Overlap of PIV syndrome, VACTERL and Pallister-Hall syndrome: clinical and molecular analysis

Simultaneous Endoscopic Management of Urethral Duplication and Postposterior Sagittal Anorectoplasty Urethral Diverticulum in a Boy with Anorectal Malformation

We report a case of urethral duplication with high anorectal malformation (ARM). A 12-year-old boy who had undergone transverse colostomy on day 2 of life and posterior sagittal anorectoplasty (PSARP) for ARM (rectobulbar fistula) at 8 years and also had urinary dribbling from a midscrotal opening in addition to normal voiding, presented with recurrent urinary tract infections and dysuria. Midscrotal dribbling had continued postoperatively. Colostomy had been closed 3 months after PSARP. Investigations revealed a large urethral diverticulum at the site of rectourethral fistula due to a segment of the gut being left behind during fistula closure. In addition, he had a sagittal urethral duplication originating at bulbar urethra and opening externally at midscrotum. The highlight of this report is successful endoscopic management of both the urethral duplication and the diverticulum.

Novel GLI3 Mutations in Chinese Patients with Non-syndromic Post-axial Polydactyly

BACKGROUND

Polydactyly, characterized by supernumerary digits in the upper or lower extremities, is the most common congenital digital abnormalities. It derives from the defective patterning of anteroposterior axis of the developing limb, with various etiology and clinical heterogeneity. The patients with post-axial polydactyly type A (PAPA) have the typical symptom of a well-formed supernumerary digit outside the fifth digit.

OBJECTIVE

The aim of present study was to identify the causative mutations of two unrelated Han Chinese patients with non-syndromic PAPA.

METHODS

Two unrelated Han Chinese patients and 100 ethnicity-matched, unrelated normal controls were recruited for this study. BGISEQ-500 exome sequencing was performed in the two patients, followed by validation in the patients and 100 controls by using Sanger sequencing.

RESULTS

Two mutations in the GLI family zinc finger 3 gene (GLI3), including a frameshift mutation c.3437_3453delTCGAGCAGCCCTGCCCC (p.L1146RfsX95) and a nonsense mutation c.3997C>T (p.Q1333X), were identified in two patients but were absent in the 100 healthy controls.

CONCLUSION

The two GLI3 mutations, p.L1146RfsX95 and p.Q1333X, may account for non-syndromic PAPA in the two patients, respectively. The findings of this study may expand the mutational spectrum of GLI3-PAPA and provide novel insights into the genetic basis of polydactyly.

Genetic factors in isolated and syndromic laryngeal cleft

A laryngotracheoesophageal cleft (LC) is a rare congenital anomaly of the upper aerodigestive tract resulting from the absence of fusion of the posterior cricoid lamina, which affects an abnormal communication between the larynx, trachea and esophagus. The genetic etiology of LC remains elusive. The involvement of genetic factors in the development of LC is suggested by reports of familial occurrence, and the increased prevalence of component features among first-degree relatives of affected individuals and murine knockout models. No consistent pattern of inheritance has been found in nonsyndromic patients, except for cases associated with described syndromes. Once the syndrome related to the laryngeal cleft is considered, an active search for the cleft must be initiated. The genetic evaluation of patients with LCs should be guided by the type and location of the malformation, specific medical history and a detailed physical examination. The application of genetic approaches, such as microarrays and exome sequencing might lead to elucidating the etiology of LCs.

The association between preaxial polydactyly and radial longitudinal deficiency in syndromic cases: a report on nine families

Preaxial polydactyly and radial longitudinal deficiency are usually viewed as two different entities. We present nine families with different disorders in which both preaxial polydactyly and radial longitudinal deficiency were seen in the phenotype. This indicates that both entities may be caused by the same developmental error or insult. The pathogenesis is complex and may be related to the interactions of two signalling loops: the first loop (named as the radial longitudinal deficiency loop) contains genes/proteins responsible for the development of the radial ray; and the second loop (named as the preaxial polydactyly loop) contains the Sonic Hedgehog involved in the pathogenesis of preaxial polydactyly. This entity is named as the preaxial polydactyly-radial longitudinal deficiency association and should be included in the description of the preaxial polydactyly spectrum.

