory distress in the newborn.

Respiratory Distress Syndrome (RDS) is due to deficiency of surfactant and commonly occurs in preterm babies. We report the first confirmed case in Northern Ireland of ABCA3 transporter deficiency which is a rare but important cause of RDS in term babies.A 38 week gestation female infant developed respiratory distress at four hours of age. Chest radiography was consistent with RDS. The baby required repeated doses of surfactant, each resulting in transient periods of decreased ventilatory requirement and improvement in blood gases, but unfortunately she did not survive.DNA sequencing demonstrated two different mutations in the ABCA3 gene, one inherited from each parent. The baby was therefore a compound heterozygote, and both mutations were thought to be functionally significant.ABCA3 transporter deficiency is a genetic disorder that is increasingly recognized as a cause of RDS in term babies in whom congenital deficiency of surfactant B and abnormalities of surfactant protein C have been excluded. It should be considered in mature babies who develop severe RDS.

Clinical biological and genetic heterogeneity of the inborn errors of pulmonary surfactant metabolism.

Pulmonary surfactant is a multimolecular complex located at the air-water interface within the alveolus to which a range of physical (surface-active properties) and immune functions has been assigned. This complex consists of a surface-active lipid layer (consisting mainly of phospholipids), and of an aqueous subphase. From discrete surfactant sub-fractions one can isolate strongly hydrophobic surfactant proteins B (SP-B) and C (SP-C) as well as collectins SP-A and SP-D, which were shown to have specific structural, metabolic, or immune properties. Inborn or acquired abnormalities of the surfactant, qualitative or quantitative in nature, account for a number of human diseases. Beside hyaline membrane disease of the preterm neonate, a cluster of hereditary or acquired lung diseases has been characterized by periodic acid-Schiff-positive material filling the alveoli. From this heterogeneous nosologic group, at least two discrete entities presently emerge. The first is the SP-B deficiency, in which an essentially proteinaceous material is stored within the alveoli, and which represents an autosomal recessive Mendelian entity linked to the SFTPB gene (MIM 1786640). The disease usually generally entails neonatal respiratory distress with rapid fatal outcome, although partial or transient deficiencies have also been observed. The second is alveolar proteinosis, characterized by the storage of a mixed protein and lipid material, which constitutes a relatively heterogeneous clinical and biological syndrome, especially with regard to age at onset (from the neonate through to adulthood) as well as the severity of associated signs. Murine models, with a targeted mutation of the gene encoding granulocyte macrophage colony-stimulating factor (GM-CSF) (Csfgm) or the beta subunit of its receptor (II3rb1) support the hypothesis of an abnormality of surfactant turnover in which the alveolar macrophage is a key player. Apart from SP-B deficiency, in which a near-consensus diagnostic chart can be designed, the ascertainment of other abnormalities of surfactant metabolism is not straightforward. The disentanglement of this disease cluster is however essential to propose specific therapeutic procedures: repeated broncho-alveolar lavages, GM-CSF replacement, bone marrow grafting or lung transplantation.

Alterations in surfactant protein gene expression associated with premature birth and exposure to hyperoxia.

Steady-state levels of mRNAs for the three surfactant-associated proteins, SP-A, SP-B, and SP-C, were measured in a primate model of premature birth and survival. These values were determined by Northern and quantitative slot blot analyses of total lung RNA during both in utero and extrauterine development of the fetus as well as in response to hyperoxic exposure. The composition and surface properties of surfactant were also analyzed to determine the effect of differential expression of the surfactant proteins on the overall composition and function of surfactant. The data clearly demonstrate that the regulation of surfactant mRNA levels in the premature fetus is under complex physiological control. Interruption of in utero development by premature birth results in increased levels of all three surfactant mRNAs, presumably in response to precocious initiation of air breathing. Within the first 24 h after parturition both SP-B and SP-C mRNA levels are increased beyond the levels found in the full-term fetal controls. Expression of mRNA for these genes peaks on day 2 and thereafter drops to levels below that found on day 1. However, response of the SP-A gene to premature birth is slow and transcripts from this gene lag considerably behind values found in the full-term fetus. Furthermore, exposure of the premature fetus to hyperoxia results in an increase in the steady-state levels of SP-B and SP-C mRNA without significant changes in SP-A. Defects in the ability of the SP-A gene to respond to extrauterine exposure and hyperoxia may be contributing to development of bronchopulmonary dysplasia, a common clinical complication of premature birth in humans.

Factors associated with neonatal problems in twin gestations.

We examined the neonatal outcome of 644 twins weighing 500 g or more and 656 singletons, born in the years 1984-1986 in the Soroka Medical Center, Beer-Sheva, Israel. There was nearly a four-fold risk of antepartum death in twins vs singletons, which disappeared when birth weight was controlled for. The risks for intrapartum and early neonatal mortality were not raised in this population. A statistically significant relative risk for congenital heart malformations in twins vs singletons remained (RR = 5.0, 95% CI = 1.5-16.3), after controlling for maternal age. Significantly higher rates of hyalin membrane disease, hypoglycemia, hyperbilirubinemia, anemia and septicemia were found in twins. Controlling for the confounding of the association between twinning and mortality or morbidity caused by differences in distributions of mode of delivery or gestational age between twins and singletons, was not as efficient as the controlling for birth weight. Thus, adjustment for birth weight removed all the excess risks detected except in hypoglycemia. Our findings suggest that the lower birth weight of twins, which is so intimately associated with multiple gestations, is probably the single most important factor associated with neonatal problems found in twin births.

