Linkage analysis in a family with the Opitz GBBB syndrome refines the location of the gene in Xp22 to a 4 cM region.

The Opitz GBBB syndrome (OS) is characterized in part by widely spaced inner ocular canthi and hypospadias. Recently, linkage analysis showed that the gene for the X-linked form to be located in an 18 cM region spanning Xp22. We have now conducted linkage analysis in a family previously published as having the BBB syndrome and found tight linkage to DXS7104 (Z=3.3, τ=0.0). Our data narrows the candidate region to 4 cM and should facilitate the identification and characterization of one of the genes involved in midline development.     

一例45,XX,-13/46,XX,r(13)/46,XX,r(13;13)/47,XX,2r(13)(p13q32.3)患者及其表型定位研究

目的　通过对 1例 13号环状染色体综合征患者的染色体分析、表型定位研究和相关文献复习比较 ,探索染色体区带与表型的关系。方法　应用染色体G带、C带、N带、高分辨显带技术、表型定位和文献复习比较分析方法 ,对 1例 13号环状染色体综合征患者进行了研究。结果　患儿双亲核型正常 ,患儿核型为 45 ,XX ,-13 /4 6,XX ,r( 13 ) /4 6,XX ,r( 13 ;13 ) /4 7,XX ,2r( 13 ) ( p13q3 2 .3 ) ;典型的 13号环状染色体综合征与 13q3 4的缺失相关 ;13号环状染色体综合征患者的手足、肾脏、骨骼、外生殖器异常及心脏杂音与 13 q3 2 q3 2 .2片段的缺失有关 ,缩颌与 13q3 2 .3 q3 3片段的缺失相关 ,肛门闭锁与 13 q2 2 q3 2的缺失相关 ,无脑畸形与 13 q13 q2 2片段的缺失相关。 结论　新的环状染色体断裂重接点在 13 p13和 13q3 2 .3 ;13号环状染色体综合征患者临床特征的差异与染色体区带缺失部位的不同密切相关。     

Disruption of genes in the retinoid cascade may explain the microscopic neuroblastoma in a fetus with de novo unbalanced translocation (3;10)(q21;q26)

BBB syndrome and G syndrome were originally reported as distinct X-linked disorders. Clinical studies indicated that BBB and G syndromes were likely to represent variant expression of the same disorder, now referred to as “Optiz” GBBB syndrome. Several occurrences of male-to-male transmission in both syndromes led to the hypothesis that GBBB syndrome was a single autosomal dominant, sec influenced disorder, now tentatively mapped to 5p12-13. We report on a large pedigree in which GBBB syndrome appears to cosegregate with a pericentric inversion of the X chromosome inv(X)(p22.3q26). It indicates the possible existence of a true X-linked form of GBBB syndrome, which does not appear phenotypically different from its autosomal counterpart. The gene could map in the vicinity of the breakpoints, in Xp or Xq. The existence of two genes affecting a common pathogenetic pathway could explain the gender-dependent expressivity of GBBB phenotype. © 1995 Wiley-Liss, Inc.     

A patient with 22q11.2 deletion and Opitz syndrome-like phenotype has the same deletion as velocardiofacial patients

Five patients were previously described with the Opitz (GBBB) syndrome (OMIM 145410) phenotype and 22q11.2 deletion determined by FISH but the precise limits of their deletions have not been determined. Since one locus for Opitz syndrome maps to 22q11.2 and chromosomal arrangements are frequently complex and could inactivate such a locus, we performed high-resolution array-based comparative genomic hybridization (CGH) on a new Opitz syndrome-like phenotype patient with a 22q11.2 deletion. He shares the same deletion as patients with velocardiofacial and DiGeorge syndrome.     

Chromosome 22q11.2 deletion in a boy with Opitz (G/BBB) syndrome

This report is on a 14-month-old boy with manifestations of Opitz (G/BBB) syndrome in whom a 22q11.2 deletion was found. Deletion analysis was requested because of some findings in this patient reminiscent of velocardiofacial (VCF) syndrome. The extent of aspiration and of respiratory symptoms in this child is not usually seen in VCF syndrome. Opitz syndrome maps to at least two loci, one on Xp, the other on 22q11.2. © 1996 Wiley-Liss, Inc.     

