Osteogénesis Imperfecta / Osteogenesis Imperfecta

La osteogenesis imperfecta (OI) es un grupo de trastornos del tejido conectivo que genera anomalías esqueléticas caracterizadas por fragilidad y deformidades óseas. Las características genéticas son variables y se han descrito nuevos subgrupos los últimos años agregando información a las clasificaciones tradicionales. Su incidencia es de 1/10.000 a 20.000 RN vivos. Existe un amplio espectro de manifestaciones clínicas, que van desde una leve fragilidad ósea, en niños asintomáticos, hasta versiones que son letales al momento de nacer. El diagnóstico es principalmente clínico y debe diferenciarse de otras anomalías del esqueleto que producen fragilidad y de lesiones por maltrato infantil. El tratamiento es multidisciplinario y está orientado a mejorar la calidad de vida de los pacientes. Para lo que se debe mejorar la densidad ósea, a través de medicamentos, buena musculatura y cargas fisiológicas. Las fracturas se tratan con períodos cortos de inmovilización y carga precoz, o con cirugías que limiten el tiempo de inmovilización. Por otro lado, las deformidades esqueléticas deben tratarse en forma quirúrgica utilizando osteosíntesis que sean extensibles y mantengan la corrección a medida que el niño crece. El manejo coordinado de los distintos profesionales involucrados es de gran importancia para lograr los mejores resultados en esta enfermedad crónica que involucra al niño y todo su entorno

Osteogenesis Imperfecta (OI) is a group of connective tissue disorders involved in skeletal abnormalities characterized by bone fragility and deformities. Genetic abnormalities are variable and new subgroups have been described recently, adding information to traditional classifications. There is a wide spectrum of clinical manifestations, ranging from mild bone fragility, in otherwise asymptomatic children, to versions that are lethal at birth. Its incidence is 1/10.000-20.000 newborns. The diagnosis is mainly clinical and must be distinguished from other skeletal abnormalities and child abuse. The treatment is multidisciplinary, and it is aimed to improve the quality of life of patients. For which the bone density must be improved, through medications, strong musculature, and physiological loads. Fractures are treated by immobilizing for short periods, trying to load at soon as possible, or by surgeries that limit immobilization time. On the other hand, skeletal deformities should be treated surgically using dynamic rods that are extensible and maintain correction as the child grows. The coordinated management of the different professionals involved is of the utmost importance to achieve the best results in this chronic disease that involves the child and his entire environment

Increased cochlear otic capsule thickness and intracortical canal porosity in the oim mouse model of osteogenesis imperfecta.

Osteogenesis imperfecta (OI or brittle bone disease) is a group of genetic disorders of the connective tissues caused mainly by mutations in the genes encoding collagen type I. Clinical manifestations of OI include skeletal fragility, bone deformities, and severe functional disabilities, such as hearing loss. Progressive hearing loss, usually beginning in childhood, affects approximately 70% of people with OI with more than half of the cases involving the inner ear. There is no cure for OI nor a treatment to ameliorate its corresponding hearing loss, and very little is known about the properties of OI ears. In this study, we investigate the morphology of the otic capsule and the cochlea in the inner ear of the oim mouse model of OI. High-resolution 3D images of 8-week old oim and WT inner ears were acquired using synchrotron microtomography. Volumetric morphometric measurements were conducted for the otic capsule, its intracortical canal network and osteocyte lacunae, and for the cochlear spiral ducts. Our results show that the morphology of the cochlea is preserved in the oim ears at 8 weeks of age but the otic capsule has a greater cortical thickness and altered intracortical bone porosity, with a larger number and volume density of highly branched canals in the oim otic capsule. These results portray a state of compromised bone quality in the otic capsule of the oim mice that may contribute to their hearing loss.

Mechanisms of Bone Fragility: From Osteogenesis Imperfecta to Secondary Osteoporosis.

