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CASE REPORT J Clin Pathol: first published as 10.1136/jcp.2004.017475 on 27 August 2004. Downloaded from A case of 49,XXXXX in which the extra X chromosomes were maternal in origin Y G Cho, D S Kim, H S Lee, S C Cho, S I Choi ......

J Clin Pathol 2004;57:1004–1006. doi: 10.1136/jcp.2004.017475

the manufacturer’s instructions. Data were processed by This report describes an 11 month old female baby with GeneScanTM and GenotyperTM software (Applied Biosystems). features of pentasomy X. A molecular and cytogenetic The most typical features of this infant were muscular evaluation revealed that her was 49,XXXXX and , mental retardation, and mild hydrocephalus as her extra X chromosomes were of maternal origin. She has a result of dilatation of both lateral ventricles. A magnetic muscular hypotonia, mental retardation, a cleft palate, mild resonance imaging scan of the brain was done to hydrocephalus as a result of dilatation of both lateral investigate the brain abnormalities, and showed dilatation ventricles, hyperextensible elbow joints, proximal radioulnar of both lateral ventricles combined with mild leucomalacia synostosis, of the fifth finger, valgus of the feet, in the periventricular area. and small hands and feet. In addition, she has a persistent The general appearance of the patient showed the typical pupillary membrane and congenital chorioretinal atrophy. dysmorphism of pentasomy X (fig 2). Characteristic cranio- The pathogenesis of pentasomy X is not clear at present, but it facial features, such as , a flat broad nose, cleft is thought to be caused by successive maternal non- palate, a persistent pupillary membrane, congenital chorio- dysjunctions. retinal atrophy, micrognathia, and malformed teeth, were found. She had a hyperextensible joint at the elbows, proximal radioulnar synostosis in the right forearm, clino- dactyly of the fifth finger, small hands and feet, and valgus entasomy X is a rare chromosomal abnormality that of the feet. A laboratory evaluation revealed a normal affects girls only, and is characterised by the presence of leucocyte count and a normal differential blood count. IgA five X chromosomes instead of two. The first case of this (392 mg/litre), IgM (1280 mg/litre), and IgG2 (960 mg/litre) P 1 chromosomal abnormality was reported in 1963. The were low, although total IgG was normal (8720 mg/litre). condition is typically characterised by severe mental retarda- There was no history of an increased incidence of recurrent tion, craniofacial malformation, , and other infections. physical abnormalities. The true incidence of pentasomy X is unknown at present, and the only known risk factor is female DISCUSSION sex. We present a case of pentasomy X with maternal origin Pentasomy X has several synonyms, namely: penta-X http://jcp.bmj.com/ of the extra X chromosomes. syndrome, chromosome X pentasomy, poly-X, and XXXXX syndrome. Numerical abnormalities of the sex chromosomes ‘‘The true incidence of pentasomy X is unknown at present, such as 47,XXX, 47,XXY, 47,XYY, and 45,X are relatively common, and occur in approximately 1 of 400 live births,2 but and the only known risk factor is female sex’’ to our knowledge only about 30 cases of pentasomy X have been reported previously. This aneuploid state must arise as a result of a meiotic malfunction, either maternal or combined on October 4, 2021 by guest. Protected copyright. CASE REPORT maternal and paternal in origin. The most likely mechanism The patient was an 11 month old girl, the second child of is non-dysjunction of the maternal X chromosomes in both healthy unrelated parents (mother aged 29, father 33). She divisions of meiosis to produce an XXXX ovum, and this was born by caesarean section during the 36th gestational hypothesis has been supported by molecular analysis of X week as a result of premature membrane rupture. Her birth linked polymorphic markers.3 The microsatellite analysis weight was 2400 g (20–50th centile), length was 45.4 cm used in our study showed that the extra X chromosomes (25th centile), and head circumference was 34 cm (75–90th seen in our patient were maternal in origin, probably as a centile). Her sibling was healthy and normally developed. result of successive maternal non-dysjunctions. Cytogenetic analysis was requested on the third day after The parents of the patient were healthy and unrelated. The birth because the infant had a cleft palate with ventriculo- mother was 29 years old and the father was 33 years at the megaly, and was performed on the patient’s cultured time of her birth, figures that are similar to previous peripheral blood lymphocytes. All of the 20 cells analysed reports.45 The age of the mother is one of the contributing had an abnormal karyotype of 49,XXXXX (fig 1A). Both the factors in Down’s syndrome, but the influence of the parents and her sibling have a normal karyotype. mother’s age on the occurrence of penta-X syndrome has A molecular study using microsatellite markers (ABI not been determined. PrismH linkage mapping set v2.5; Applied Biosystems, Because most patients with penta-X syndrome (including Foster City, California, USA) located on the ours) have hypertelorism, epicanthus, and a mongoloid slant revealed that the peak area ratio of the mother and father in of palpebral fissures as facial anomalies, similar to the the patient’s informative markers was 3.99–4.59 to 1, abnormalities seen in Down’s syndrome, occasional diag- indicating that her extra X chromosomes were maternal in nostic problems have been reported.5 Thus, patients can be origin (fig 1B). All analyses were performed on a 3100 ABI misdiagnosed as having Down’s syndrome, so that the correct Prism genetic analyserTM (Applied Biosystems), according to diagnosis requires cytogenetic analysis.

