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2012-10-13-16 Platyspondylic lethal skeletal dysplasia ©Fabrice Cuillier

Platyspondylic lethal skeletal dysplasia

 Fabrice Cuillier1, Mardamootoo D. 1, Dr Alessandri J.L.2, Dr Scemama J.M.3, Dr Chance P.3  
1 Service de Gynécologie, Hôpital F. Guyon, 97400 Saint-Denis, Réunion, France. 
2 Service de Néonatologie, Hôpital F. Guyon, 97400 Saint-Denis, Réunion, France. 
3 Cabinet de Radiologie, 97400 Saint-Paul, Réunion, France.   


Lethal chondrodysplasia (CDD) or platyspondylic (PLSD) are heterogeneous groups, with thanatophoric dysplasia (TD) and some variants, as PLSD type San Diego (PLSD-SD), Torrance (PLSD-T) and Luton (PLSD-L) (or platyspondylic nanism type San Diego, Torrance ou Luton). 
Thanatophoric dysplasia is divided in 2 groups (TD1 and TD2), according to clinical, radiological and biochimical factors (in particular, Fibroblast Growth factors Receptors 3 (FGFR3) mutation). Thanatophoric dysplasia variants are different due to radiological and chondro-osseous criteria. Platyspondylic lethal skeletal dysplasia are severe disorders of bone growth. Patients with this illness have very short arms and legs, a small chest with short ribs, underdevelopped pelvic bones and unusually short fingers and toes, called brachydactyly. This disorder is also characterized by flattened spinal bones (platyspondyly) and abnormal curvature of the spine.   

In this article, we describe a case of thanatophore dysplasia type 1

Case report:

A 26-year-old patient was referred for a second opinion at 21 weeks. The couple was nonconsanguineous. Her husband was 58 years old. He has four healthy children. 
At 13 weeks, the nuchal translucency was 1 mm. The triple test was not performed.
At 20 weeks, we found that the upper and lower limbs were very short, and other ultrasound findings were:
  • Macrocrania (Figure 1, 2), normal facial profile (Figure 3, 4): The facial profile didn’t show frontal bossing. Achondroplasia and achondrogenesis were eliminated.  
  • Micromelia of upper and lower limbs without hexadactyly was confirmed on 2D and 3D ultrasound with bilateral curved femur. 
  • Clavicles were normal. Cleido-cranien chondrodysplasia was excluded.  
  • 3D thoracic sonography confirmed the presence of the scapula which appeared normal (Figure 20-21). 
  • Narrow thorax 
  • 3D sonography of the pelvis showed normal iliac bones without inferior spines (Figure 23-26).    
  • A platyspondy was suspected. There were 12 ribs.   

Our diagnosis was thanatophoric dysplasia type I. Thanatophoric dysplasia type II was eliminated because clovercleaf was absent. Interruption of pregnancy was done. Postmortem examination confirmed platyspondylic chondrodysplasia, with high intervertebral space level on radiography (Figure N°12A, 12B). The autopsy was refused. Limbs were short and rhizomelic without wide metaphysis. The thorax was narrow, with broad short ribs (« en palette »). 
The final diagnosis was lethal nanism platyspondylic, thanatophoric dysplasia type I.

Figure 1, 2 : 
3D sagital sonography view of the face and 2D transverse view of the cranium (macrocrania) at 21 weeks. 

Figure 3, 4 :  
Facial profile on 2D and 3D at 22 weeks 

Figure 5, 6 : 
2D sonography view of the long bones showing micromelia.  

Figure 7-9 : 
3D sonography view of the hands and the upper limbs at 22 weeks. 

Figure 10-13 : 
2D sonography view of the inferior long bones, showing bilateral curved femur.  

Figure 14-15 : 
3D sonography view of the inferior long bones.  

Figure 16-19 : 
2D sonography view of the normal clavicle at 22 weeks.

Figure 20, 21:  
Posterior 3D view of the spine and the shoulder blade at 22 weeks showing platyspondyly and normal scapula.  

Figure 22 : 
2D transverse view of the thorax and abdomen at 22 weeks. 

Figure 23-26 : 
3D views of the iliac bones. 

Figure 27, 28 : 
3D views of the spines and the two scapulas. 

Video Clip: 

Figure 29, 30, 31, 32 : 
Biometry of the fetus up to 22 weeks of femur, humerus, radius and tibia, respectively. 

Figure 33 : Growth chart of biparietal diameter and head circumference; 
"x" indicates BPD; point (.) indicate HC

Figure 34 : 
Postmortem view of the baby.  

Figure 35, 36: 
Postmortem skeletal radiography. 


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