Delineation of 14q32.3 deletion syndrome.

A patient with a 14q32.3 terminal band deletion and cat cry is reported. Review of four other 14q32.3 deletion cases suggests the possible presence of a recognisable 14q32.3 terminal deletion syndrome, which is characterised by (1) apparently postnatal onset of small head size in comparison to body size, (2) high forehead with lateral hypertrichosis, (3) epicanthic folds, (4) broad nasal bridge, (5) high arched palate, (6) single palmar crease, and (7) mild to moderate developmental delay. Although none of the above seven features in unique to this syndrome, and indeed are quite common in other chromosomal disorders or genetic syndromes, patients with a terminal 14q32.3 deletion do show a recognisable facial gestalt. Interestingly, unlike ring chromosome 14, the 14q32.3 terminal deletion has rarely been reported, possibly because it is harder to detect, and an optimal chromosome preparation is required for its identification.     

Books received

An infant girl with manifestations resembling Opitz trigonocephaly (C) syndrome who died at age 6 days was found to have a complex chromosome abnormality with t(13;18)(q22;q23) and a recombinant chromosome 13 involving duplicated segments of 13q. Precise characterization was possible with the application of fluorescence in situ hybridization (FISH) using chromosome specific probes. The patient's phenotype is compared to that of other syndromes involving trigonocephaly. © 1994 Wiley-Liss, Inc.     

A case of Costello with parathyroid adenoma and hyperprolactinemia

The clinical phenotype of patients with ring chromosome 22 includes mental retardation with severe language impairment, hypotonia, and dysmorphic facial features. In recent years an increasing number of patients with microscopic as well as cryptic terminal deletion involving band 22q13 have been described and their phenotype shows clinical features overlapping with patients with ring chromosome 22. Loss of DNA in the 22q13.3 region may lead to a clinically recognizable syndrome named "22q13.3 deletion syndrome." We report a patient with a ring chromosome 22 who has hypotonia, profound mental retardation, language impairment, dysmorphic features, and behavioral disorders. To check if the critical region responsible for "22q13.3 deletion syndrome" was absent in this ring, a fluorescent in situ hybridization (FISH) analysis using a probe corresponding to the ARSA locus was performed. In our patient, only one ARSA signal could be detected, indicating that the deletion encompassed the critical 22q13.3 region. A more detailed analysis of the deletion extent then was performed using a panel of fluorescent probes located within 22q13. These experiments allowed the identification of the breakpoint between CTA-299D3 and RP5-925J7 probe, located in 22q13.32. Deletion extent could be estimated to be about 2.5 Mb, and this larger deletion may explain the severity of clinical features observed in our patient.     

Opitz G/BBB syndrome: Clinical comparisons of families linked to Xp22 and 22Q and a review of the literature

Opitz G/BBB syndrome (OS) was first described in 1969 as two separate disorders, the G syndrome, and the BBB syndrome. Since the time, it has become apparent that the BBB and the G syndromes are in fact a single entity, now named the Opitz G/BBB syndrome. However, our recent molecular genetic mapping studies have shown that OS is an heterogeneous disorder, with loci at Xp22 and 22q. To determine if there are any discernible phenotypic differences between the X-linked and the autosomal dominant forms of OS, we have conducted a clinical study of the families who participated in the linkage analysis. In addition, we compared the clinical findings in the study families with those who have been reported in the literature. We found that anterveted nares and posterior pharyngeal cleft were seen only in X-linked families. However, all other manifestations of OS, such as hypertelorism, swallowing difficulties, hypospadias, and developmental delay, were seen in both groups. Therefore, while OS is heterogenous, significant clinical overlap is present between the two groups, and it is presently impossible to assign a specific phenotype to the X-linked or the autosomal type of OS. Furthermore, we found that for individuals in our study families who carried the OS allele, the incidence of major abnormalities was lower than what is reported in the literature. © 1996 Wiley-Liss, Inc.     

