Diagnóstico pré-natal de displasia tanatofórica: papel do ultrassom fetal

OBJETIVO: Relatar o caso de um paciente com displasia tanatoforica, uma forma autossomica dominante e letal de nanismo, diagnosticado ainda no periodo pre-natal, e revisar a literatura, discutindo os principais diagnosticos diferenciais e ressaltando a importância do ultrassom fetal na identificacao de fetos portadores dessa displasia. DESCRICAO DO CASO: O paciente e o segundo filho de pais jovens sem historia familiar de doencas geneticas. O ultrassom fetal realizado com 35 semanas de gestacao mostrou polidrâmnio, proeminencia frontal e desproporcao entre crânio e tronco, com hipoplasia toracica e encurtamento dos ossos longos, compativel com o diagnostico de displasia tanatoforica. Ao nascimento, a crianca era pequena e possuia hipotonia, macrocefalia, fontanelas amplas, hipoplasia de face media, olhos protrusos, hemangioma plano no nariz e palpebras, nariz em sela, micrognatia, pescoco e torax curtos e encurtamento importante de bracos, antebracos, coxas e pernas. A avaliacao radiografica mostrou crânio com grande diâmetro transverso, torax com costelas curtas e corpos vertebrais reduzidos, importante encurtamento e deformidade dos ossos longos dos membros superiores e inferiores (os femures eram curvos) e hipoplasia da bacia. Esses achados confirmaram o diagnostico pre-natal de displasia tanatoforica. O paciente evoluiu para o obito poucos dias apos o nascimento devido a insuficiencia respiratoria. COMENTARIOS: A ultrassonografia fetal e um metodo nao invasivo capaz de diagnosticar inumeras displasias osseas, incluindo a tanatoforica. A importância do diagnostico intra-utero reside no fato de que auxilia no diagnostico diferencial, e permite o aconselhamento genetico a familia. OBJECTIVE: To report a patient with thanatophoric dysplasia, an autosomal dominant and lethal form of nanism diagnosed in the prenatal period and to review the literature, discussing the main differential diagnosis and highlighting the importance of the fetal ultrasound in the identification of fetus with this dysplasia. CASE DESCRIPTION: The patient is the second son of young parents without family history of genetic diseases. The fetal ultrasound performed with 35 weeks of gestation showed polyhydramnios, prominent forehead and disproportion between skull and trunk, with thoracic hypoplasia and shortening of long bones, suggestive of thanatophoric dysplasia. At birth, the child was small and presented: hypotonia, macrocephaly, large fontanel, middle face hypoplasia, bulging eyes, nevus flammeus in the nose and eyelids, low nasal bridge, micrognathia, short neck and thorax, and an important shortening of arms, forearms, thighs and legs. Radiographic evaluation showed a great transverse diameter of the skull, thorax with short ribs and diminished vertebral bodies, shortening and deformity of the long bones of upper and lower limbs (with curved femora) and hypoplasia of the pelvis. These features confirmed the prenatal diagnosis of thanatophoric dysplasia. The patient died few days after birth due to respiratory insufficiency. COMMENTS: Fetal ultrasound is a non-invasive method capable of diagnosing several bone dysplasias, including the thanatophoric one. The intrauterine diagnosis allows the differential diagnosis of the condition as well as the genetic counseling for the family.