Spondylometaepiphyseal dysplasia, short limb-abnormal calcification type, is a rare bone dysplasia characterized by specific radiological abnormalities associated with abnormal calcification involving the epiphyses, ligaments, and chondral tissue. Other characteristics include: a narrow thorax with short flared ribs, short stature, and short limbs. Some of the patients may also have history of recurrent respiratory infection with restrictive lung disease that could result in death.
[See: Palestine > Bargal et al., 2009].
Al-Gazali et al. (1996) reported two sibs (one male and one female) with typical and radiological features of spondylometaepiphyseal dysplasia, short limb-abnormal calcification type. The parents were first cousins of Egyptian nationality. The female child presented at birth with short limbs and a large head. Skeletal survey at 2 years of age showed short long bones with wide metaphyses and well-developed radiological signs of metaphyseal and epiphyseal dysplasia. She appeared to be very intelligent, attending normal school in the appropriate grade and was top in her class. At 8 years of age, X-ray of the skull showed a wide anterior fontanelle and open posterior fontanelle. In the pelvis, there were flared iliac wings with a short basilar part, convex lower margins and short sciatic notches. All tubular bones appeared short and broad. In the hands and feet, the tubular bones were short and broad with diaphyseal constriction. The thorax was narrow, with short ribs that showed anterior flaring. The male child appeared normal at birth (according to the parents). At 6 months of age, he had a large head and small hands. At 1 year of age, abnormal eye movements were noted. At 4 years of age, eye examination revealed pendular nystagmus and bilateral optic atrophy. The child had normal intelligence, but his speech was not clear and his voice was peculiar. There were no brain or orbit abnormalities on CT scan. The bone changes in this child were very similar to those of his sister, but the degree of calcification and stippling of the epiphyses was more extensive. The vertebral bodies appeared pear shaped with wide intervertebral spaces. In the thoracolumbar spine, vertebral bodies were oval shaped with a centrally and anteriorly located bony protrusion. The thorax was narrow with extensive costonchoral calcifications. There were wide iliac wings with convex upper acetabular margins and separated ossification of the lateral bodies of the sacral bones. All the tubular bones were short with broad, flared metaphyses. The phalanges were triangular in shape. In 1999, Dawson et al. re-assessed and evaluated the radiological findings of the eldest (female) patient of Al-Gazali et al. (1996). The girl showed no finger clubbing, although her fingers were broad and short. Her chest had an increased anteroposterior diameter and a pidgeon deformity. High resolution scanning of her chest revealed evidence of fibrosis which appeared as a mosaic perfusion pattern involving segments of the upper, middle, and lower lobes. The child was dyspneic at rest with a panting type of respiration and utilized her abdominal muscles predominantly.
Ali et al. (2010) undertook mutation analysis in the patients reported by Al-Gazali et al. (1996) and detected a missense mutation, c.2254C>T (p.R752C), in the DDR2 gene in affected patients.
Bargal et al. (2009) studied six patients with SMED-SL belonging to five unrelated Arab Muslim families from the Jerusalem area. Homozygosity mapping on these and another affected patient from Algeria identified a 2.4 Mb candidate region on chromosome 1q, which included the DDR2 gene. Sequencing of this gene identified a single missesnse mutation c.2254C>T (p.R752C), in all six patients from Jerusalem and another missense mutation, c.2177 T>G (p.I726R), in an Algerian patient.
[See also: Egypt > Al-Gazali et al. (1996); Dawson et al. (1999)].