LEVEL OF EVIDENCE

IV.

PhenoVar: a phenotype-driven approach in clinical genomics for the diagnosis of polymalformative syndromes

BACKGROUND

We propose a phenotype-driven analysis of encrypted exome data to facilitate the widespread implementation of exome sequencing as a clinical genetic screening test.Twenty test-patients with varied syndromes were selected from the literature. For each patient, the mutation, phenotypic data, and genetic diagnosis were available. Next, control exome-files, each modified to include one of these twenty mutations, were assigned to the corresponding test-patients. These data were used by a geneticist blinded to the diagnoses to test the efficiency of our software, PhenoVar. The score assigned by PhenoVar to any genetic diagnosis listed in OMIM (Online Mendelian Inheritance in Man) took into consideration both the patient's phenotype and all variations present in the corresponding exome. The physician did not have access to the individual mutations. PhenoVar filtered the search using a cut-off phenotypic match threshold to prevent undesired discovery of incidental findings and ranked the OMIM entries according to diagnostic score.

RESULTS

When assigning the same weight to all variants in the exome, PhenoVar predicted the correct diagnosis in 10/20 patients, while in 15/20 the correct diagnosis was among the 4 highest ranked diagnoses. When assigning a higher weight to variants known, or bioinformatically predicted, to cause disease, PhenoVar's yield increased to 14/20 (18/20 in top 4). No incidental findings were identified using our cut-off phenotypic threshold.

CONCLUSION

The phenotype-driven approach described could render widespread use of ES more practical, ethical and clinically useful. The implications about novel disease identification, advancement of complex diseases and personalized medicine are discussed.

Y-type urethral duplication in children: Management strategy at our center

Aims:

Report of seven children with Y-type urethral duplication (YUD).

Materials and Methods:

(A) Four staged operations were performed in patients having extensive perineal dissection (for rectourinary fistula separation and anterior mobilization of ventral urethra (VU)), tension rectocutaneous anastomosis, and children who were not toilet trained). These stages are (1) diversion sigmoid colostomy with anterior mobilization of VU as perineal urethrostomy via anterior sagittal approach; (2) Orthotopic urethral (OU) reconstruction; (3) anastomosis of OU and perineal urethra; (4) colostomy closure with management of complications. (B) The patients having VU onto the perineum underwent single stage urethral reconstruction.

Results:

The VU was urethrorectal/urethroanal in five and urethroperineal in two. Low anorectal malformation and upper urinary tract anomalies were present in 57.1% (4/7) and 14.7% (1/7) patients, respectively. Buccal mucosa free graft, transverse inner preputial flap, and perineal skin were tubularized for OU reconstruction. Mean age at 1^st , 2^nd , 3^rd , and 4^th surgery was 5 ± 0.78, 28 ± 0.78, 36 ± 0.78, 49 ± 0.78 months respectively. Three patients needed surgery for complications (urethrocutaneous fistula in two and urethral diverticulum in one) in a mean 3.12 ± 0.34 years of follow-up. Final uroflowmetry and fecal continence were good in all patients.

Conclusions:

The YUD is a difficult entity to manage. Although, staged procedure appears to be time consuming, but good and promising results can be achieved by staging the procedure.

Clinical geneticists' views of VACTERL/VATER association

VACTERL association (sometimes termed "VATER association" depending on which component features are included) is typically defined by the presence of at least three of the following congenital malformations, which tend to statistically co-occur in affected individuals: Vertebral anomalies, Anal atresia, Cardiac malformations, Tracheo-Esophageal fistula, Renal anomalies, and Limb abnormalities. Although the clinical criteria for VACTERL association may appear to be straightforward, there is wide variability in the way clinical geneticists define the disorder and the genetic testing strategy they use when confronted with an affected patient. In order to describe this variability and determine the most commonly used definitions and testing modalities, we present the results of survey responses by 121 clinical geneticists. We discuss the results of the survey responses, provide a literature review and commentary from a group of physicians who are currently involved in clinical and laboratory-based research on VACTERL association, and offer an algorithm for genetic testing in patients with this association.

