Unusual phenotype in a female patient with a Gly25AIa substitution in the signal peptide region of the COL2A1 gene

摘要

Clinical summary:The girl was the third child of a healthy, nonconsanguin-eous 32-year-old mother and 37-year-old father. Pregnancy was normal and delivery was at term. Congenital glaucoma, iris coloboma, and cleft palate were noted at birth. Clinical evaluation at 2 years (Fig. la) showed midface hypoplasia, micrognathia, short nose, anteverted nares, high myopia (-12 diopters), and developmental delay. At age 6 years she had bilateral retinal detachments with total visual loss. On examination at age 8 years her weight was 23 kg (25th centile), length was 111cm (< 3rd centile), and head circumference was 54.5 cm (98th centile). The facial phenotype was more marked (Fig. 1b-c) with obvious epicanthic folds, short nose, long philtrum, and full cheeks. Routine laboratory blood tests, karyotype (46,XX), and abdominal ultrasound were all normal. Audiological examination showed a moderate-to-severe bilateral mixed hearing loss. Radiographic examination at age 12 years showed thoracolumbar kyphosis, end plate irregularities, biconcave vertebral bodies, hypoplasia and wedging of the T12 vertebral body (Fig. 2), and underdevelopment of distal lateral tibial epiphyses