Bone material strength is determined by several factors, such as bone mass, matrix composition, mineralization, architecture and shape. From a clinical perspective, bone fragility is classified as primary (i.e., genetic and rare) or secondary (i.e., acquired and common) osteoporosis. Understanding the mechanism of rare genetic bone fragility disorders not only advances medical knowledge on rare diseases, it may open doors for drug development for more common disorders (i.e., postmenopausal osteoporosis). In this review, we highlight the main disease mechanisms underlying the development of human bone fragility associated with low bone mass known to date. The pathways we focus on are type I collagen processing, WNT-signaling, TGF-ß signaling, the RANKL-RANK system and the osteocyte mechanosensing pathway. We demonstrate how the discovery of most of these pathways has led to targeted, pathway-specific treatments.

A cryptic balanced translocation involving COL1A2 gene disruption cause a rare type of osteogenesis imperfecta.

BACKGROUND: Osteogenesis imperfecta (OI) is a group of hereditary disorders characterized by low bone mass and recurrent fractures. Most OI cases follow an autosomal dominant pattern of inheritance and are attributed to mutations in genes encoding type I collagen (COL1A1/COL1A2). Genomic structural variations involving type I collagen genes are extremely rare in OI. CASE REPORT: In this study, we characterized a de novo balanced translocation of t(5;7)(q32;q21.3) that caused an extremely rare type of OI in a patient from a non-consanguineous family. The clinical phenotypes of this OI included recurrent fractures, low bone mass, macrocephaly, blue sclera and failure to thrive. Next-generation sequencing was used to identify the translocation, and Sanger sequencing was used to validate and map the breakpoints. The breakpoint on chromosome 7 disrupted the COL1A2 gene in the 17th exon, presumed to affect type I collagen production and give rise to OI. The breakpoint on chromosome 5 disrupted the protein phosphatase 2 regulatory subunit B, beta gene (PPP2R2B) within the first intron. CONCLUSIONS: This is the first report of a copy-neutral structural variant involving COL1A2 that leads to a rare type of OI. This study expands the genotypic spectrum of OI and demonstrates the effectiveness of targeted sequencing for breakpoint mapping.

Cesarean delivery is not associated with decreased at-birth fracture rates in osteogenesis imperfecta.

PURPOSE: Osteogenesis imperfecta (OI) predisposes to recurrent fractures. Patients with the moderate to severe forms of OI present with antenatal fractures, and the mode of delivery that would be safest for the fetus is not known. METHODS: We conducted systematic analyses of the largest cohort of individuals with OI (n = 540) enrolled to date in the OI Linked Clinical Research Centers. Self-reported at-birth fracture rates were compared among individuals with OI types I, III, and IV. Multivariate analyses utilizing backward-elimination logistic regression model building were performed to assess the effect of multiple covariates, including method of delivery, on fracture-related outcomes. RESULTS: When accounting for other covariates, at-birth fracture rates did not differ based on whether delivery was by vaginal route or by cesarean delivery (CD). Increased birth weight conferred higher risk for fractures irrespective of the delivery method. In utero fracture, maternal history of OI, and breech presentation were strong predictors for choosing CD. CONCLUSION: Our study, the largest to analyze the effect of various factors on at-birth fracture rates in OI, shows that CD is not associated with decreased fracture rate. With the limitation that the fracture data were self-reported in this cohort, these results suggest that CD should be performed only for other maternal or fetal indications, not for the sole purpose of fracture prevention in OI.Genet Med 18 6, 570-576.

