Branchiootorenal Syndrome and Oculoauriculovertebral Spectrum
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ß 2008 Wiley-Liss, Inc. American Journal of Medical Genetics Part A 146A:2480–2489 (2008) Branchiootorenal Syndrome and Oculoauriculovertebral Spectrum Features Associated With Duplication of SIX1, SIX6, and OTX2 Resulting From a Complex Chromosomal Rearrangement Zhishuo Ou,1 Donna M. Martin,2,3 Jirair K. Bedoyan,2 M. Lance Cooper,1 A. Craig Chinault,1 Pawel Stankiewicz,1 and Sau W. Cheung1* 1Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 2Department of Pediatrics, University of Michigan Medical School, Ann Arbor, Michigan 3Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan Received 21 December 2007; Accepted 29 April 2008 We report on a 26-month-old boy with developmental delay 13q21.31–q21.32 in both the propositus and his father and and multiple congenital anomalies, including many features FISH supported the apparent association of the two events. suggestive of either branchiootorenal syndrome (BOR) or Chromosome 14q22.3–q23.3 contains 51 genes, including oculoauriculovertebral spectrum (OAVS). Chromosomal SIX1, SIX6, and OTX2. A locus for branchiootic syndrome microarray analysis (CMA) initially revealed a copy-number (BOS) has been mapped to 14q21.3–q24.3, and designated gain with a single BAC clone (RP11-79M1) mapping to as branchiootic syndrome 3 (BOS3). Interestingly, mutations 14q23.1. FISH analysis showed that the third copy of this in SIX1 have been reported in patients with BOR/BOS3. We genomic region was inserted into the long arm of one propose that the increased dosage of SIX1, SIX6,orOTX2 chromosome 13. The same pattern was also seen in the may be responsible for the BOR and OAVS-like features in chromosomes of the father, who has mental retardation, this family. ß 2008 Wiley-Liss, Inc. short stature, hypernasal speech, and minor craniofacial anomalies, including tall forehead, and crowded dentition. Subsequent whole genome oligonucleotide microarray Key words: SIX1; SIX6; OTX2; branchiootorenal syn- analysis revealed an 11.79 Mb duplication of chromosome drome; oculoauriculovertebral spectrum; segmental trisomy; 14q22.3–q23.3 and a loss of an 4.38 Mb sequence in insertional translocation How to cite this article: Ou Z, Martin DM, Bedoyan JK, Cooper ML, Chinault AC, Stankiewicz P, Cheung SW. 2008. Branchiootorenal syndrome and oculoauriculovertebral spectrum features associated with duplication of SIX1, SIX6, and OTX2 resulting from a complex chromosomal rearrangement. Am J Med Genet Part A 146A:2480–2489. INTRODUCTION anomalies, middle ear anomalies, inner ear anoma- lies, preauricular tags, facial asymmetry, and palate Branchiootorenal syndrome (BOR; OMIM 113650) abnormalities, or (3) one major criterion and an is an autosomal dominant disorder caused by affected first-degree relative who meets the criteria mutations in the EYA1 gene (OMIM 601653) [Abdel- for BOR syndrome [Chang et al., 2004]. Branchiootic hak et al., 1997], a human homolog of the Drosophila syndrome (BOS; OMIM 602588), a related disorder eyes absent gene (Eya) [Bonini et al., 1993]. BOR is but without the renal anomalies, can also be caused characterized by hearing loss, branchial cleft fistulas by allelic defects in EYA1 [Vincent et al., 1997]. or cysts, ear pits, renal dysplasia, and otologic A second locus for BOS was localized to chromo- manifestations ranging from mild hypoplasia to complete absence with reduced penetrance and variable expressivity [Melnick et al., 1975; Fraser *Correspondence to: Dr. Sau W. Cheung, Ph.D, M.B.A, Department of et al., 1978]. Clinical diagnosis of BOR is based on the Molecular and Human Genetics, Baylor College of Medicine, John P. presence of (1) at least three major criteria including McGovern Campus, Rm. NABS-270, Houston, TX 77030. branchial anomalies, deafness, preauricular pits, and E-mail: [email protected] Published online 29 July 2008 in Wiley InterScience renal abnormalities, (2) two major criteria, and at (www.interscience.wiley.com) least two minor criteria including external ear DOI 10.1002/ajmg.a.32398 American Journal of Medical Genetics Part A SIX1 DUPLICATION ASSOCIATED WITH BOR AND OAVS 2481 some 1q31 (OMIM 120502) [Kumar et al., 2000]. and two other paternal relatives have the same Recently, Ruf et al. [2003] mapped a third gene locus unbalanced aberration and learning disability, sig- for BOR/BOS to 14q21.3–q24.3 by linkage study and nificant developmental delays, and subtle dysmor- designated it as branchiootic syndrome 3 (BOS3; phic features. We propose that increased dosage of OMIM 608389). This chromosomal region contains SIX1, SIX6,orOTX2 may be responsible for BOR- the SIX1, SIX4, SIX6 (OMIM 601205, OMIM 606342, and OAVS-like phenotypes in this family. OMIM 606326, respectively) gene cluster, the prod- ucts of which are known to act in a developmental CLINICAL REPORT pathway of the EYA genes [Xu et al., 1999], and OTX2 (OMIM 600037). Mutations in SIX1 have been The propositus (Fig. 1A–C) is a 26-month-old male reported in patients with BOR/BOS, thus identifying born to a primiparous 21-year-old woman at SIX1 as a gene causing BOR and BOS [Ruf et al., 39 weeks by cesarean section. Ultrasound studies at 2004]. 