Prenatal Diagnosis of Skeletal Dysplasia and Review of the Literature

Introduction. Obstetric ultrasonography is routinely used to screen for fetal anomalies. Thanatophoric dysplasia (TD) is one of the common though rare lethal skeletal dysplasia, detected during routine ultrasound scan. TD is caused by a mutation in FGFR3 gene. Characteristic features include shortening of limbs, macrocephaly and platyspondyly. In our local setting, it is common to miss the diagnosis in the early scans due to lack of expertise of the sonographers. To the best of our knowledge, this is the first publication from Ghana. Case Presentation. We present the case of a 33-year-old woman who was referred to the facility on account of ultrasound scan report suggestive of thanatophoric dysplasia type 1 at 34 weeks of a female baby. The diagnosis was not made despite the mother being a regular antenatal attendant, until a fifth scan done at 34 weeks reported features suggestive of thanatophoric dysplasia. The ultrasound scan features included a biparietal diameter of 37weeks, femur length—24weeks, narrowed thoracic cage with hypoplastic lungs and short ribs. The liquor volume was increased with amniotic fluid index (AFI) of 38.4 cm. The femur, tibia, fibula, humerus, ulna, and radius were shortened (micromelia). The diagnosis of thanatophoric dysplasia type 1 was confirmed on autopsy. Conclusion. This report was aimed to highlight the potential contribution of ultrasound scan in the diagnosis of thanatophoric dysplasia in our setting.

Thanatophoric dysplasia- a rare cause of stillbirth and perinatal mortality: a case report

Lethal skeletal dysplasia is estimated to occur in 0.95 per 10,000 deliveries. Thanatophoric dysplasia affects about 1in 25000 to 50000 births. The term thanatophoric is Greek word for “death bearing”. Children with this condition are usually stillborn or die shortly after birth from respiratory failure. We report a case of LSD (Thanatophoric dysplasia), in an unbooked patient where previous two children and couple were absolutely normal. Our patient, 31 years old, unbooked case presented with history of amenorrhea 8 months and unable to perceive fetal movements. Her husband’s age was 33 years. This was her third pregnancy. She had previous 2 deliveries by LSCS. Ultrasonography revealed single intrauterine live fetus in breech presentation with multiple fetal anomalies. There was shortening and deformity of all four limbs (micromelia) with poor mineralization of all bones. Thorax was pear shaped with short horizontal ribs and abnormal cardiothoracic ratio. LSCS was done in emergency for impending rupture of previous LSCS scar. Post-delivery examination and X-ray of the fetus revealed decreased skull mineralization, frontal bossing, hypoplastic nasal bone, midface hypoplasia, mandibular hypoplasia, pear shaped chest, protuberant abdomen, micromelia, dumbbell shaped appearance of all long bones. TD is caused due to mutation of the fibroblast growth factor receptor 3 gene (FGFR3), which is located on the short arm of chromosome 4. Type I TD is characterized by marked underdeveloped skeleton and short-curved long bones. Conventional radiographic examination remains the most useful means of studying the dysplastic skeleton. Bony evaluation is best done on X-rays or ultrasonography. The diagnosis of TD can be established with ultrasound and molecular confirmation in the second trimester can help in genetic counselling and termination of such lethal pregnancies. LSD’s are rare event. If our patient had undergone anomaly scan in second trimester of pregnancy, this defect could have been detected earlier. The outcome of fetus is lethal but maternal morbidity can be reduced if diagnosed early.

Thanatophoric Dysplasia

Background: The term tanatophorik comes from the Greek word thanatophorus which means "innate death" or "bearing death". The problem that underlies this disease is the process of bone formation. This disease is associated with an autosomal dominant inherited mutation of the fibroblast growth factor 3 receptor (FGFR3) gene on the arm of chromosome 4 (4p16.3). Because FGFR3 is the main modulator in bone formation, the typical clinical features of this disease include shortening of the extremities, curved femur, clover-like skull and narrowing of the thoracic cavity.Tanatophoric dysplasia is a skeletal disorder that is "lethal" or deadly. The deaths occurred due to respiratory failure caused by reduced chest cavity capacity, hypoplastic lungs and / or brainstem compression.Destination: Reported a case of thanatophoric dysplasiaMethod: Case Report Case Report: Case 33 years old woman, with preterm parturient G1P0A0H0 35-36 weeks 1 latent phase + history of 2x laparotomy + suspected fetal tanatophoric dysplasia. On ultrasound examination, it was found that BPD = 9.14 cm; AC = 30.56 cm; HC = 32.05 cm; FL = 2.55 cm; AFI; 9.06cm; SDAU = 1.72 cm. The presence of frontal bosing, saddle nose and micromilia (proximal, distal, phalanges) was found. The patient was planned for vaginal delivery and the progress of labor was followed. Patients provided informed consent regarding the possibility of fetal death during labor and after birth. During the active phase of the labor process, hypotony uterine innersia occurs and oxytocin drip is performed to accelerate labor. The baby was born male, weight 2175 grams, body length 34 cm and A / S: 1/0. Postmortem physical examination revealed macroscopic findings of tanatophoric dysplasia infants such as hypertelorism, low nasal bridge, cranio-facial disproportion. Narrow chest with protruding abdomen and short, bent limbs.Conclusion: Tanatophoric dysplasia is "lethal" skeletal dysplasia. Careful prenatal examination is required in diagnosis and termination of pregnancy. Keywords: Thanatophoric dysplasia, prenatal diagnosis