Biomecánica de las fracturas por stress / Biomechanical features of stress fractures

Se define como estrés (stress) tanto la fuerza que una carga externa ejerce sobre un cuerpo sólido como la fuerza reactiva que acompaña a la primera (Ley de Newton), por unidad de área imaginaria transversal a su dirección. Las cargas internas reactivas inducen deformaciones proporcionales del cuerpo. La resistencia del cuerpo a deformarse se llama rigidez. La deformación puede resquebrajar el cuerpo y, eventualmente, producir una fractura por confluencia de trazos. La resistencia del cuerpo a separarse en fragmentos por esa causa se llama tenacidad. La resistencia del cuerpo a la fractura es proporcional al stress que puede soportar sin separarse en fragmentos por deformación (no hay fractura sin deformación y sin stress previo). El stress máximo que un cuerpo puede soportar sin fracturarse resulta de una combinación de ambas propiedades: rigidez y tenacidad, cada una con distintos determinantes biológicos. Una o varias deformaciones del cuerpo pueden provocarle resquebrajaduras sin fracturarlo. La acumulación de resquebrajaduras determina la "fatiga" del material constitutivo del cuerpo, que reduce su rigidez, tenacidad y resistencia a la fractura para la próxima ocasión ("fragilidad por fatiga"). En el caso de los huesos, en general, los términos stress y fatiga tienen las connotaciones amplias referidas, respecto de todas las fracturas posibles. La fatiga predispone a fracturas a cargas bajas, que se denominan (correctamente) "fracturas por fatiga" y también (incorrectamente) "fracturas por stress", para distinguirlas de las que ocurren corrientemente, sin resquebrajaduras previas al trauma, que se denominan (incorrectamente) "fracturas por fragilidad, o por insuficiencia". En realidad, todas las fracturas se producen por stress y por fragilidad o insuficiencia (en conjunto); pero la distinción grosera entre fracturas "por fatiga, o por stress", por un lado, y "por fragilidad" o "por insuficiencia", por otro, aceptando las amplias connotaciones referidas antes, tiene valor en la práctica clínica. Este artículo intenta explicar esas particularidades biomecánicas y describir las distintas condiciones que predisponen a las fracturas "por fatiga o por stress" en la clínica, distinguiéndolas de las fracturas "por fragilidad o por insuficiencia" (manteniendo estas denominaciones) y detallando las características de interés directo para su diagnóstico y tratamiento. (AU)

The term "stress" expresses the force exerted by an external load on a solid body and the accompanying, opposed force (Newton's Law), expressed per unit of an imaginary area perpendicular to the loading direction. The internal loads generated this way deform (strain) proportionally the body's structure. The resistance of the body to strain expresses its stiffness. Critical strain magnitudes may induce micro-fractures (microdamage), the confluence of which may fracture the body. The body's resistance to separation into fragments determines its toughness. Hence, the body's resistance to fracture is proportional to the stress the body can support (or give back) while it is not fractured by the loadinduced strain (no stress, no strain -> no fracture). Therefore, the maximal stress the body can stand prior to fracture is determined by a combination of both, its stiffness and its toughness; and each of those properties is differently determined biologically. One or more deformations of the body may induce some microdamage but not a fracture. Microdamage accumulation determines the fatigue of the material constitutive of the body and reduces body's toughness, leading to a "fatigue-induced fragility". In case of bones, in general, both stress and fatigue have the referred, wide connotations, regarding any kind of fractures. In particular, bone fatigue predisposes to low-stress fractures, which are named (correctly) "fatigue fractures" and also misnamed "stress fractures", to distinguish them from the current fractures that occur without any excess of microdamage, that are named (wrongly) "fragility" or "insufficiency" fractures. In fact, all fractures result from all stress and fragility or insufficiency as a whole; however, the gross distinction between "fatigue or stress fractures", on one side, and "fragility or insufficiency fractures", on the other, accepting the wide connotations of the corresponding terminology, is relevant to clinical practice. This article aims to explain the above biomechanical features and describe the different instances that predispose to "fatigue or stress fractures" in clinical practice, as a different entity from "insufficiency or fragility fractures" (maintaining this nomenclature), and describe their relevant features to their diagnosis and therapy. (AU)

An osteogenesis imperfecta case with breast cancer.

