Spondylometaphyseal dysplasia with cone-rod dystrophy

Abstract

The co-occurrence of skeletal dysplasia and ophthalmologic abnormality is extremely rare. We report on a boy of a unique form of spondylometaphyseal dysplasia associated with cone-rod dystrophy. He presented with postnatal severe short stature, progressive lower limb deformity with rhizomelic shortening of the long bones, prominent joints with limited mobility in knees and elbows, mild thoracic scoliosis, and vision impairment due to cone dystrophy. Correction of deformity and simultaneous limb lengthening was performed in bilateral femora and tibiae without major complications. Skeletal manifestations in addition to comprehensive ophthalmologic examinations were described in this patient who had been followed from infancy to 16 years of age.

Mutations in PCYT1A Cause Spondylometaphyseal Dysplasia with Cone-Rod Dystrophy

“…1 It has been reported in nine families and is characterized by normal cognition, severe short stature, progressive bowing of the lower limbs, platyspondyly, metaphyseal irregularity, and cone-rod dystrophy causing visual impairment (Table S1 available online). [2][3][4] The genetic defect that causes SMD-CRD is unknown.…”

Mutations in PCYT1A, Encoding a Key Regulator of Phosphatidylcholine Metabolism, Cause Spondylometaphyseal Dysplasia with Cone-Rod Dystrophy

“…Delineated clinically a decade ago, SMD-CRD is a presumed autosomal-recessive disorder with postnatal growth deficiency leading to profound short stature; rhizomelia with bowing of the lower extremities; platyspondyly with anterior vertebral protrusions; progressive metaphyseal irregularity and cupping with shortened tubular bones; and early-onset, progressive visual impairment associated with a pigmentary maculopathy and electroretinographic evidence of cone-rod dysfunction. [2][3][4][5] In contrast to retinitis pigmentosa, the CRDs have early involvement of cone photoreceptors. 6 Here, we report loss-of-function mutations in PCYT1A (MIM 123695) as the cause of SMD-CRD.…”

“…Six of the subjects have been described in previous publications. 2,5 Subject 1 (BH2265_1; family 1; Figure 2A) was reported when she was 20 years old. 2 Now age 29, she has done well with continued linear growth to an adult height of 93.9 cm (À10.7 SD) and modest progression of limitation of range of motion.…”

Axial spondylometaphyseal dysplasia with retinitis pigmentosa—a clinical report and diagnostic clues

“…There are five well-described distinct entities; these include SMD-Kozlowski (SMD-K), SMD-corner fracture type (SMD-CF), SMD-Sedaghatian, and a recently delineated SMD associated with cone–rod dystrophy (SMD-CRD; Kitoh et al 2011). The International Skeletal Dysplasia Society Nosology Group recently included a type of SMD termed SMD with retinal degeneration, axial type.…”