21 weeks gestation suggested an occipital encepha- Oculoauriculovertebral spectrum (OAVS; OMIM locele or meningocele. Amniocentesis performed at 164210) is a common birth defect pattern (1 in 5,600 11 weeks showed a normal male karyotype. His birth live births) involving first and second branchial arch weight was 1,997 g (1st centile) and head circum- derivatives [Gorlin et al., 1990, 2001]. The phenotype ference was 31 cm (2nd centile). Initial evaluation of OAVS is extremely variable, with no generally at 6 weeks of age indicated a weight of 3.04 kg accepted minimal diagnostic criteria [Regenbogen (<3rd centile), length of 48.1 cm (<3rd centile) and et al., 1982; Kaye et al., 1992]. The disorder includes head circumference of 34.7 cm (1st centile). At the Goldenhar syndrome, which is defined as the 8 months weight was 5.49 kg (<3rd centile), length combination of microtia, hemifacial microsomia, 61.7 cm (<3rd centile) and head circumference dermoids, and vertebral anomalies. The features of 41.1 cm (<3rd centile); he could smile and babble, OAVS include unilateral malformation of the external reach for objects, and transfer objects from hand to ear and asymmetric facial hypoplasia with epibulbar hand. He was turning to voices, but was not yet dermoid and vertebral anomalies. Coloboma of the sitting. Re-evaluation at 26 months showed persistent upper eyelid is frequent. The ear defects include growth delays and microcephaly, with weight preauricular tags of cartilagenous masses, atresia of 7.65 kg (<3rd centile), length 76.3 cm (<3rd centile) the external auditory canal, anomalies in the size and and head circumference 43.5 cm (<3rd centile). He shape of the external auricle, and anotia [Gorlin et al., was walking with some assistance and using several 2001]. Cardiac, vertebral, and central nervous system single words to communicate. defects have also been described [Rollnick et al., Physical findings first noted in the newborn period 1987]. The etiology of OAVS is unclear; autosomal included large fontanels and a tall prominent fore- dominant, autosomal recessive and multifactorial head. The right occiput appeared more prominent inheritance have been described [Rollnick and Kaye, than the left occiput. Torticollis to the left was noted. 1983; Kelberman et al., 2001]. Chromosomal abnor- He had a recessed jaw with a highly arched palate malities described in patients with OAVS include and possible short tongue. He had multiple skin trisomies 18 [Verloes et al., 1991] and 22 [Kobrynski tags in the preauricular and cheek regions as well as et al., 1993], mosaic trisomies 9 [Wilson and Barr, pits on the right cheek. Other dysmorphic features 1983] and 17 [Hodes et al., 1981], duplication of 8pter included short nose with broad nasal bridge, short [Josifova et al., 2004], deletions of 5p14 to 5pter palpebral fissures with copious tearing suggesting [Choong et al., 2003] and 22qter [Herman et al., 1988], lacrimal duct stenosis (he underwent subsequent pericentric inversions of chromosome 1 with break- lacrimal duct stent placement bilaterally), low set points at p13 and q21 [Stahl-Mauge´ et al., 1982] and ears with abnormal antihelix and ear lobe, prom- chromosome 9 with breakpoints at p11 and q13 inence of the maxilla, severe hypoplasia of the [Stanojevic´ et al., 2000], and the recurrent unbalanced mandible with broadening of the oral region, and translocation der(11)t(11;22)(q23;q112) [Balci et al., macrostomia with bilateral Tessier number 7 clefts 2006]. Furthermore, data from a family with features (with subsequent surgical reconstruction at 8 months of hemifacial microsomia suggest linkage to a region of age) and micrognathia. His neck appeared short of approximately 10.7 cM on chromosome 14q32 and abnormally shaped but with no webbing. [Kelberman et al., 2001]. Cranial ultrasound showed normal sulcal pattern We describe a patient with features of BOR and with no ventriculomegaly. MRI of the brain on day of OAVS in whom a chromosome segment from life 4 showed no evidence of hydrocephalus or Chiari 14q22.3–q23.3 is duplicated and directly inserted malformation. A 5 cm meningocele was noted with into chromosome 13q21, resulting in a 11.79 Mb fibrous band tissue and dura but no brain paren- trisomy of chromosome 14q22.3–23.3 that includes chyma. Corpus callosum was thin. SIX1, SIX6, OTX2, and an associated deletion of an Because of a deep sacral dimple, neonatal ultra- 4.38 Mb gene-poor region on chromosome sound of the spinal cord was performed and showed 13q21.31–q21.32. Interestingly, the patient’s father conus tip slightly low at L4 with normal filum American Journal of Medical Genetics Part A 2482 OU ET AL. FIG.1. Photographs of the propositus 26 months (A–C) and his father (D–F).