Cardiac reoperation in a patient with osteogenesis imperfecta: a case report.

A case of a 40-year-old man with dehiscence of the prosthetic aortic valve and recurrence of mycotic aneurysm of the left ventricular outflow tract with osteogenesis imperfecta is presented. He had an operation of aortic valve replacement and direct closure of the mycotic aneurysm for infective endocarditis twenty-one months ago. We performed reoperation of prosthetic aortic valve, patch closure of the mycotic aneurysm and graft replacement of the ascending aorta. He was complicated with multiple fractures of bilateral scapla and dislocation of left shoulder one postoperative day. Fortunately, cardiac reoperation was performed successfully in this patient despite anticipated difficulties with tissue friability with osteogenesis imperfecta.

New case of Cole-Carpenter syndrome.

We describe a girl with a severe progressive type of osteogenesis imperfecta, in association with multisutural craniosynostosis, growth failure, and craniofacial findings including ocular proptosis, marked frontal bossing, midface hypoplasia, and micrognathia. Collagen analysis was normal. These features are consistent with the diagnosis of Cole-Carpenter syndrome. This report provides further evidence for the existence of this rare genetic entity.

Perinatal lethal osteogenesis imperfecta.

Perinatal lethal osteogenesis imperfecta is the result of heterozygous mutations of the COL1A1 and COL1A2 genes that encode the alpha 1(I) and alpha 2(I) chains of type I collagen, respectively. Point mutations resulting in the substitution of Gly residues in Gly-X-Y amino acid triplets of the triple helical domain of the alpha 1(I) or alpha 2(I) chains are the most frequent mutations. They interrupt the repetitive Gly-X-Y structure that is mandatory for the formation of a stable triple helix. Most babies have their own private de novo mutation. However, the recurrence rate is about 7% owing to germline mosaicism in one parent. The mutations act in a dominant negative manner as the mutant pro alpha chains are incorporated into type I procollagen molecules that also contain normal pro alpha chains. The abnormal molecules are poorly secreted, more susceptible to degradation, and impair the formation of the extracellular matrix. The collagen fibres are abnormally organised and mineralisation is impaired. The severity of the clinical phenotype appears to be related to the type of mutation, its location in the alpha chain, the surrounding amino acid sequences, and the level of expression of the mutant allele.

[Osteoporosis in congenital disorders].

Osteogenesis imperfecta (OI) is the most prevalent osteoporosis syndrome in childhood and is characterized by fractures and skeletal deformities. In almost all individuals, OI results from mutations in one of the two genes (COL1A1 and COL1A2) that encode the chains of type I collagen. OI can be divided into four major groups, type I, II, III, and IV, that differ in clinical presentation, mode of inheritance, radiographic picture, and, for the most part, the biochemical basis of the connective disorder. The molecular basis of OI is mainly discussed.

[Lethal osteogenesis imperfecta in a Congolese newborn infant]. / Ostéogenèse imparfaite létale chez un nouveau-né Congolais.

BACKGROUND: Several forms of osteogenesis imperfecta have been described. The perinatally lethal forms (type II of Sillence) have been subclassified into groups A, B and C on the basis of radiological features. This report describes a case of type IIA. CASE REPORT: A female Congolese baby was born at term to healthy, non-consanguineous parents. No ultrasonographic studies were done during the pregnancy. The newborn suffered from acute respiratory distress at birth. Clinical examination showed bone abnormalities: shortened and bowed limbs with crepitation at mobilization, soft calvaria and narrow rib cage. X-rays showed short, broad, bowed long bones with signs of fractures; the ribs were thin and beaded; wormian bones were seen in the skull. The newborn died from respiratory distress at the age of 5 hours. All clinical and X-rays investigations of the parents, the elder brother and cousins were normal. CONCLUSION: This baby seems to have suffered from a lethal form of osteogenesis imperfecta, probably type IIA of Sillence.

Osteoporosis-pseudoglioma syndrome.

Two patients with osteoporosis pseudoglioma syndrome are described. Both are single children, born to nonconsanguineous, healthy parents. The first patient, a 17-year-old girl, had serious visual impairment since birth. She is severely dwarfed and has major skeletal deformities resulting in inability to walk since age 2 years. The second patient is an 18-year-old girl with unilateral neonatal blindness, short stature and deformities, mainly of pelvis and lower limbs. She has been able to walk with support up to now. The clinical and radiological findings in these 2 patients reflect the clinical variability of the condition. Results of collagen studies in both patients are normal and differentiate this condition clearly from severe osteogenesis imperfecta, which it resembles.

Analysis of cultured chorionic villi in a case of osteogenesis imperfecta type II: implications for prenatal diagnosis.

We examined collagens produced by cultured cells from skin, chorionic villi, and placental membranes of a 32 week fetus with osteogenesis imperfecta (OI) type II. We observed that skin fibroblasts synthesized two populations of pro alpha 1(I) chains of type I procollagen; one population was normal, while the other population had excessive post-translational modification. The thermal stability of helices containing the overmodified chains was reduced 1-2 degrees C. Most significantly, the cells cultured from chorionic villi produced type I collagen chains with the same electrophoretic abnormalities as the skin collagen. This suggests that chorionic villus sampling (CVS) is a means of prenatal diagnosis for families with a previous type II or type IV OI infant.

Radiological "metamorphosis" in a patient with severe congenital osteogenesis imperfecta.

