562 a 22Q11.2 Deletion That Excludes UFD1L and CDC45L in a Patient

562 Letters to the Editor L, Schwartz C, et al. (1997) Determination of the genomic phenotype (Shaikh et al. 1999; Yamagishi et al. 1999). structure of the XNP/ATR-X gene, encoding a potential zinc- However, several of the aforementioned patients (some finger helicase. Genomics 43:149–155 of whom have cardiac and craniofacial defects) have Villard L, Saugier-Veber P, Gecz J, Matteí JF, Munnich A, Lyon- deletions that do not include the region containing these net S, Fonte´s M (1996b) XNP mutation in a large family genes. These observations suggest that additional se- with Juberg-Marsidi syndrome. Nat Genet 12:359–360 quences within the TDR affect early craniofacial and Villard L, Toutain A, Lossi AM, Gecz J, Houdayer C, Moraine C, Fonte´s M (1996c) Splicing mutation in the ATR-X gene cardiac morphogenesis. Additionally, a patient with fea- can lead to a mental retardation phenotype without alpha- tures of DGS and with a microdeletion that falls outside thalassemia. Am J Hum Genet 58:499–505 the TDR but that does not overlap with any of the known deletions was recently described (Rauch et al. Address for correspondence and reprints: Dr. M. Fonte´s, INSERM U491, 1999). This patient had craniofacial abnormalities and Faculte´deMe´decine La Timone, 27 Boulevard J. Moulin 13385 Marseille Cedex 5, France; E-mail: [email protected] an interrupted aortic arch (type B) with truncus arter- *The first two authors contributed equally to this work. iosus, the same defect seen in the patient described by ᭧ 1999 by The American Society of Human Genetics. All rights reserved. Yamagishi et al. (1999). The report by Rauch et al. fur- 0002-9297/99/6502-0033$02.00 ther emphasizes the likelihood that the 22q11.2-related cardiac defects are unlikely to result from defects in- volving a single gene within the TDR. We have identified a patient, CH98-18 (Emanuel et Am. J. Hum. Genet. 65:562–566, 1999 al. 1998), with a novel deletion of chromosome 22q11.2. His deletion is distal to the usual 3-Mb deletion found in most patients with VCFS and appears to overlap with A 22q11.2 Deletion That Excludes UFD1L and a portion of the deleted region described by Rauch et CDC45L in a Patient with Conotruncal and al. (1999). The deletion does not overlap with any Craniofacial Defects of the previously described “minimal critical regions” for VCFS/DGS. The patient was born to a 33-year-old To the Editor: mother at 35 wk gestation. The pregnancy was com- Microdeletions of chromosome 22q11.2 occur with a plicated by a weight gain of 70 lbs and premature rup- high frequency in the general population, with an esti- ture of membranes. The baby was delivered by cesarean mated incidence of 1/3,000–1/4,000 (Burn and Good- section, because of breech presentation, with Apgar ship 1996). They have been shown to be associated with scores of 7 at 1 min and 8 at 5 min. Physical examination the malformation phenotypes of velocardiofacial syn- at birth was notable for an appropriate-for-gestational- drome (VCFS [MIM 192430]), DiGeorge syndrome age infant with hypertelorism, posteriorly rotated ears, (DGS [MIM 188400]), and conotruncal anomaly face micrognathia, a loud cardiac murmur, hypospadias, de- syndrome (CAFS [MIM 217095]) (Emanuel et al. scended testes, single palmar creases, and 5th-finger cli- 1999a). Deletions of this region have also been dem- nodactyly bilaterally. Renal and cranial ultrasounds onstrated in some patients with the autosomal dominant were normal. Echocardiography showed the presence of form of Opitz G/BBB syndrome (MIM 145410) truncus arteriosus type II and a ventricular septal defect. (McDonald-McGinn et al. 1995). Significant phenotypic Borderline hypocalcemia was also present. The patient overlap is found among these entities, including cono- had surgical repair of his truncus arteriosus at age 3 wk truncal cardiac defects, craniofacial anomalies, learning and a replacement graft at age 7 mo. disabilities, and cleft palate. The spectrum of clinical Motor development was normal. The patient sat at findings shows considerable variability, even within fam- age 6 mo and walked at age 14 mo. However, he had ilies (McLean et al. 1993). expressive-speech delay, speaking his first words at age Although the overwhelming majority (185%) of pa- 21 mo. At age 26 mo, he had speech appropriate for an tients have deletions of the same ∼3-Mb region (Emanuel 18-month-old. During a recent physical examination at et al. 1999a), several reports have described patients age 26 mo (fig. 1), short stature, microcephaly, a prom- with atypical, shorter deleted segments nested within the inent glabella, partially attached earlobes, a broad nasal large typically deleted region (TDR) (Levy et al. 1995; bridge, a broad nasal tip with a crease, hypoplastic nasal Kurahashi et al. 1996; O’Donnell et al. 