Genetics, Clinical Presentation, Radiological Features, and Midterm Outcome of Closing Wedge Osteotomy in Children With Brachydactyly Type C.

BACKGROUND: Brachydactyly (BD) type C is a rare form of familial BD caused by GDF5 mutations. Some of the affected children have severe clinodactyly requiring surgery. The literature is limited to case reports. PATIENTS AND METHODS: The current retrospective study included 15 Saudi Arabian families with 42 affected children seen by the author for 25 years. A total of 23 digits (in 23 hands) underwent surgical correction of clinodactyly using a closing wedge osteotomy. The current study reports on the genetics, clinical presentation, radiological features, and midterm outcome of surgery. RESULTS: Genetic analysis was done in 6 families and confirmed the presence of 2 novel missense mutations (p.Met173Val in 3 families and p.Thr203Asn in 3 families) in the GDF5 gene. All cases in the study group demonstrated the classical clinical and radiographic features of BD type C. However, only 1 hand showed all the features of angel-shaped bony defect. The clinodactyly defect was mostly observed in the index or middle fingers. Surgery for the clinodactyly defect was only done if there was finger overlap. Closing wedge osteotomy was done in a total of 23 digits with a satisfactory outcome. CONCLUSIONS: This study represents the largest reported series of children undergoing surgery for correction of BD type C clinodactyly with a uniform technique performed by a single surgeon. The closing wedge osteotomy used resulted in good midterm outcomes, although long-term follow-up is lacking.

Whole-exome sequencing identifies a de novo PDE3A variant causing autosomal dominant hypertension with brachydactyly type E syndrome: a case report.

BACKGROUND: Autosomal dominant hypertension with brachydactyly type E syndrome caused by pathogenic variants in the PDE3A gene was first reported in 2015. To date, there are only a few reports of this kind of syndrome. Other patients still lack a genetic diagnosis. CASE PRESENTATION: Whole-exome sequencing was performed in an 18-year-old female proband with a clinical diagnosis of hypertension with brachydactyly syndrome. Quantitative real-time PCR was used to identify pathogenic copy number variations (CNVs). After bioinformatics analysis and healthy control database filtering, we revealed a heterozygous missense PDE3A variant (c.1346G > A, p.Gly449Asp). The variant was absent in the ExAC database and located in a highly evolutionarily conserved cluster of reported PDE3A pathogenic variants. Importantly, this variant was predicted to affect protein function by both SIFT (score = 0) and PolyPhen-2 (score = 1). After Sanger sequencing, the variant was determined to be absent in the healthy parents of the proband as well as 800 ethnically and geographically matched healthy controls. CONCLUSION: We present a report linking a de novo PDE3A variant to autosomal dominant hypertension with brachydactyly type E syndrome.

Severe brachydactyly and short stature resulting from a novel pathogenic TRPS1 variant within the GATA DNA-binding domain.

Brachydactyly type E, which can be an isolated finding or part of a syndrome in combination with other clinical anomalies, involves metacarpals and metatarsals with or without short phalanges. Herein we report two unrelated Turkish females who presented with brachydactyly type E and vitamin D deficiency in the absence of marked alterations in serum calcium, phosphate, and parathyroid hormone. After excluding disease-causing variants in two candidate genes, PTHLH and PDE4D, we identified different pathogenic variants in TRPS1, the gene mutated in patients with tricho-rhino-phalangeal syndrome (TRPS). In one of the patients, who displayed severe brachydactyly and short stature, we identified a novel heterozygous missense pathogenic variant in exon 6 (c.2783A>G, p.Tyr928Cys), located within the GATA DNA-binding domain. The second patient, who had relatively milder brachydactyly and was of normal height, carried a heterozygous nonsense pathogenic variant in exon 4 (c. 1870C>T, p.Arg624Ter), which has been previously described. Both pathogenic variants segregated in affected family members. The patients additionally showed sparse hair and a bulbous nose, consistent with the clinical features of TRPS. Our findings, in addition to identifying the genetic cause of brachydactyly in two unrelated kindreds, emphasize the role of pathogenic TRPS1 variants in the development of brachydactyly type E and highlight the GATA DNA-binding region of TRPS1 protein with respect to phenotype-genotype correlation.