VACTERL/VATER Association

VACTERL/VATER association is typically defined by the presence of at least three of the following congenital malformations: vertebral defects, anal atresia, cardiac defects, tracheo-esophageal fistula, renal anomalies, and limb abnormalities. In addition to these core component features, patients may also have other congenital anomalies. Although diagnostic criteria vary, the incidence is estimated at approximately 1 in 10,000 to 1 in 40,000 live-born infants. The condition is ascertained clinically by the presence of the above-mentioned malformations; importantly, there should be no clinical or laboratory-based evidence for the presence of one of the many similar conditions, as the differential diagnosis is relatively large. This differential diagnosis includes (but is not limited to) Baller-Gerold syndrome, CHARGE syndrome, Currarino syndrome, deletion 22q11.2 syndrome, Fanconi anemia, Feingold syndrome, Fryns syndrome, MURCS association, oculo-auriculo-vertebral syndrome, Opitz G/BBB syndrome, Pallister-Hall syndrome, Townes-Brocks syndrome, and VACTERL with hydrocephalus. Though there are hints regarding causation, the aetiology has been identified only in a small fraction of patients to date, likely due to factors such as a high degree of clinical and causal heterogeneity, the largely sporadic nature of the disorder, and the presence of many similar conditions. New genetic research methods offer promise that the causes of VACTERL association will be better defined in the relatively near future. Antenatal diagnosis can be challenging, as certain component features can be difficult to ascertain prior to birth. The management of patients with VACTERL/VATER association typically centers around surgical correction of the specific congenital anomalies (typically anal atresia, certain types of cardiac malformations, and/or tracheo-esophageal fistula) in the immediate postnatal period, followed by long-term medical management of sequelae of the congenital malformations. If optimal surgical correction is achievable, the prognosis can be relatively positive, though some patients will continue to be affected by their congenital malformations throughout life. Importantly, patients with VACTERL association do not tend to have neurocognitive impairment.

Y-type urethral duplication presented with perineal fistula in a boy

Urethral duplication is a rare congenital anomaly of the lower urinary system and has varied presentation. According to the Effmann classification, type IIA2-Y urethral duplication is characterized by the duplicated urethra originating from the bladder neck and opening into either the rectum or the perineum. The accessory urethra is normal and functional and the normally positioned dorsal urethra is hypoplastic and stenotic in unusual form of Y-type duplication. We present a new case with unusual form of Y-type duplication and discuss its treatment.

Molecular analysis expands the spectrum of phenotypes associated with GLI3 mutations

A range of phenotypes including Greig cephalopolysyndactyly and Pallister-Hall syndromes (GCPS, PHS) are caused by pathogenic mutation of the GLI3 gene. To characterize the clinical variability of GLI3 mutations, we present a subset of a cohort of 174 probands referred for GLI3 analysis. Eighty-one probands with typical GCPS or PHS were previously reported, and we report the remaining 93 probands here. This includes 19 probands (12 mutations) who fulfilled clinical criteria for GCPS or PHS, 48 probands (16 mutations) with features of GCPS or PHS but who did not meet the clinical criteria (sub-GCPS and sub-PHS), 21 probands (6 mutations) with features of PHS or GCPS and oral-facial-digital syndrome, and 5 probands (1 mutation) with nonsyndromic polydactyly. These data support previously identified genotype-phenotype correlations and demonstrate a more variable degree of severity than previously recognized. The finding of GLI3 mutations in patients with features of oral-facial-digital syndrome supports the observation that GLI3 interacts with cilia. We conclude that the phenotypic spectrum of GLI3 mutations is broader than that encompassed by the clinical diagnostic criteria, but the genotype-phenotype correlation persists. Individuals with features of either GCPS or PHS should be screened for mutations in GLI3 even if they do not fulfill clinical criteria.

Genetics of Hirschsprung disease and anorectal malformations

Hirschsprung disease (HD) and anorectal malformations (ARMs) result from alterations in hindgut development. It has long been recognized that both recur in families and thus result, at least in part, from genetic factors. Progress in the understanding of the genetic basis of HD has been made by the application of findings from genetic animal models of altered enteric nervous system development to human beings. Several genes have been shown to be important for human enteric nervous system development, and current work is progressing to identify genetic interactions that may explain the variable phenotype of HD. By contrast, understanding of the genetic factors underlying ARMs is much less developed. We and others have shown that genetic factors play an important role in the pathogenesis of ARMs, and many mouse genetic models suggest molecular pathways that may be altered in ARMs.

