Supernumerary Marker Chromosome 15 in a Male with Azoospermia and Open Bite Deformity
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Asian Journal of Andrology (2009) 11: 617–622 npg © 2009 AJA, SIMM & SJTU All rights reserved 1008-682X/09 $ 32.00 617 www.nature.com/aja Original Article Supernumerary marker chromosome 15 in a male with azoospermia and open bite deformity Altuğ Koç1, S. Ödül Onur2, Mehmet Ali Ergün1, E. Ferda Perçin1 1Department of Medical Genetics, Gazi University, Faculy of Medicine, Ankara 06500, Turkey 2Private Practice, Tunali Hilmi Cad. 70/18 06680 Kavaklidere Ankara 06680, Turkey Abstract Supernumerary marker chromosome 15 (sSMC[15]) is the most frequent marker chromosome, and it is generally regarded as unimportant if it does not contain the Prader–Willi/Angelman syndrome critical region (PWACR). The clinical importance of the larger markers in association with the critical region is mentioned in almost all reports related to marker chromosome 15, and smaller markers are solely associated with minor dysmorphic features, azoospermia and recurrent miscarriages. However, these small sSMC(15)s without the PWACR may also determine a specific phenotype. A dysmorphic examination of an azoospermic patient in a genetics clinic was performed and was followed by a peripheral blood lymphocyte chromosomal analysis according to standard cytogenetic methods. Nucleolar region (NOR) banding, C-banding, fluorescence in situ hybridization and a molecular investigation of Y-microdeletions were also performed. The clinical evaluation identified dysmorphic features accompanied with azoospermia and severe ‘Angle Class II, Division 1 Open Bite Deformity’. The molecular cytogenetic study revealed the small sSMC(15). In addition, a Y-microdeletion analysis showed that the azoospermia was not the result of a deletion. Although the presented case might represent a coincidental example of supernumerary marker 15 and mandibular anomaly association, the condition may also define a specific phenotype that may be more than azoospermia. This condition may be characterized by infertility, malar hypoplasia, mandibular anomaly, keloid formation and minor dysmorphic features. Asian Journal of Andrology (2009) 11: 617–622. doi: 10.1038/aja.2009.37; published online 24 August 2009. Keywords: auriculocondylar syndrome, azoospermia, infertility, isodicentric 15q, open bite deformity, small supernumerary marker chromosome 15 1 Introduction humans [1–5]. The most common supernumerary marker chromosome (sSMC) in humans is sSMC(15), Marker chromosomes are frequently supernumerary and it accounts for as much as 50%–60% of all sSMCs and occur at a frequency of about 0.3–0.5/1 000 in observed [3, 5, 6]. In addition, sSMC(15)s occur predominantly as small pseudodicentric chromosomes that are termed psu dic(15; 15) or inv dup(15) [7, 8]. Carriers of sSMC(15) without euchromatin were Correspondence to: Associate Professor Mehmet Ali Ergün, De- found to be normal, but this kind of sSMC(15) has been partment of Medical Genetics, Gazi University Faculty of Medi- detected with a high incidence among infertile males cine, Ankara 06500, Turkey. Fax: +90-312-2024-635 E-mail: [email protected] [5, 7, 9, 10]. It is currently thought that spermatogenic Received: 16 December 2008 Revised: 22 April 2009 impairment due to the presence of sSMCs is the cause Accepted: 21 May 2009 Published online: 24 August 2009 of oligospermia [11]. In familial cases, females usually http://www.asiaandro.com; [email protected] | Asian Journal of Andrology npg sSMC (15) with azoospermia and open bite Altuğ Koç et al. 618 present with normal fertility, but maternal transmission attached ear lobes, a right-sided simian crease and a of sSMC(15) may lead to infertile male offspring [9]. keloid scar on the left palm (Figure 1A, B). The presence of the Prader–Willi/Angelman syn- The orthodontic history of the patient began drome critical region (PWACR) on sSMC(15) is with the chief complaint of the supernumerary tooth the main determinant of the sSMC(15) phenotype. beyond the incisors and speech problems related with PWACRs containing sSMC(15), which are large his dentition. A long face and convex soft tissue sSMCs, cause highly variable clinical phenotypes profile were also noted (Figure 2A–E). The clinical that are dependent on the location of breakpoints, the oral and dental examination revealed that he was in copy number of the PWACR region and the ratio of the permanent dentition stage, with the exception of mosaicism; the clinical picture frequently includes the upper left central deciduous incisor. There was a hypotonia, motor and speech delay, seizures, moderate supernumerary tooth beyond the right central incisor. to severe learning disability, autism and Prader–Willi/ The anterior occlusion showed a severe open bite, Angelman syndromes [1, 4, 7, 8, 12–18]. It is generally and there were generalized and severe hypoplasias on considered that patients with small sSMC(15)s, which the upper and lower incisors and canines. In addition, do not contain PWACRs, have no clinical symptoms [8]. polydiastemas were observed in both arches because of Small sSMC(15)s may arise during spermatogenesis the small teeth, according to the dental arches. [1, 19]. Individuals with sSMC(15) also seem to be at increased risk for uniparental disomy of the two normal 2.2 Methods copies of chromosome 15, which results in the Prader– Willi or Angelman syndromes [9]. 