Journal of Postgraduate Medicine Medknow Publications and Staff Society of Seth GS Medical College and KEM Hospital, Mumbai, India ISSN: 0022-3859 EISSN: 0972-2823 Vol. 52, Num. 1, 2006, pp. 69-70

Journal of Postgraduate Medicine, Vol. 52, No. 1, January-March, 2006, pp. 69-70

Letter To Editor

Antenatal diagnosis of camptomelic dysplasia

Nagar AM, Sangle PM, Morani AjayC, Rajpal ND

Department of Radiology, KEM Hospital, Acharya Dhonde Marg, Parel, Mumbai-400012, India

Correspondence Address: Dr. Ajay Morani, E-mail: ajaycmorani@yahoo.com

Code Number: jp06023

Sir,

Campomelic dysplasia (CD, also known as camptomelic dysplasia) is a rare skeletal dysplasia characterized by the radiological features of short and bowed femora and tibiae, absent or hypoplastic fibulae, hypoplastic scapulae and pelvic bones, and nonmineralized thoracic pedicles. Clinically, an affected infant exhibits bowed lower limbs with pretibial skin dimpling, sex reversal (75%), dolichocephaly, micrognathia, cleft palate, a flat nasal bridge, low set ears, talipes equinovarus, and congenital dislocation of the hips. Patients usually succumb in the neonatal period owing to respiratory insufficiency.[1] In almost all the cases of CD described in literature, accurate diagnosis was made postnatally. In the present paper, we describe the antenatal diagnosis.

A 22-year-old lady, normotensive, gravida 2, para 1, and living 1 with 28 weeks of gestation was referred for an ultrasound examination (USG), because clinically, the uterine size was large for gestational age. The USG revealed bowing of the long bones [Figure - 1][Figure - 2], club feet, reduced thoracic diameter, hypoplastic scapulae, hydronephrosis and polyhydramnios, consistent with the diagnosis of camptomelic dysplasia . The neonate expired within 1 hour of the birth owing to severe respiratory distress. It had ambiguous genitalia with a vaginal opening and a phallus [Figure - 3]. Babygram [Figure - 4] confirmed the skeletal abnormalities seen on antenatal sonography. The parents refused an autopsy or karyotyping of the baby.

In our case, the first abnormality picked up was short and bent femora with hydramnios. Short limbs associated with hydramnios, mentioned frequently in the literature, is a useful marker for lethal skeletal dysplasia.[2] On further screening, hypoplastic scapulae were seen, leading to the diagnosis of CD. Hypoplasia of the scapula is an important diagnostic feature of this condition, irrespective of the presence or absence of campomelia of the femora.[3] The prenatal differential diagnosis of this condition includes asphyxiating thoracic dysplasia, hypophosphatasia, osteogenesis imperfecta types 2 and 3, and unclassified varieties of congenital bowing of the long bones.[4] All these differential diagnoses were excluded by the absence of facial anomalies, bell-shaped thorax, hypoplastic scapulae, and sex reversal, which can be assessed using an ultrasound.[4]

There is significant literature in the pathogenesis of this condition. It is now believed that mutations or translocations in the gene SOX9 on the long arm of chromosome 17, result in the syndrome of CD.[1],[5],[6] These mutations only affect a single allele of SOX9, suggesting a dominant mode of inheritance for this syndrome.[1] SOX9 plays an important role in chondrogenesis and testogenesis. Three important domains on it, HMG domain, proline/glutamine/serine-rich C-terminal transcription activation domain, and dimerization domain, are needed for its function.[5] Mild forms of CD, nonlethal type, or acampomelic dysplasia are most often associated with chromosome 17 rearrangements, resulting in decreased, rather than absent, SOX9 activity,[6] or they may be owing to incomplete penetration or mosaicism of the mutant gene.[1],[5] Histological analysis of chondro-osseous tissues of the long bones of the lower extremities shows hypoplasia and scant organization of the chondrocytes in the columnar cartilage of the growth plate with increased vacuolar degeneration and scarce cytoplasmic calcification. Bony trabeculae are thin and poorly defined.[4]Though we diagnosed CD at 28 weeks of gestation (first USG), the clear visibility of femora at 13-14 weeks should enable us to make the diagnosis earlier and help in counseling of the couple and further obstetric management.

References

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