Digestive tract and renal small vessel hyalinosis, idiopathic nonarteriosclerotic intracerebral calcifications, retinal ischemic syndrome, and phenotypic abnormalities. A new familial syndrome.

A new familial syndrome that affected 3 of 7 siblings is described. All 3 patients were young women with a very peculiar phenotype, poikilodermia and hair greying, and idiopathic nonarteriosclerotic cerebral calcifications. Pathological studies demonstrated a marked and progressive hyalinosis involving capillaries and often arterioles and small veins of the digestive tract, kidneys, and calcified areas of the brain. Using electron microscopy, we found that the hyalin substance in the intestinal capillaries consisted of several concentric layers of basal membrane-like deposits within a finely granular fluffy material. Huge deposits of this material were present in the subepithelial and mesangial spaces of the kidneys. Endothelial cells and, in the kidneys, mesangial cells were markedly abnormal, and a true mesangiolysis pattern was present in 2 patients. The clinical and biologic expression of these vascular changes was variable. Diarrhea, rectal bleeding, malabsorption, and protein-losing enteropathy were the main and lethal clinical problems in the proband. Hypertension appeared in the early stage of a second pregnancy in 1 sister, and mild proteinuria was found in all 3 affected patients. Peripheral retinal ischemic syndrome and chorioretinal scars were found in the ocular fundi of both affected sisters of the proband. A subarachnoid hemorrhage, due to a right sylvian aneurism, also occurred in both sisters and was lethal in 1 sister. None of the known causes of distal vessel hyalinosis could be ascertained.

Factores de riesgo en la membrana hialina / Risk factors in hyaline membrane

El presente reporte es una investigación epidemiológica de casos y controles, para determinar el riesgo relativo de algunos factores vinculados con la enfermedad de membrana hialina en el recién nacido. El riesgo de un recién nacido de bajo peso, independientemente de la edad gestacional, es 23.8 veces mayor que los niños de peso normal. El riesgo de un producto pretérmino es 14.4 veces mayor que en los productos a término de padecer membrana hialina. La edad materna y el antecendente de un hermano con membrana hialina es factor de riesgo también importante. El riesgo en los niños nacidos por la operación cesárea es 2.75 veces mayor al del niño nacido por vía vaginal

Fetal lung maturation in twin gestation.

Clear amnionic fluid was collected at cesarean section and the lecithin/sphingomyelin (L/S) ratio was used to evaluate fetal lung maturation in 42 twin gestations. The L/S ratios of twin pairs were usually similar in both numerical value and predictive accuracy except when the greater L/S ratio from one member of a pair indicated borderline lung maturity. Twin fetal lung maturation was found to be independent of sex, zygosity, and birth weight discordance. Comparison of mean L/S ratios in twins to those of uncomplicated singleton pregnancies revealed that fetal lung maturation occurred several weeks earlier in twins.

Family history of asthma in infants with bronchopulmonary dysplasia.

The role of genetic or familial factors in the development of bronchopulmonary dysplasia (BPD) has not been evaluated. Detailed histories concerning asthma, allergy, and other lung diseases were obtained on first and second degree relatives of 17 infants with BPD, and 21 infants who had hyaline membrane disease but who did not develop BPD (HMD group). All infants in the BPD and HMD groups had hyaline membrane disease requiring assisted ventilation and greater than 50% inspired oxygen in the first five days of life. The diagnosis of HMD and BPD were made on radiographic and clinical criteria. Of the 17 infants with BPD, 13 had first or second degree relatives with physician-diagnosed asthma, compared to seven of 21 in the HMD group (P less than .01). In addition, a significantly greater number of relatives of BPD infants (P less than .005) had been hospitalized for their asthma as compared to HMD relatives. There were no differences between the groups for allergic rhinitis, eczema, bronchitis, emphysema, chronic cough, smoking, or wheezing with respiratory illnesses. These results suggest the possibility that airways with a genetic predisposition for reactivity may become highly reactive following neonatal lung disorders and their treatment. These irritable airways may then contribute to the development, or progression, or both of BPD.

Hyaline membrane disease in twins. A 7 year review with a study on zygosity.

We reviewed 294 pairs of twins born from January, 1966 to December, 1972. In 19 pairs one or both members developed hyaline membrane disease (HMD). Of these, both twins were affected in 12 pairs, twin B alone in six pairs, and twin A alone in one pair. The group affected (19 pairs) had lower gestational age, birth weight, Apgar score, increased incidence of monozygotic (MZ) twins, and higher mortality rate than the group without HMD (275 pairs). MZ twins were more immature than dizygotic (DZ) twins (p less than 0.02). When both twins were affected they had lower gestational age, birth weight, and increased monozygosity than when B alone was affected (p less than 0.05). When twin B alone was affected, he had lower Apgar score than twin A (p less than 0.05). We suggested that (1) HMD occurs in twins because of lung immaturity, as it does in singletons; (2) monozygosity may be a predisposing factor to HMD because of the associated prematurity; and (3) the greater risk of twin B is probably related to birth asphyxia.