Osteogenesis imperfecta (OI) is a rare connective tissue disease characterized by abnormalities of type 1 collagen and an increased risk of bone fractures. Several OI cases with malignancies have been reported. Herein, we describe an OI case with breast cancer. A 36-year-old premenopausal woman with OI was admitted to our hospital for evaluation of a right breast lump. We diagnosed right breast cancer with axillary and parasternal lymph node metastasis (T2N3M0 stage IIIC). The tumor had increased in size and tumor markers were elevated after 10 months of hormone therapy. We performed a right mastectomy and axillary dissection. She subsequently received adjuvant chemotherapy and radiotherapy. She is currently taking trastuzumab and tamoxifen. Anesthesia is challenging in OI patients because of difficulty with airway control and intubation. We performed the mastectomy in this case without difficulty by working in cooperation with experienced anesthesiologists, orthopedists, and other medical personnel. Some OI patients reportedly have severe 5-fluorouracil (5-FU) toxicity related to dihydropyrimidine dehydrogenase (DPD) deficiency. DPD is the main enzyme involved in the catabolism of 5-FU. Our present case also had low DPD activity and we thus chose epirubicin and cyclophosphamide for chemotherapy. Our search of the literature yielded only two OI cases with breast cancer as of April 2011. To our knowledge, this is the first case reported in Japan.

[Clinical condition and therapy of bone diseases].

Skeletal dysplasia is the term which represents disorders including growth and differentiation of bone, cartilage and ligament. A lot of diseases are included, and new disorders have been added. However, the therapy of most bone diseases is less well-established. Achondroplasia, hypochondroplasia, and osteogenesis imperfecta are most frequent bone diseases. There is no curative treatment for these diseases, however, supportive therapies are available ; for example, growth-hormone therapy for achondroplasia and hypochondroplasia, and bisphosphonate therapy for osteogenesis imperfecta. In addition, enzyme replacement therapy for hypophosphatasia is now on clinical trial.

Osteogénesis imperfecta: caso clínico / Osteogenesis imperfecta: report of a clinical case

Las displasias esqueléticas son un grupo de enfermedades de los huesos, de origen genético, tipo generalizado. Son enfermedades poco frecuentes. Se han descrito aproximadamente 350 tipos de displasias óseas diferentes. Dentro de éstas, se encuentra la osteogénesis imperfecta, en la que hay una alteración del colágeno tipo 1. Este colágeno se encuentra también en la conjuntiva, en los ligamentos y en los dientes; de allí que las manifestaciones pueden observarse también en áreas extraóseas. En el caso clínico, se describe la situación de una paciente pediátrica con diagnóstico de osteogéensis imperfecta tipo 1, la problemática de la enfermedad y las posibilidades de tratamiento odontológico.(AU)

Osteogénesis imperfecta: caso clínico / Osteogenesis imperfecta: report of a clinical case

Las displasias esqueléticas son un grupo de enfermedades de los huesos, de origen genético, tipo generalizado. Son enfermedades poco frecuentes. Se han descrito aproximadamente 350 tipos de displasias óseas diferentes. Dentro de éstas, se encuentra la osteogénesis imperfecta, en la que hay una alteración del colágeno tipo 1. Este colágeno se encuentra también en la conjuntiva, en los ligamentos y en los dientes; de allí que las manifestaciones pueden observarse también en áreas extraóseas. En el caso clínico, se describe la situación de una paciente pediátrica con diagnóstico de osteogéensis imperfecta tipo 1, la problemática de la enfermedad y las posibilidades de tratamiento odontológico.

Dentinogénesis imperfecta tipo I / Dentinogenesis imperfecta, type I

La dentinogénesis imperfecta (DI) es una anomalía dentaria determinada genéticamente y caracterizada clínicamente por una apariencia ámbar opalescente de la dentina. Se presenta la resolución clínica, con seguimiento y control a 3 años, de un paciente con diagnóstico de DI. La identificación temprana de esta entidad y el tratamiento oportuno y multidisciplinario, contribuyen a mejorar el pronóstico de la misma.

