Case No. :	26
Month :	February
Year :	2001
Contributor :	Dr. Zarine Shah

Case Report | Discussion | Radiological Features | Differential Diagnosis

Case report:

Clinical Features:
A three-year-old child came to our hospital with the complaints of "a large depression in the front of the skull". The mental status and developmental milestones were normal. The child was otherwise clinically asymptomatic. Her older sib had similar complaints. Both children could touch their shoulders under their chin (Fig 1).

Radiographs of the skull and chest were then performed (Fig 2, 3, 4).

A routine skull radiograph frontal and lateral views shows an open anterior fontanelle and presence of Wormian bones. The chest radiograph shows absence of both clavicles. These findings on radiography led to the diagnosis of Cleidocranial dysplasia. The patient also had this abnormality. The three-year-old also had severe dental abnormalities. All these clinical findings with radiological evidence to support it helped to reach the diagnosis of Cleidocranial dysplasia.

Discussion:

Synonyms:
Scheuthauer-Marie-Sainton syndrome
Cleidocranial dysostosis
Mutational dysostosis
Osteodental dysplasia
Pelvicocleidocranial dysplasia .

Mode of inheritance:
Autosomal dominant
Spontaneous mutation in one third of cases.
Autosomal recessive- rare.

Incidence:
0.5 in 1,00,000

Clinical features:
The typical individual presents with a large head, small face and drooping shoulders. Height is reduced but there is no dwarfism. The chest is narrow or cone shaped. Thoracic cage abnormality in the newborn can lead to respiratory distress. Delayed closure of sutures of the skull is noted in infancy. The mental status is normal. Gait disturbances and abnormal dentition in the form of delayed dental eruption, supernumerary teeth and dental impaction is seen. Hearing loss is a feature due to structural abnormality of ossicles. Extreme mobility of shoulders is noted due to clavicular hypoplasia. Often, the patient can touch the two shoulders together under the chin.

Radiologic Features :

The features of Cleidocranial dysplasia on palin radiographs are diagnostic and leave little scope for differential diagnosis.

Skull :
Brachycephalic skull - increased biparietal diameter, frontal bossing.
Multiple sutural i.e. Wormian bones.
Persistence of metopic suture.
Deformed foramen magnum.
Platybasia.
Steep vertical clivus
Hypoplastic sphenoid bone.
Hypoplastic facial bones, broad mandible and prognathism.

Spine :
Persistence of synchondrosis between vertebral bodies and neural arches.
Spina bifida occulta, especially in cervical and upper thoracic region.
Kyphosis, scoliosis, increased lumbar lordosis.
Biconvex vertebral bodies.
Hemivertebrae.

Thorax:
Anomalous development of clavicles.
The clavicle is formed from 3 separate ossification centers (sternal, middle and acromial).Any one of these can be affected.
10% - complete absence of clavicle.
Pseudoarthrosis with absence of middle portion.
Short ribs with prominent downward slope
Lack of normal ossification of the sternum
Small scapulae which may be winged or elevated.

Pelvis:
Absence or delayed ossification of pubic bones with wide pubic symphysis in adults.
Underdeveloped vertical, hypoplastic iliac wings.
Coxa varus, coax valgus.
Lateral notching of capital femoral epiphysis.

Extremities: Marked changes are seen in the hands with accessory epiphysis for the base of the second metacarpal causing elongated digit. Hypoplasia of the distal phalanges. Long bones are less frequently involved, but shortening of the radius with an abnormal wrist articulation is seen.

Complications:
Hearing loss
Dental problems
Dislocation of shoulders and hips
Scoliosis

Prenatal diagnosis:
USG- Clavicular defect
Pubic bone defects
Abnormal skull echoes

Differential diagnosis:

1.Pyknodysostosis-Clinically it is a short limbed dwarfism. Radiologically, there is generalised osteosclerosis with presence of brittle bones, pathologic fractures, fracture of vertebral arches, hangman's fracture. Clavicular hypoplasia may be present.

2.Congenital clavicular hypoplasia (congenital pseudoarthrosis of clavicle)-- Seen exclusively on the right side, it may be bilateral in 10% of cases. Seen in the first few months of life due to a painless lump over the middle third of the clavicle. Radiologically-the medial end of the clavicle is superior to the lateral end; osseous discontinuity is seen and there is callus formation.

3. Mandibuloacral dysplasia-Clinically; atrophic skin; poikiloderma; nail dysplasia; alopecia; broad short phalanges;short stature; stiff joints; insulin resistant diabetes mellitus. Radiologically: Acroosteolysis; Clavicular hypoplasia; rib hypoplasia; soft tissue calcification.

4.Craniomandibular dermatodysostosis :

5.Osteogenesis imperfecta-osseous fragility; blue sclera; hearing loss. Clavicular abnormality is not a feature of osteogenesis imerfecta

6.Hypophosphatasia-Clinically :globular boneless skull; severe deformity and shortness of limbs. Anorexia, vomiting, PUO, irritability, convulsions, cyanotic spells may be seen. Lab. Findings: Deficient activity of tissue non-specific (liver/bone/kidney) isoenzyme of alkaline phosphatase. Radiology-Failure to observe a fetal head by 16 weeks of gestation; increased echogenicity of the falx cerebri with poor mineralisation of the skull.

7.Yunis-Varon syndrome-Clinically: Dolichocephalic skull with wide fontanelles. Clavicular agenesis or hypoplasia; absent thumbs, distal aphalyngia. Progressive growth retardation and death in infancy, cardiomyopathy (arrhythmia), congenital heart disease (tetralogy). Radiologically: distal aphalangia of the hands and feet, other phalyngeal hypoplasia, cardiomegaly.

8.Scapulo-iliac dysostosis-Clinically :microphthalmos ; ectopic pupils ; coloboma of retina ; corneal opacification ; low set ears ; micrognathia. Radiology : hypoplasia of the scapula and ilium ; hypoplaisa of clavicle ; micrognathia ; synostosis of the distal portions of the clavicles to the scapulae.