Supernumerary inv dup(15) in a patient with Angelman syndrome and a deletion of 15q11–q13

We have studied a patient with Angelman syndrome (AS) and a 47,XY,+inv dup(15) (pter→q11::q11→pter) karyotype. Molecular cytogenetic studies demonstrated that one of the apparently normal 15s was deleted at loci D15S9, GABRB3, and D15S12. There were no additional copies of these loci on the inv dup (15). The inv dup (15) contained only the pericentromeric sequence D15Z1. Quantitative DNA analysis confirmed these findings and documented a standard large deletion of sequences from 15q11-q13, as usually seen in patients with AS. DNA methylation testing at D15S63 showed a deletion of the maternally derived chromosome. AS in this patient can be explained by the absence of DNA sequences from chromosome 15q11-q13 on one of the apparently cytogenetically normal 15s, and not by the presence of an inv dup (15). This is the fourth patient with an inv dup (15) and AS or Prader Willi syndrome, who has been studied at the molecular level. In all cases an additional alteration of chromosome 15 was identified, which was hypothesized to be the cause of the disease. Patients with inv dup (15)s may be at increased risk for other chromosome abnormalities involving 15q11-q13. © 1995 Wiley-Liss, Inc.     

A new X-linked syndrome with agenesis of the corpus callosum, mental retardation, coloboma, micrognathia, and a mutation in the Alpha 4 gene at Xq13

We describe two brothers with a unique pattern of malformations that includes coloboma (iris, optic nerve), high forehead, severe retrognathia, mental retardation, and agenesis of the corpus callosum (ACC). Both boys have low-set cupped ears with sensorineural hearing loss, normal phallus, pectus excavatum, scoliosis, and short stature. One brother had choanal atresia and cardiac defects consisting of ventricular septal defect (VSD) and patent ductus arteriosus (PDA) which resolved spontaneously. Differential diagnosis between a number of clinical entities was considered, however, because ACC and the distinctive facial features were reminiscent of FG syndrome, DNA was analyzed for markers linked to the FGS1 locus at Xq13-q21. Notably, the brothers were concordant for markers spanning this presumed FG region, and in both we have identified adjacent alterations (-57delT and T-55A) in the Alpha 4 gene located within this interval. Alpha 4 is a regulatory subunit of the major cellular phosphatase, PP2A, that has recently been shown to interact with MID1, the product of the gene mutated in X-linked Opitz GBBB syndrome. The double nucleotide change identified in this family was not observed in 410 control chromosomes, suggesting that it may be a pathogenetic change. Altered expression of Alpha 4, through either a change in translational efficiency, mRNA stability or splicing, could explain the clinical phenotype in these boys and the phenotypic overlap with Opitz GBBB syndrome.     

A phenotype map for 14q32.3 terminal deletions

Detailed molecular-cytogenetic studies combined with thorough clinical characterization are needed to establish genotype-phenotype correlations for specific chromosome deletion syndromes. Although many patients with subtelomeric deletions have been reported, the phenotype maps for many of the corresponding syndromes, including the terminal deletion 14q syndrome, are only slowly emerging. Here, we report on five patients with terminal partial monosomy of 14q32.3 and characteristic features of terminal deletion 14q syndrome. Four of the patients carry de novo terminal deletions of 14q, three of which have not yet been reported. One patient carries an unbalanced translocation der(14)t(9;14)(q34.3;q32.3). Minimum deletion sizes as determined by molecular karyotyping and FISH are 5.82, 5.56, 4.17, 3.54, and 3.29?Mb, respectively. Based on our findings and a comprehensive review of the literature, we refine the phenotype map for typical clinical findings of the terminal deletion 14q syndrome (i.e., intellectual disability/developmental delay, muscular hypotonia, postnatal growth retardation, microcephaly, congenital heart defects, genitourinary malformations, ocular coloboma, and several dysmorphic signs). Combining this phenotype map with benign copy-number variation data available from the Database of Genomic Variants, we propose a small region critical for certain features of the terminal deletion 14q syndrome which contains only seven RefSeq genes.     