Y-type urethral duplication in the male

OBJECTIVE

To present a single series of Y-type duplication with an analysis of the presenting features, the management and outcome, as complete Y-type urethral duplication in the male is a rare congenital anomaly that presents many challenges.

PATIENTS AND METHODS

We retrospectively reviewed patient charts, identifying those with urethral duplication, and then those with complete Y-type duplication. The age at presentation, investigations, management and outcomes were reviewed.

RESULTS

Of 49 patients with a diagnosis of urethral duplication, 13 had the complete Y-type. Three were lost to follow-up and were therefore excluded from the study. The median (range) age at presentation was 2 months (birth to 10 years). All patients had other comorbidities, with anorectal malformations in seven, renal agenesis in four, sacral agenesis/partial agenesis in two, and unilateral/bilateral cryptorchidism in four. Presenting features included passage of urine perineally or rectally in seven, and dribbling from the orthotopic urethral meatus in one. The diagnosis was confirmed by micturating cysto-urethrography. A mean of 14 procedures was required to achieve a final complete repair, and included urethral reconstruction, repair of fistulae, urethral dilatation, and evaluative cystoscopy. Excluding cystoscopy and urethral dilatation, a mean (range) of 3 (1-5) reconstructive procedures was required in each patient. The median follow-up was 8 years. Five boys developed urethral strictures and one developed multiple fistulae. The best outcomes were in boys who had a staged urethral reconstruction.

CONCLUSION

Due to the strong association with other congenital anomalies we recommend that all patients should be evaluated thoroughly, including a detailed physical examination, renal tract ultrasonography and spinal radiography. Surgical management remains a significant challenge, requiring many procedures with unpredictable outcomes, the goals of which should be to maintain continence and reconstruct the urethra with good cosmesis. The optimum management scheme must be individualized in this rare condition.

Mapping phenotypes to language: a proposal to organize and standardize the clinical descriptions of malformations

Recent developments in molecular biology have markedly speeded the processes involved in determining the molecular etiology of human Mendelian disorders. Nowhere are these changes more evident than in the field that is variously termed molecular dysmorphology, human morphogenesis, or human developmental biology. In contrast to the rapid changes in molecular genetics analysis, the processes and approaches of the clinical component of molecular dysmorphology have not changed substantially, and clinical analysis is therefore becoming relatively slower than molecular discovery. If clinical discovery is to maintain its deserved position at the forefront of human genetics research, new methods must be developed to acquire, archive, and analyze these data. The limitations of current phenotyping, specifically, the limitations of the collection and archiving of clinical data in medical journal case reports and case series manuscripts are demonstrated. Several provocative approaches that have been proposed to advance the field of clinical analysis are reviewed. Lastly, a specific proposal for a system of clinical analysis and archiving of data on human pleiotropic developmental anomaly syndromes is proposed to address these limitations.

Pallister-Hall syndrome: Unreported skeletal features of aGLI3mutation

We describe two patients with Pallister-Hall syndrome (PHS), both with evidence of a generalized skeletal dysplasia as typified by upper and lower acromesomelic limb shortening and the previously unreported fibular hypoplasia, radio-ulnar bowing, and proximal epiphyseal hypoplasia. Genomic DNA was only available for sequencing analysis in patient 2 and the mutation, c.3386_3387delTT was detected in exon 14 of the GL13 gene. It is also possible that the findings in patient 1 represent the phenotypic expression of a novel GLI3 mutation. This report further expands the PHS phenotype and raises the possibility of specific GLI3 mutations resulting in more severe skeletal features. It also suggests that PHS should be included in the differential diagnosis of antenatally ascertained acromesomelic limb shortening and bowing with fibular hypoplasia particularly in the presence of polysyndactyly.