Congenital osteogenesis imperfecta (OI) was diagnosed by ultrasound in a 31-week-old fetus, and the diagnosis confirmed after delivery by caesarean section at week 36. The baby survived the neonatal period, but failed to thrive, had recurrent respiratory infections and ultimately died at 8 months. Cultured fibroblasts synthesized both normal type I collagen and unstable type I collagen harbouring a structural defect in the alpha 1 (I) cyanogen bromide-derived peptide number 8 (CB8) region of the molecule, indicating a heterozygous dominant mutation. At birth, the radiological picture was that of the "thin bone"-type of congenital OI (OI type IIB/III in the Sillence classification); at the age of 12 weeks ribs and long bones had undergone a marked expansion giving a very different picture, that of the "thick bone"-type congenital OI (OI type IIA). The mechanism responsible for this change in bone structure is not known, but fractures and callus formation are unlikely to be the only factors. Caution is needed in the interpretation of radiographs of newborns with OI for prognostic or genetic purposes.

Osteogenesis imperfecta in childhood: cardiac and renal manifestations.

We examined 58 children aged 1-16 years with various forms of osteogenesis imperfecta (OI). Congenital cardiac malformations were diagnosed in 4 children (valvular aortic stenosis, 2 with atrial septal defect II, Fallot Tetralogy). Two additional children developed holosystolic mitral valve prolapse and regurgitation. Children suffering from a severe clinical course (type III according to the Sillence classification) showed aortic root dilatation (28%) and increased septal (40%) and posterior left ventricular wall thickening (68%) on initial evaluation. All three parameters were significantly correlated to body surface area. Kidney stones and renal papillary calcifications were detected in 4 children. Cardiovascular abnormalities and nephrolithiasis may be important extraskeletal manifestations of childhood OI.

Intrauterine diagnosis of short-limbed dwarfism.

Ten short-limbed fetuses caused by skeletal dysplasia were diagnosed prenatally from September 1984 through July 1988. The final diagnosis was thanatophoric dwarfism in 7 cases and osteogenesis imperfecta congenita in 3 cases. The diagnosis was based on sonographic findings in all cases and postnatal radiography was performed in 3 cases for further confirmation. Sonographic examinations revealed markedly shortened limbs and other associated abnormalities, including abnormal skull appearance, pear-shaped chest with protuberant abdomen, polyhydramnios and hydrops in fetuses with thanatophoric dwarfism. Fetuses with osteogenesis imperfecta congenita were characterized by fractures of the long bones. These findings were helpful in making the specific diagnosis of short-limbed dwarfism. According to our experience, sonographic examination is effective in the prenatal diagnosis of short-limbed dwarfism.

Prenatal diagnosis and prevention of inherited abnormalities of collagen.

There is now strong evidence for the implication of collagen alpha 1(I), alpha 2(I) and alpha 1(III) mutations in many forms of osteogenesis imperfecta and inherited arterial aneurysms (Ehlers Danlos syndrome type IV). A sizeable proportion of these disorders have detectable abnormalities by conventional protein chemistry, immunofluorescence, or more sophisticated DNA analysis. Everyone of them with specific defects or with linkage to appropriate gene markers is therefore amenable to prevention using conventional prenatal diagnosis by chorionic villus biopsy (with fibroblast culture), fetoscopic biopsy (with fibroblast culture), ultrasound diagnosis of the severely deformed fetus, or gene linkage studies by chorionic villus biopsy or amniocentesis. Already many collagen alpha 1(I), alpha 2(I) and alpha 1(III) mutations have been characterized including point mutations, small and large deletions and regulatory mutations. Many others are likely to be rapidly studied by exploiting recent advances in DNA technology, and other strong candidate genes include collagen II (some chondrodystrophies), collagen VI (certain arterial and cardiovascular diseases) and collagen VII (dystrophic epidermolysis bullosa). Other important common diseases are likely to include osteoporosis, osteoarthritis and cerebral aneurysms. A detailed review is provided of collagen interstitial genes and proteins, together with a description of the various forms of osteogenesis imperfecta and Ehlers Danlos syndrome in which either collagen alpha 1(I), alpha 2(I) or alpha 1(III) mutations have been identified. Appropriate restriction length polymorphisms (RFLPs) useful in identifying carriers of these mutant genes are also described.

Hydrocephalus of intrauterine onset in perinatally lethal osteogenesis imperfecta: clinical, sonographic, and pathologic correlations.

Five neonates with perinatally lethal osteogenesis imperfecta (OI) have come to necropsy at Women & Infants' Hospital of Rhode Island in the past eight years. Four had true hydrocephalus, defined as enlargement of the lateral ventricles with thinning of the cortical mantle. In all 4 hydrocephalus was diagnosed by sonography before birth. All 4 died almost immediately after birth, whereas the neonate without hydrocephalus lived for 22 days. Significant necropsy findings in the 4 with hydrocephalus included healing occipital-bone fractures with stenosis of the foramen magnum, remote and recent cerebral parenchymal and intraventricular hemorrhage, and remote and recent subarachnoid hemorrhage. True hydrocephalus of intrauterine onset has rarely been described in perinatally lethal OI, but its high incidence (80%) in this population suggests that it may be a common phenomenon. Hydrocephalus of intrauterine onset in perinatally lethal OI may indicate relatively more severe disease.

Osteogenesis imperfecta: presentación de un caso / Osteogenesis iperfecta: report of a case

Se realiza la presentación de un caso con osteogénesis imperfecta precoz, con un cuadro clínico grave al nacimiento. Se describen las alteraciones clinicoradiológicas así como anatomopatológicas. Se señala la importancia de la detección intrauterina de esta malformación y se revisa la literatura al respecto