Patient with terminal duplication 3q and terminal deletion 5q: comparison with the 3q duplication syndrome and distal 5q deletion syndrome

Partial duplication of chromosome 3q is a well-described condition of multiple congenital anomalies and developmental delay that resembles the Brachmann-de Lange syndrome. Similarly, an emerging phenotype of a distal 5q deletion syndrome has recently been described. The combination of both chromosome abnormalities has not been previously described. We report on a child with both a de novo duplication of distal 3q (q27 --> qter) and terminal deletion of 5q (q35.2 --> qter). The patient had facial anomalies, hypoplastic toenails, lymphedema of the dorsum of the feet, type I Chiari malformation, a seizure disorder, and moderate developmental delays. The phenotype is compared and contrasted to the few reports of patients with similar terminal 3q duplications and 5q deletions. Our patient did not have the characteristic phenotype of the 3q duplication syndrome, suggesting that the chromosome region responsible for this phenotype is more proximal than the terminal 3q27 region. In addition, comparison with three other reported cases of terminal 5q35 deletions suggests a possible association of terminal 5q deletions with central nervous system (CNS) structural abnormalities.     

Platelet dysfunction in a patient with the Opitz (BBBG) syndrome

An 11-year-old girl with Opitz (BBBG) syndrome presented with a bleeding disorder. Studies showed an immune-mediated qualitative platelet dysfunction in the absence of thrombocytopenia. This is the first report of hemostatic dysfunction in a patient with the Opitz (BBBG) syndrome. This report considers the possible relationship of the platelet dysfunction to the Opitz (BBBG) syndrome and its treatment. © 1992 Wiley-Liss, Inc.     

Ring chromosome 10 syndrome: case report and the possibility of clinical diagnosis

A 2-year-old boy, whose clinical abnormalities included growth retardation(3rd percentile), mild mental retardation (DQ = 67), microcephaly, hypertelorism, strabismus, prominent nasal bridge, stubby nose, pointed chin, undescended testes and hydronephrosis, had a ring chromosome 10. Using high-resolution banding technique, the breakpoints were decided at p15.3 and q26.3 of chromosome 10. The clinical features observed in this case were common in 8 other cases with ring chromosome 10 previously reported. Thus, the terminal deletion of both arms of chromosome 10 seems to be the cause of the specific clinical abnormalities. When a patient has the clinical common abnormalities above mentioned, ring chromosome 10 syndrome will be suspected before chromosome analysis.     

Opitz BBBG syndrome: new family with late-onset, serious complication

The Opitz BBBG syndrome is characterized by hypertelorism and (in male patients) hypospadias, in addition to a number of midline abnormalities: posterior laryngeal cleft, stridor, swallowing dysfunction, cardiac defects, imperforate anus, and urinary tract and CNS anomalies. Inheritance is autosomal dominant (McKusick number * 145410) with partial male sex limitation in most pedigrees. We report a Dutch family with Opitz BBBG syndrome in which the proband developed late-onset symptoms of a structural laryngeal abnormality.     

Phenotypic spectrum associated with SPECC1L pathogenic variants: new families and critical review of the nosology of Teebi,Opitz GBBB,and Baraitser-Winter syndromes