Molecular and clinical analyses of Greig cephalopolysyndactyly and Pallister-Hall syndromes: robust phenotype prediction from the type and position of GLI3 mutations

Mutations in the GLI3 zinc-finger transcription factor gene cause Greig cephalopolysyndactyly syndrome (GCPS) and Pallister-Hall syndrome (PHS), which are variable but distinct clinical entities. We hypothesized that GLI3 mutations that predict a truncated functional repressor protein cause PHS and that functional haploinsufficiency of GLI3 causes GCPS. To test these hypotheses, we screened patients with PHS and GCPS for GLI3 mutations. The patient group consisted of 135 individuals: 89 patients with GCPS and 46 patients with PHS. We detected 47 pathological mutations (among 60 probands); when these were combined with previously published mutations, two genotype-phenotype correlations were evident. First, GCPS was caused by many types of alterations, including translocations, large deletions, exonic deletions and duplications, small in-frame deletions, and missense, frameshift/nonsense, and splicing mutations. In contrast, PHS was caused only by frameshift/nonsense and splicing mutations. Second, among the frameshift/nonsense mutations, there was a clear genotype-phenotype correlation. Mutations in the first third of the gene (from open reading frame [ORF] nucleotides [nt] 1-1997) caused GCPS, and mutations in the second third of the gene (from ORF nt 1998-3481) caused primarily PHS. Surprisingly, there were 12 mutations in patients with GCPS in the 3' third of the gene (after ORF nt 3481), and no patients with PHS had mutations in this region. These results demonstrate a robust correlation of genotype and phenotype for GLI3 mutations and strongly support the hypothesis that these two allelic disorders have distinct modes of pathogenesis.

Ulnar/fibular ray defect and brachydactyly in a family: a possible new autosomal dominant syndrome

The ulnar-mammary syndrome (MIM 181450) includes postaxial ray defects, abnormalities of growth, delayed sexual development, and mammary and apocrine gland hypoplasia. Brachydactyly type E (MIM 113300) presents with shortening of the metacarpals and phalanges in the ulnar ray in association with moderately short stature. We describe a three-generation family with variable expression of ulnar/fibular hypoplasia, brachydactyly, ulnar ray defects and short stature. The proband had ulnar hypoplasia with missing IV-Vth fingers, fibular hypoplasia on the right, bilateral club feet, growth retardation, a hypoplastic mid-face, an ASD and hemangiomas. She had normal mammary tissue and normal sweating. The mother had short stature, midfacial hypoplasia, a hypoplastic ulna and hypoplasia of the IVth metacarpal (brachydactyly) on the right without other associated malformations. The maternal grandfather had mild bilateral fibular hypoplasia and midphalangeal brachydactyly of the IV-Vth toes. His sister had mild short stature and shortening of the IVth metacarpal of the left hand. Two-point linkage analysis with microsatellite markers spanning the Ulnar-Mammary locus at 12q24.1 did not confirm linkage. The patients may have a previously undescribed syndrome.

Polydactyly: how many disorders and how many genes?

Disorders that include polydactyly as a manifestation are diverse and numerous. Cataloging these disorders by phenotype and genotype demonstrates numerous overlapping phenotypes, genetic heterogeneity of phenotypes, and distinct phenotypes generated from mutations in single genes. To assess these issues, a list of disorders with polydactyly has been compiled from several sources. Among 119 disorders, 39 disorders are associated with mutations in genes, and among these, genotypic and phenotypic overlap is demonstrated. These issues highlight the need for a diagnostic system that catalogs both genotype and phenotype. Published 2002 Wiley-Liss, Inc.

The VACTERL association: lessons from the Sonic hedgehog pathway

VACTERL represents a non-random association of congenital anomalies in humans of poorly known etiology and pathogenesis. From our mutant analysis of Gli genes, which encode transcription factors mediating Sonic hedgehog (Shh) signal transduction, we observed that defective Shh signaling leads to a spectrum of developmental anomalies in mice strikingly similar to those of VACTERL. In this review, we will discuss the function of the three Gli transcription factors in Shh signaling and mammalian development. We propose that VACTERL could be caused by defective Shh signaling during human embryogenesis and suggest that the Gli mutant mice can serve as useful models for studying the pathogenesis of VACTERL.