Prenatal and postnatal presentation of PRMT7 related syndrome: Expanding the phenotypic manifestations.

Protein arginine methyltransferase 7 (PRMT7) is a member of a family of enzymes that catalyze the transfer of methyl groups from S-adenosyl-l-methionine to nitrogen atoms on arginine residues. Arginine methylation is involved in multiple biological processes, such as signal transduction, mRNA splicing, transcriptional control, DNA repair, and protein translocation. Currently, 10 patients have been described with mutations in PRMT7. The shared findings include: hypotonia, intellectual disability, short stature, brachydactyly, and mild dysmorphic features. We describe the prenatal, postnatal, and pathological findings in two male sibs homozygote for a mutation in PRMT7. Both had intrauterine growth restriction involving mainly the long bones. In addition, eye tumor was found in the first patient, and nonspecific brain calcifications and a systemic venous anomaly in the second. The pregnancy of the first child was terminated and we describe the autopsy findings. The second child had postnatal growth restriction of prenatal onset, hypotonia, strabismus, sensorineural hearing loss, genitourinary and skeletal involvement, and global developmental delay. He had dysmorphic features that included frontal bossing, upslanting palpebral fissures, small nose with depressed nasal bridge, and pectus excavatum. Our patients provide additional clinical and pathological data and expand the phenotypic manifestations associated with PRMT7 homozygote/compound heterozygote mutations to include brain calcifications and delayed myelination, and congenital orbital tumor.

Non-ossifying fibroma with a pathologic fracture in a 12-year-old girl with tricho-rhino-phalangeal syndrome: a case report.

BACKGROUND: Tricho-rhino-phalangeal syndrome (TRPS) is a rare autosomal dominant genetic disorder characterized by distinctive craniofacial and skeletal abnormalities, while non-ossifying fibroma (NOF) is a common benign bone tumour in children and adolescents. To date, no case of TRPS coexisting with NOF has been reported. This report presents a 12-year-old girl who had the characteristic features of tricho-rhino-phalangeal syndrome and non-ossifying fibroma with a fibula fracture. CASE PRESENTATION: A 12-year-old girl was admitted to the Department of Endocrinology and Diabetes for evaluation of brachydactyly and a right fibula fracture. Clinical examination revealed sparse scalp hair, a characteristic bulbous pear-shaped nose, and brachydactyly with significant shortening of the fourth metatarsal. Neither intellectual disability nor multiple exostoses were observed. Radiography of both hands showed brachydactyly and cone-shaped epiphyses of the middle phalanges of the digits of both hands with deviation of the phalangeal axis. Genetic analysis of TRPS1 identified a heterozygous germline sequence variant (p.Ala932Thr) in exon 6 in the girl and her father. Approximately 1 month before being admitted to our department, the girl experienced a minor fall and suffered a fracture of the proximal fibula in the right lower limb. The pathological cytological diagnosis of the osteolytic lesion was NOF. Ten months following the surgery, the lesion on the proximal fibula of the girl disappeared. CONCLUSIONS: In conclusion, the present study is the first to report a rare case of NOF with a pathologic fracture in the fibula of a girl with TRPS. The identification of a missense mutation, (p.Ala932Thr), in exon 6 of TRPS1 in this kindred further suggested that the patient had type I TRPS and indicated that mutations in this exon may be correlated with more pronounced features of the syndrome. Radiological techniques and genetic analysis played key roles in the definitive diagnosis.

Otofaciocervical syndrome and metachondromatosis in a girl: Presentation of a novel association and remarks on clinical variability of branchial-arch disorders.

Otofaciocervical syndrome (OFCS) is a rare disorder characterized by facial, ear, branchial, and musculoskeletal anomalies, along with hearing loss and mild intellectual disability. Clinically, its distinction from branchiootorenal syndrome can be difficult. To date, the coexistence of OFCS and metachondromatosis has not been reported. Here, we describe a sporadic patient with both OFCS and metachondromatosis. This novel association prompts us to do some remarks on the clinical variability of branchial-arch disorders; in fact, our observations are consistent with the highly variable expressivity of OFCS and illustrate the need of a more accurate characterization of these branchial-arch disorders. In the meantime, involvement of clavicles, scapulae and shoulders remains a distinctive feature of OFCS.

