Somatic mosaicism for the SALL1 mutation p.Ser371X in full-blown Townes–Brocks syndrome with Duane anomaly
✍ Scribed by Peter C. van den Akker; Raoul van de Graaf; Dennis Dooijes; Anthonie J. van Essen
- Publisher
- John Wiley and Sons
- Year
- 2009
- Tongue
- English
- Weight
- 281 KB
- Volume
- 149A
- Category
- Article
- ISSN
- 1552-4825
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✦ Synopsis
Here we report on a 3-year-old boy with full-blown TBS and two rare features, Duane anomaly (DA) and somatic mosaicism for the causative SALL1 mutation.
This boy is the third child of non-consanguineous parents and he was born at 39 þ6 weeks gestation as the second child of a dizygotic twin pregnancy. At birth, his weight was 2,915 g (À1 SD), length 45 cm (À2 SD), and OFC 33.5 cm (À1 SD). He presented with membranous anal atresia and pre-axial polydactyly of the right hand. Clinical inspection revealed ulnary deviation of the distal phalanges of both thumbs, with duplication of the distal phalanx of the right thumb (Fig. ). X-rays confirmed the duplication of the distal phalanx of the biphalangeal right thumb, and showed a triphalangeal left thumb and a broad distal phalanx of the right hallux (Fig. ). The helices of both ears were dysplastic and there was a pre-auricular nodule on the right side (Fig. ). Besides bilateral ptosis of the eyelids there were no facial dysmorphisms. He twice failed the neonatal hearing screening and audiologic evaluation at 2.5 years identified moderate bilateral sensorineural hearing loss (55-75 dB level). X-rays of the thorax and vertebral column showed no abnormalities. Abdominal ultrasound showed bilateral dysplastic kidneys. Vesico-ureteral reflux and renal insufficiency were discovered later. Echocardiography shortly after birth revealed a hemodynamically unimportant, persistent ductus, but no structural heart defect. On the right hemithorax, he has a large capillary malformation that crosses the midline on his back and does not follow an anatomical pattern (Fig. ). As we found no reports describing capillary malformations in TBS, we speculate this is unrelated to the other TBS features.
At age 12 months, his length was between À1 and À2 SD, weight for height was below À2.5 SD, and OFC had fallen just below