Displasias esqueléticas: Reporte de un caso y revisión de la literatura / Skeletal dysplasias: Report of a case and review of the literature

RESUMEN Las displasias esqueléticas son un grupo heterogéneo de condiciones que afectan primariamente la formación y crecimiento de huesos y cartílagos, se caracterizan por un acortamiento generalizado de huesos largos. Son patologías de baja prevalencia, que se pueden diagnosticar con precisión mediante ultrasonografía del primer y segundo trimestre. La importancia de esta patología radica en que posee una letalidad cercana al 50%. La displasia esqueletica letal más frecuente es la displasia tanatofórica, la cual se caracteriza por macrocefalia con base de cráneo estrecha, tórax estrecho, cuerpos vertebrales planos, micromelia generalizada, ausencia de fracturas, ventriculomegalia, polihidroamnios y mineralización ósea normal. Debido a que la presentación de la displasia tanatoforica se debe a una mutación autosómica dominante de novo no germinal, el riesgo de recurrencia no es mayor que el de la población general. Dado su elevada letalidad no pasa a generaciones futuras.

SUMMARY Skeletal dysplasias are a heterogeneous group of conditions that primarily affect the formation and growth of bones and cartilage, characterized by a generalized shortening of long bones. These are pathologies of low prevalence, which can be accurately diagnosed by first and second trimester ultrasonography. The importance of this pathology lies in that it has a lethality close to 50%. The most common lethal skeletal dysplasia is tanophilic dysplasia, which is characterized by macrocephaly with a narrow cranial base, narrow chest, flat vertebral bodies, generalized micromelia, absence of fractures, ventriculomegaly, polyhydroamnios and normal bone mineralization. Because the presentation of the tanophoretic dysplasia is due to an autosomal dominant mutation of novo non-germinal, the risk of recurrence is not greater than that of the general population. Given its high lethality does not happen to future generations.

Diagnóstico ecográfico prenatal de displasia tanatofórica: a propósito de un caso / Prenatal diagnosis ultrasonographic thanatophoric dysplasia: report of a case

La Displasia tanatofórica es probablemente la displasia letal más común. Ocurre en aproximadamente en 0,69 por cada 10.000 nacimientos. Su etiología es posiblemente autosómica dominante y resulta de mutaciones nuevas del factor de crecimiento del receptor de los fibroblastos. La patogenia es debida a desorganización del cartílago de crecimiento con persistencia de tejido símil parenquimatoso. Es una condrodisplasia congénita letal caracterizada por el acortamiento de los miembros, hipoplasia torácica, cráneo en hoja de trébol, pliegue simiesco, fémur acortado, estrechamiento torácico, frente prominente, polo cefálico con dimensiones aumentadas aún sin ventriculomegalia y redundancia de las partes blandas.Ademásestá asociado a polihidramnios en un 70 %. Las anomalías asociadas son hidrocefalia, anomalías renales, defecto del tabique auricular, válvula tricúspide anómala, ano imperforado y sinóstosis radio cubital. Se presenta la experiencia de un caso de displasia tanatofórica que se ha podido diagnosticar con la ecografía prenatal.

Thanatophoric dysplasia is probably the most common lethal dysplasia. It occurs in about 0.69 of 10,000 births. Its etiologyis dominantand autosomal probabilly dueto new mutations from growth factor receptor fibroblasts. The pathogenesis is dueto disorganization of the growth cartilage with persistente of parenchymal like tissue. It´s a lethal congenital chondrodysplasia characterized by short limbs, thoracichypoplasia, skull cloverleaf, simiancrease, shortened femur, thoracic narrowing, prominent forehead, cephalic pole with increased dimension seven without ventriculomegaly, redundancy of the soft tissues. Also polyhydramniosis associated with in 70% of cases. The associated anomalies are hydrocephalus, kidney abnormalities, atrial septal defect, abnormal tricuspidvalve, imperforateanus which radioulnarsynostosis. The present a case with thanatophoric dysplasia which has been diagnosed with prenatal ultrasound.

Achondrogenesis: A Lethal Chondrodystrophy.

Achondrogenesis is a type of skeletal dysplasia. Skeletal dysplasias are the heterogeneous class of bone growth disorders resulting in abnormal shape and size of the skeleton. Here, we present a rare case of achondrogenesis which was delivered by induced abortion at 6½ months of gestation. The physical, radiological, and ultrasonographic examinations done raised the possibility of this very rare anomaly. Achondrogensis is characterized by extreme micromelia and marked discrepancy between the relatively large head and the decreased trunk length. This rare condition has got genetic mutations associated with it. Achondrogenesis resembles other chondrodystrophies, therefore, its diagnosis needs to be made promptly and accurately.

Thanatophoric dysplasia: a rare entity

Thanatophoric dysplasia is the lethal skeletal dysplasia characterized by marked underdevelopment of the skeleton and short-limb dwarfism. The child will be having a short neck, narrow thoracic cage and protuberant abdomen. Other anatomical features include a relatively enlarged head with frontal bossing, prominent eyes, hypertelorism and the depressed nasal bridge. The diagnosis is usually made with the ultrasonography in the second trimester. In this study we report a case of this rare entity with emphasis on its anatomical features, abnormalities and clinical profile with relevant review of literature