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Figure 1 The results of a molecular and cytogenetic study in our case. (A) J Clin Pathol: first published as 10.1136/jcp.2004.017475 on 27 August 2004. Downloaded from The karyotype of our patient showing 49,XXXXX (G banding; original magnification, 61000). (B) Marker map, red arrows indicate informative markers and blue arrows non- informative markers. (C) The results of microsatellite analysis. The peaks of three informative X linked markers (DXS1001, DXS1047, and DXS8019) seen in the extra X chromosomes of our case are the same as those of her mother. http://jcp.bmj.com/

The clinical manifestations seen in our case were consistent craniofacial anomalies, skeletal abnormalities, and cardio- with those described previously in patients with pentasomy vascular anomalies. At first glance, our patient appeared to be X.1 3–7 They included mental and developmental retardation, normal, but she had multiple malformations and abnormal laboratory findings. The common features found in pre- on October 4, 2021 by guest. Protected copyright. viously described patients and our patient were mental retardation, hypertelorism, mongoloid slant of palpebral fissures, a flat broad nose, malformed teeth, normal external genitalia, clinodactyly of the fifth finger, small hands and feet, and congenital heart disease. In contrast, features found frequently in previous patients and not in our patient included a short neck, a simian crease, and overlapping toes. A persistent pupillary membrane and congenital chorioretinal atrophy were unique to our patient. In addition, most of the other patients had varus of the feet, whereas our patient had valgus.

‘‘Patients can be misdiagnosed as having Down’s syndrome, so that the correct diagnosis requires cyto- genetic analysis’’

The normal external genitalia seen in our patient have been reported in previous patients examined,14 although gonadal Figure 2 (A) Photograph showing the facial appearance of the patient 11 months after birth. Characteristic facial features such as dysfunction has been seen in many cases, including a 467 hypertelorism, a flat broad nose, and micrognathia are well portrayed. postmortem case. These findings suggest that despite (B) Cleft in the soft palate of our patient. the normal appearance of the external genitalia, there is an

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psychomotor development from early infancy, as seen in our

Take home messages patient, has also been described in this syndrome. J Clin Pathol: first published as 10.1136/jcp.2004.017475 on 27 August 2004. Downloaded from

N We describe an 11 month old girl with features of ...... pentasomy X: muscular hypotonia, mental retardation, Authors’ affiliations a cleft palate, mild hydrocephalus as a result of Y G Cho, D S Kim, H S Lee, Department of Laboratory Medicine, Chonbuk National University Medical School, Chonbuk National dilatation of both lateral ventricles, hyperextensible University, 634-18 Keumam-dong, Dukjin-ku, Jeonju 561-712, Korea elbow joints, proximal radioulnar synostosis, clinodac- S C Cho, Department of Paediatrics, Chonbuk National University tyly of the fifth finger, valgus of the feet, and small Medical School hands and feet S I Choi, Department of Laboratory Medicine, Chonbuk National N She also has a persistent pupillary membrane and University Medical School and Research Institute of Clinical Medicine, congenital chorioretinal atrophy Chonbuk National University N Molecular and cytogenetic evaluation revealed that her Correspondence to: Dr S I Choi, Department of Laboratory Medicine, karyotype was 49,XXXXX and her extra X chromo- Chonbuk National University Medical School and Research Institute of somes were of maternal origin Clinical Medicine, Chonbuk National University, 634-18 Keumam- N Pentasomy X may be caused by successive maternal dong, Dukjin-ku, Jeonju 561-712, Korea; [email protected] non-dysjunctions Accepted for publication 2 March 2004

REFERENCES underlying gonadal dysfunction in patients with penta-X 1 Kesaree N, Woolley PV. A phenotypic female with 49 chromosome, syndrome. Because our patient was an infant, her sexual presumable XXXXX. J Pediatr 1963;63:1099–103. development and bone maturation remain to be assessed. 2 Alan S, Issac S, Dinesh KP, et al. An adult with 49,XYYYY karyotype: case Immunoglobulin values in our case were similar to those report and endocrine studies. Am J Med Genet 1998;80:103–6. 3 3 Boeck A, Gfatter R, Braun F, et al. Pentasomy X and hyper IgE syndrome: co- reported previously in a 49,XXXXX female patient, including existence of two distinct genetic disorders. Eur J Pediatr 1999;158:723–6. reduced serum IgA and IgG2 and normal total IgG. Our 4 Sergovich F, Uilenberg C, Pozsonyi J. The 49,XXXXX chromosome patient’s serum IgA and IgM values were inappropriately low constitution: similarities to the 49,XXXXY condition. J Pediatr compared with age related normal values. However, no 1971;78:285–90. 5 Zhang R, Pan N, Li X, et al. A case of 49,XXXXX syndrome. Chin Med J (Engl) history of a greatly increased incidence of recurrent infections 1982;95:891–4. was found in our patient, whereas Boeck et al described their 6 Toussi T, Halal F, Lesage R, et al. Renal hypodysplasia and unilateral ovarian patient as having a lifelong history of eczema, recurrent agenesis in the penta-X syndrome. Am J Med Genet 1980;6:153–62. pneumonia, and staphylococcal abscess.3 7 Farge P, Dallaire L, Albert G, et al. Oral and dental development in X chromosome . Clin Genet 1985;27:122–6. According to a review of pentasomy X, mental retardation 8 Kassai R, Hamada I, Furuta H, et al. Penta X syndrome: a case report with was seen in all of the 22 cases reported previously.8 Delayed review of the literature. Am J Med Genet 1991;40:51–6. http://jcp.bmj.com/ on October 4, 2021 by guest. Protected copyright.

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