New perspectives on osteogenesis imperfecta.

A new paradigm has emerged for osteogenesis imperfecta as a collagen-related disorder. The more prevalent autosomal dominant forms of osteogenesis imperfecta are caused by primary defects in type I collagen, whereas autosomal recessive forms are caused by deficiency of proteins which interact with type I procollagen for post-translational modification and/or folding. Factors that contribute to the mechanism of dominant osteogenesis imperfecta include intracellular stress, disruption of interactions between collagen and noncollagenous proteins, compromised matrix structure, abnormal cell-cell and cell-matrix interactions and tissue mineralization. Recessive osteogenesis imperfecta is caused by deficiency of any of the three components of the collagen prolyl 3-hydroxylation complex. Absence of 3-hydroxylation is associated with increased modification of the collagen helix, consistent with delayed collagen folding. Other causes of recessive osteogenesis imperfecta include deficiency of the collagen chaperones FKBP10 or Serpin H1. Murine models are crucial to uncovering the common pathways in dominant and recessive osteogenesis imperfecta bone dysplasia. Clinical management of osteogenesis imperfecta is multidisciplinary, encompassing substantial progress in physical rehabilitation and surgical procedures, management of hearing, dental and pulmonary abnormalities, as well as drugs, such as bisphosphonates and recombinant human growth hormone. Novel treatments using cell therapy or new drug regimens hold promise for the future.

Mutation characteristics in type I collagen genes in Chinese patients with osteogenesis imperfecta.

Osteogenesis imperfecta is normally caused by an autosomal dominant mutation in the type I collagen genes COL1A1 and COL1A2. The severity of osteogenesis imperfecta varies, ranging from perinatal lethality to a very mild phenotype. Although there have been many reports of COL1A1 and COL1A2 mutations, few cases have been reported in Chinese people. We report on five unrelated families and three sporadic cases. The mutations were detected by PCR and direct sequencing. Four mutations in COL1A1 and one in COL1A2 were found, among which three mutations were previously unreported. The mutation rates of G>C at base 128 in intron 31 of the COL1A1 gene and G>A at base 162 in intron 30 of the COL1A2 gene were higher than normal. The patients' clinical characteristics with the same mutation were variable even in the same family. We conclude that mutations in COL1A1 and COL1A2 also have an important role in osteogenesis imperfecta in the Chinese population. As the Han Chinese people account for a quarter of the world's population, these new data contribute to the type I collagen mutation map.

Evolution of the radiographic appearance of the metaphyses over the first year of life in type V osteogenesis imperfecta: clues to pathogenesis.

We present the first report of the development of characteristic radiologic appearances of long bones during the first year of life in an infant with type V osteogenesis imperfecta (OI). We show the evolution of metaphyseal abnormalities from a rickets-like appearance to the classically described dense metaphyseal bands. These abnormalities suggest that the underlying defect in type V OI may involve a molecule common to both bone and cartilage that is involved in the regulation of growth plate development and metadiaphyseal ossification. Our findings provide new insights into skeletal development in type V OI and potentially yield useful clues to the identity of the defect underpinning the condition.

[Prenatal diagnose of abnormalities of fetal limb bone].