The SPECC1L protein plays a role in adherens junctions involved in cell adhesion, actin cytoskeleton organization, microtubule stabilization, spindle organization and cytokinesis. It modulates PI3K-AKT signaling and controls cranial neural crest cell delamination during facial morphogenesis. SPECC1L causative variants were first identified in individuals with oblique facial clefts. Recently, causative variants in SPECC1L were reported in a pedigree reported in 1988 as atypical Opitz GBBB syndrome. Six families with SPECC1L variants have been reported thus far. We report here eight further pedigrees with SPECC1L variants, including a three-generation family, and a further individual of a previously published family. We discuss the nosology of Teebi and GBBB, and the syndromes related to SPECC1L variants. Although the phenotype of individuals with SPECC1L mutations shows overlap with Opitz syndrome in its craniofacial anomalies, the canonical laryngeal malformations and male genital anomalies are not observed. Instead, individuals with SPECCL1 variants have branchial fistulae, omphalocele, diaphragmatic hernias, and uterus didelphis. We also point to the clinical overlap of SPECC1L syndrome with mild Baraitser-Winter craniofrontofacial syndrome: they share similar dysmorphic features (wide, short nose with a large tip, cleft lip and palate, blepharoptosis, retrognathia, and craniosynostosis), although intellectual disability, neuronal migration defect, and muscular problems remain largely specific to Baraitser-Winter syndrome. In conclusion, we suggest that patients with pathogenic variants in SPECC1L should not be described as “dominant (or type 2) Opitz GBBB syndrome”, and instead should be referred to as “SPECC1L syndrome” as both disorders show distinctive, non overlapping developmental anomalies beyond facial communalities.     

Microdeletion syndromes, balanced translocations, and gene mapping.

High resolution prometaphase chromosome banding has allowed the detection of discrete chromosome aberrations which escaped earlier metaphase examinations. Consistent tiny deletions have been detected in some well established malformation syndromes: an interstitial deletion in 15q11/12 in the majority of patients with the Prader-Willi syndrome and in a minority of patients with the Angelman (happy puppet) syndrome; a terminal deletion of 17p13.3 in most patients examined with the Miller-Dieker syndrome; an interstitial deletion of 8q23.3/24.1 in a large majority of patients with the Giedion-Langer syndrome; an interstitial deletion of 11p13 in virtually all patients with the WAGR (Wilms' tumour-aniridia-gonadoblastoma-retardation) syndrome; and an interstitial deletion in 22q11 in about one third of patients with the DiGeorge sequence. In addition, a combination of chromosome prometaphase banding and DNA marker studies has allowed the localisation of the genes for retinoblastoma and for Wilms' tumour and the clarification of both the autosomal recessive nature of the mutation and the possible somatic mutations by which the normal allele can be lost in retina and kidney cells. After a number of X linked genes had been mapped, discrete deletions in the X chromosome were detected by prometaphase banding with specific attention paid to the sites of the gene(s) in males who had from one to up to four different X linked disorders plus mental retardation. Furthermore, the detection of balanced translocations in probands with disorders caused by autosomal dominant or X linked genes has allowed a better insight into the localisation of these genes. In some females with X linked disorders, balanced X; autosomal translocations have allowed the localisation of X linked genes at the breakpoint on the X chromosome. Balanced autosome; autosome translocations segregating with autosomal dominant conditions have provided some clues to the gene location of these conditions. In two conditions, Greig cephalopolysyndactyly and dominant aniridia, two translocation families with one common breakpoint have allowed quite a confident location of the genes at the common breakpoint at 7p13 and 11p13, respectively.     

Another patient with a de novo deletion further delineates the 2q33.1 microdeletion syndrome

A male patient, who had intra-uterine growth retardation, a low birth weight and hypotonia due to a chromosome 2q33.1 deletion, is described. At the age of 20 years, he displays short stature, microcephaly, a high forehead, microstomia, large teeth and is hypertonic. He is severely mentally retarded, has not developed speech, is hyperactive, anxious and at times aggressive. Full tiling array showed a de novo 14 Mb deletion at chromosome region 2q32.3q33.2, further delineating the 2q33.1 microdeletion syndrome.     

Unbalanced translocation (15;17)(q13;p13.3) with apparent Prader-Willi syndrome but without Miller-Dieker syndrome

We studied after death a 3-month-old girl whose karyotype was 45,XX, ? 15, ? 17, + der(17),t(15;17)(q13;p13.3) and thus combines abnormalities of chromosome 15 associated with the Prader-Willi syndrome and of chromosome 17 associated with the Miller-Dieker syndrome. This infant had several manifestations of the Prader-Willi syndrome in infancy but none of the Miller-Dieker syndrome. We propose that essentially no loss of 17p material has occurred and confirm previous reports that the critical region for the production of the Miller-Dieker phenotype is located subterminally in the 17p13.3 region.