2.2.1 Radiological investigation In this report, we present an azoospermic man with After the identification of azoospermia, an evaluation small sSMC(15) and having distinguishing dysmorphic of the patient’s urogenital system by ultrasonography features. We have attempted to define the possible was performed. phenotype of this relatively common marker genotype. 2.2.2 Pathological examination 2 Materials and methods A testicular biopsy was performed. Radiological examination of the oral region and a cephalometric 2.1 Subject analysis were also performed. One azoospermic male with dysmorphic features and his healthy parents were studied. 2.2.3 Cytogenetic study Karyotyping of peripheral blood lymphocytes from 2.1.1 Case history the patient and his parents was performed through An 18-year-old Turkish male was referred for gene Giemsa–Trypsin (GTG) banding. C-banding and tic evaluation because of azoospermia. He was born nucleolar region (NOR) banding were also used for at term to a 38-year-old, gravida 7, para 7 woman after the investigation of constitutive heterochromatin and an uncomplicated delivery. The postnatal history was satellite DNA, respectively. unremarkable except for bilateral cryptorchidism, and the developmental milestones during childhood 2.2.4 Molecular cytogenetic studies were reached appropriately. The parents were not Fluorescence in situ hybridization was used for the consanguineous, and the family history of the patient investigation of the origin of the marker chromosome, was not important except for the sudden death of two and the technique was performed using the commercial brothers in the neonatal period. In his medical history, Prader–Willi/Angelman (SNRPN) Region Probe with our patient had orchiopexy and orthodontic operations cep 15 as a control probe (Cytocell, Cambridge, USA). at 16 years of age. At his physical examination, he was 176 cm tall 2.2.5 Molecular study (50–75th percentile), 64 kg (25–50th percentile) and his A Y-microdeletion study was performed using a head circumference was recorded as 56 cm (10–25th commercial kit (Promega, Madison, WI, USA) for percentile). He had articulation problems, a triangular azoospermia factor region (AZFa, AZFb, AZFc)- face, synophris, a high arched palate, hypoplastic teeth, specific primers. Asian Journal of Andrology | http://www.asiaandro.com; [email protected] sSMC (15) with azoospermia and open bite Altuğ Koç et al. npg 619 Figure 1. Images of the patient after orthodontic surgery. (A): Anterior view of the patient showing: triangular face, synophris, prominent nose, scant facial hair and attached ear lobes. (B) Lateral view of the patient. Figure 2. Images of the oral region before orthodontic surgery. (A–E): Extraoral and intraoral photographs of the patient. (F–H): Lateral, anteroposterior, and panoramic radiographs of the patient. 3 Results normal anatomical structures. An examination of the oral region showed that two 3.1 Radiological investigation supernumerary teeth existed between the right and left Ultrasonography of the urogenital system revealed incisors. The left supernumerary tooth was blocking http://www.asiaandro.com; [email protected] | Asian Journal of Andrology npg sSMC (15) with azoospermia and open bite Altuğ Koç et al. 620 the eruption path of the left central incisor, which dysmorphic features. was impacted (Figure 2F–H). Cephalometric analysis revealed a severe dolichofacial class II skeletal pattern 3.4 Molecular cytogenetic study with an anterior open bite owing to the micrognathic In the FISH study, all of the interphase and and retrusive mandible relative to the anterior cranial metaphase cells had three signals specific to the base and maxilla (Figure 2F–H). centromere of chromosome 15 owing to sSMC(15) (Figure 3). Commercial probes specific for SNRPN 3.2 Pathological examination 15qter regions (Cytocell, USA) showed the absence of Testes dimensions for the right and left testicles were signals on the sSMC. 30 × 26 × 10 mm and 15 × 12 × 8 mm, respectively. The following testicular biopsy showed Sertoli-cell-only 3.5 Molecular study syndrome. The molecular study for microdeletions of azoospermia factors on the Y chromosome exhibited an 3.3 Cytogenetic studies intact constitution. Karyotyping of the patient revealed 47, XY, + mar by GTG banding. C-banding and NOR banding identified 4 Discussion the bisatellited isodicentric nature of the marker chromosome. Karyotyping of the father and the mother Although the sSMC(15) is the most common of the patient determined the parental origin of the marker chromosome in humans, a clear description of supernumerary marker; the mother was also established the phenotype of patients is restricted. The difficulty is to be the carrier for sSMC(15). The mother had no mainly a result of the variability of breakpoints; thus, Figure 3.