OBJECTIVE: to discuss the prenatal diagnosis of abnormalities of fetal limb bone. METHODS: we selected 18 cases which long bone of fetus less than 2SD of average volume of gestational weeks or long bone changed into angle or other fetus's abnormalities by first B-mode ultrasonic. All above cases was delivered at Capital Medical University of Obstetric and Gynecological Hospital during Jan. 2006 to Dec. 2009. We B-mode ultrasonic was used to measure fetus's biparietal diameter (BPD), femur length (FL), abdominal circumference (AC), head circumference (HC), humerus length (HL), amniotic fluid index (AFI) and structures of organ and calculated FL/AC, growth speed of long bone. The standard of achondroplasia is that FL and HL are less than 4SD of average of gestational weeks or FL/AC less than 0.16. The standard of Osteogenesis Imperfecta is fetal long bone of fetus shows short and thick, curves into angle, fracture in uterus by X-ray, or skull shows thin or sink by X-ray. RESULTS: (1) by B-mode ultrasonic and X-ray exam of all 18 cases: 7 cases shows that HC > 2SD, 10 cases shows too much amniotic fluid, 12 cases shows AFI > 18.0, 9 cases shows abnormalities of narrow cavitas thoracis, disordered vertebral column, or unusual architecture of heart. For cases 1 to 14 are achondroplasia, among which, 11 cases are FL < 4SD and HL < 4SD, 2 cases are FL < 3SD and HL < 4SD, 1 case is not only FL < 2SD and HL < 3SD but also hydroncus all over the body of fetus. The growth velocity of long bone of fetus in all the 14 cases is more slowly than the normal rate. For all the above 14 cases, 12 cases FL/AC < 0.16, 1 case FL/AC = 0.19, 1 case FL/AC = 0.20. The length of femur or humerus is shorter than the normal rate and have other abnormalities the above last two cases. For case 15 and 16, they don't show any abnormalities of bone growth though one year's follow up studying. For case 17 and 18, they are osteogenesis imperfecta. (2) The result of fetal perinatal period fate and autopsy: there are 8 female and 10 male in all the 18 cases. One case is labored after 39 weeks pregnancy, and it is low birth weight infant, weight < 3%th. All the other cases are normally birth weight infant. All the 18 cases of abnormalities of fetal limb bone are examined by chromosomes check, among which, 9 cases are amniocentesis, 7 cases are cordocentesis, 2 cases are checked chromosomes by fetus cord blood, all the caryotype are normal. In the 16 autopsy cases, 14 cases are achondroplasia or hypochondroplasis. It can be seen amplifying extremities, hyperplasia chondrocytes of tubiform born, karyomegaly, anachromasis, hyperplasia capillaries though microscope and grow up into cartilage irregularly. Also can be seen hyperplasia chondrocytes of epiphyses, delaying osteosis. 2 cases are osteogenesis imperfecta. It can be seen broadening of metaphyses, exility of bone trabeculae. For the other two cases which the fetus is alive, we do the follow up studying to their one year old one of them is low birth weight new born, their limb and height are all normal. CONCLUSIONS: to diagnose fetal Achondroplasia, it is not only based on the significantly shorter of femur or humerus length but also based on the dynamics observing the long bone growth velocity and calculating FL/AC. For osteogenesis imperfecta fetus, it should be diagnosed by fractures in uterus though X-ray.

A case of Mollitias and Fragilitas Ossium - unusual presentation of hairy cell leukaemia followed by the diagnosis of nonsecretory myeloma.

Hairy cell leukaemia (HCL) is a B-cell malignancy with a late developmental arrest. This report describes a patient that presented with leucocytosis and splenomegaly. The abnormal leucocytes showed typical morphology and expressed CD103, CD11c, CD19 and CD20 but not CD25 by immunophenotyping. The patient failed to respond to splenectomy and then developed lytic bone lesions and pathological fractures, which progressed despite a single course of cladribine chemotherapy. Review of the pathology of the bone reamings showed nonsecretory myeloma of the same kappa-light chain isotype. He went on to receive induction chemotherapy in preparation for an autologous stem-cell transplant but failed to mobilize sufficient numbers of stem cells. He has had two localized relapses with bony lesions, one within 6 weeks of stopping chemotherapy for which he received localized radiotherapy and thalidomide consolidation. Sequential myeloma has been described in HCL. There is controversy whether this represents clonal evolution or a secondary malignancy. An increased rate of secondary malignancies has been reported by some, but not other, authors in long-term survivors of HCL. This case illustrates the value of a repeat pathological review in case of unexpected complications.