1997; McQuade alae, anteverted nares, a featureless philtrum, a down- et al. 1999). Recently, a small, 20-kb deletion within the turned mouth, a bifid uvula, and normal hearing and TDR was reported in a patient with a classic VCFS/DGS vision were noted. Endocrine evaluation including thy- phenotype. This smaller deletion disrupts the UFD1L roid-function and growth-hormone panels was unre- and CDC45L genes, the products of which (in particular, markable. Immunologic studies including surface mark- UFD1L) have been suggested to play important roles in ers for T-cell, B-cell, and NK lineages, myeloid markers, craniofacial and cardiac development resulting in the leukocyte adhesion, and Wiskott-Aldrich–associated Letters to the Editor 563 Figure 1 Photographs of patient CH98-18 at age 26 mo. Note hypertelorism, broad nose, and micrognathia. proteins were all normal. Proliferative responses to mito- in the mechanism etiologic for the 22q11.2 deletions gen-stimulation tests were also normal, as were function- (Emanuel et al. 1998, 1999b; Edelmann et al. 1999). al-antibody responses. We predicted, on the basis of the presence of additional GTG-banded chromosomes prepared directly from BCRL and GGTL duplicated sequences distal to the peripheral-blood lymphocytes showed a normal 46,XY TDR, that CH98-18’s deletion might involve one of karyotype, and FISH was negative for a deletion when these elements. Thus, the extent of his deletion was inves- the N25 (Oncor) probe was used (fig. 2A). In addition, tigated on the basis of the map of the region immediately CH98-18 did not have a deletion for a number of other distal to the TDR. This region contains the immuno- cosmid-based FISH markers within the TDR, including globulin-l light-chain locus (IGLL), within which are D22S788, ZNF74, HCF2, and cHKAD26 (fig. 2B) located BCRL4 and a copy of GGTL (Kawasaki et al. (Emanuel et al. 1998). With the exception of cHKAD26, 1995). The IGLL locus has been completely character- cosmids used for FISH were isolated by colony hybridized in a cosmid contig (Kawasaki et al. 1995) and has ization from the chromosome 22–specific cosmid library been sequenced (Kawasaki et al. 1997). Using the cosmid (LL22NCO3) generated at the Lawrence Livermore Lab- and sequence reagents, we moved distally from D22S801 oratories. The cosmid that contains the cHKAD26 locus (LN80) into the IGLL to detect the deletion end point was provided by the Japanese Cancer Research Re- (DEP). To insure that the germline genomic configura- sources Bank. A cosmid, 83C5, containing the portions tion of this region was being investigated, all studies of the UFD1L and CDC45L genes deleted in the patient were performed on cultured peripheral-blood lympho- of Yamagishi et al. (Shaikh et al. 1999) was also used cytes. We determined that, although cosmid 61E11 is for FISH and was not deleted (data not shown). We deleted, 102D1 is the first cosmid not deleted in CH98- determined that a cosmid located distally in the TDR 18 (fig. 2A and B). In the sequenced contig, these cos- (107D7) was not deleted (fig. 2B). Because the clinical mids are separated by ∼40 kb that contain BCRL4 and findings in the patient, including truncus arteriosus, a GGTL. Using DNA sequence information for 102D1, bifid uvula, hypoplastic alar nasi, and a history of hy- we designed PCR-based 2.0-kb FISH probes and deter- pocalcemia, were consistent with those seen in VCFS, mined that both ends of this cosmid, which is immedi- additional analysis was undertaken. Use of a series of ately distal to the BCRL4/GGTL duplicated sequence in cosmid and bacterial artificial-chromosome–derived the IGLL locus, are present (GenBank). These probes are probes for FISH demonstrated, initially with a cosmid present, then, on both homologues. Results for one of for locus D22S801, that a deletion adjacent to the TDR these probes are shown in figure 2A. Thus, our patient’s was present (fig. 2A,b and B). Both of CH98-18’s par- telomeric DEP involves a duplicated-sequence block that ents were analyzed by FISH with the cosmid for contains BCRL4 and GGTL sequences. The presence of D22S801 and were found not to have a deletion, indi- a DEP in the vicinity of the BCRL4/GGTL duplication cating a de novo origin of the deletion. suggests unequal crossing-over in the formation of the We and others have implicated blocks of duplicated patient’s deletion. Additional cosmids distal to 102D1 DNA sequence containing BCRL and GGTL elements were examined by FISH, and all were present on both Figure 2 A, Dual-color FISH for DEP positioning in patient CH98-18. All metaphase spreads are hybridized with a control cosmid containing the distal marker D22S39. D22S39 was biotinylated and detected with avidin-FITC to identify chromosome 22 (seen at the telomeric end of chromosome 22, in all panels [green]).

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