Osteogenesis imperfecta in the neonate.

Osteogenesis imperfecta is a rare heterozygous disorder of collagen production. It is characterized by osteopenia, blue sclera, bone deformities, and progressive hearing loss. Some infants are diagnosed prenatally, whereas others are diagnosed much later in life. This article provides an overview of the disorder and discusses the etiologic origins of the syndrome. A guide for a systematic physical assessment is presented to enhance the early recognition of the disorder. Pictorial examples are provided to enhance the understanding of the wide spectrum of osteogenesis imperfecta. A discussion on treatment and clinical implications, with an emphasis on family support, is provided.

Osteogénesis imperfecta: mosaicismo germinal o evidencia de heterogeneidad genética. Presentación de una familia y revisión bibliográfica / Osteogénesis imperfect: mosaicismo germinal or evidence of genetic heterogeneousness: presentation of a family and bibliographical review

La osteogénesis imperfecta clasifica entre las displasias óseas por alteraciones en la densidad y los defectos del modelaje óseo. El tipo I es la forma más frecuente de la enfermedad y se caracteriza por un patrón de herencia autosómico dominante. No es infrecuente que la enfermedad aparezca producto de una nueva mutación. También se ha demostrado que puede ser producida por mosaicismos germinales. Este trabajo documenta, por primera vez en Cuba, el caso de una familia con 3 individuos de diferente sexo afectados por osteogénesis imperfecta de tipo I mientras ninguno de los progenitores lo está. Se discute la posibilidad etiológica de un mosaicismo germinal y se valora asimismo la posibilidad de un patrón de herencia distinto del dominante, lo cual aportaría nueva evidencia de heterogeneidad genética(AU)

Osteogenesis imperfecta is one of the bone dysplasias caused by altered density and bone model defects. Type I is the most common form of disease and is characterized by an autosomal dominant inheritance pattern. Sometimes, this disease occurs as a result of a new mutation. It has been also demonstrated that it can be caused by germ mosaicisms. This paper documented for the first time in Cuba the case of a family with three (3) individuals of both sexes affected by type-1 osteogenesis imperfecta but their parents were not. The etiological possibilities of germ mosaicism and the possibilities of an inheritance pattern different from the dominant one were discussed, which would give new genetic heterogeneity evidence(AU)

Osteogénesis imperfecta: mosaicismo germinal o evidencia de heterogeneidad genética. Presentación de una familia y revisión bibliográfica / Osteogénesis imperfect: mosaicismo germinal or evidence of genetic heterogeneousness: presentation of a family and bibliographical review

La osteogénesis imperfecta clasifica entre las displasias óseas por alteraciones en la densidad y los defectos del modelaje óseo. El tipo I es la forma más frecuente de la enfermedad y se caracteriza por un patrón de herencia autosómico dominante. No es infrecuente que la enfermedad aparezca producto de una nueva mutación. También se ha demostrado que puede ser producida por mosaicismos germinales. Este trabajo documenta, por primera vez en Cuba, el caso de una familia con 3 individuos de diferente sexo afectados por osteogénesis imperfecta de tipo I mientras ninguno de los progenitores lo está. Se discute la posibilidad etiológica de un mosaicismo germinal y se valora asimismo la posibilidad de un patrón de herencia distinto del dominante, lo cual aportaría nueva evidencia de heterogeneidad genética.

Osteogenesis imperfecta is one of the bone dysplasias caused by altered density and bone model defects. Type I is the most common form of disease and is characterized by an autosomal dominant inheritance pattern. Sometimes, this disease occurs as a result of a new mutation. It has been also demonstrated that it can be caused by germ mosaicisms. This paper documented for the first time in Cuba the case of a family with three (3) individuals of both sexes affected by type-1 osteogenesis imperfecta but their parents were not. The etiological possibilities of germ mosaicism and the possibilities of an inheritance pattern different from the dominant one were discussed, which would give new genetic heterogeneity evidence.