[Evaluation of reparative osteogenesis of distraction regenerate of the fourth metatarsal bone in patients with brachymetatarsia]. / Otsenka reparativnogo osteogeneza distraktsionnogo regenerata chetvertoi plyusnevoi kosti u patsientov s brakhimetatarziei.

AIM: To evaluate reparative osteogenesis of the fourth metatarsal bone using X-ray and ultrasonic methods. MATERIAL AND METHODS: Six patients with fourth metatarsal bone dysplasia underwent ultrasound and X-ray examination during distraction and fixation. Data were analyzed. RESULTS: During distraction sonography assessed adequately the length of elongation, activity of bone trabecula formation, features of vascularization and organotypic reconstruction of regenerate. X-ray examination is advisable to determine the terms of device relief during fixation. CONCLUSION: Sonography is preferable during distraction for dynamic monitoring of reparative osteogenesis. X-ray examination is advisable to determine the terms of device relief during fixation.

Metaphyseal dysplasia with maxillary hypoplasia and brachydactyly in a Finnish woman: first confirmation of a duplication in RUNX2 as pathogenic variant.

Metaphyseal dysplasia with maxillary hypoplasia and brachydactyly (MDMHB) is an autosomal-dominant bone dysplasia that until now has only been reported in French Canadian individuals. We have recently identified an intragenic duplication in RUNX2, encompassing exons 3 to 5, as a cause of MDMHB in French Canadian families. Here we describe a 20-year-old Finnish woman who had typical clinical and radiological signs of MDMHB, the first reported individual with MDMHB who is not of French-Canadian origin. Copy number variant assays based on quantitative PCR of genomic DNA showed the presence of three copies within a part of RUNX2. Sequencing RUNX2 cDNA from the skin fibroblasts revealed a duplication of exons 3 to 5. The results demonstrated that the intronic breakpoints of the duplication differed from those previously found in the French Canadian family, but that the consequences on RUNX2 transcript were identical. These findings demonstrate that the MDMHB phenotype results from an intragenic duplication of RUNX2 exons 3 to 5 also outside of the community where the disorder was first identified.

Metacarpophalangeal joint locking in 3 family members with brachymesophalangy: case report.

We report painful locking of the metacarpophalangeal joint in a man, his mother, and his sister, all of whom have brachymesophalangy. Surgical excision of loose osteocartilaginous fragments relieved their symptoms. The fragments appeared to be unfused ossicles of the metacarpal head, unique to patients with brachymesophalangy.

A novel CHSY1 gene mutation underlies Temtamy preaxial brachydactyly syndrome in a Pakistani family.

Temtamy preaxial brachydactyly syndrome (TPBS) is an autosomal recessive rare disorder characterized by hyperphalangism of digits, facial dysmorphism, dental anomalies, sensorineural hearing loss, delayed motor and mental development, and growth retardation. Loss of function mutations have been recently reported in the CHSY1 gene to cause the TPBS. Here, we report a novel missense mutation (c.1897 G > A) in the CHSY1 gene in two TPBS patients from a consanguineous Pakistani family. The mutation predicted substitution of a highly conserved aspartate amino acid residue to asparagine at position 633 in the protein (D633N). Polyphen analysis supported the pathogenicity of D36N mutation. Our finding extends the body of recent evidence that supports the role of CHSY1 as a potential mediator of BMP signaling.

The Liebenberg syndrome: in depth analysis of the original family.

The Liebenberg syndrome was first described in 1973 in a five- generation family. A sixth generation was added in 2001, and in 2009 a hitherto unknown branch of the same family with similar anomalies extended the family tree significantly. This article describes the clinical findings and illustrates the abnormalities with radiographs and three-dimensional computed tomography scans. We discuss the genetic abnormality that causes Liebenberg syndrome, the genomic rearrangement at the PITX1 locus on chromosome 5.The structural variations seem to result in an ectopic expression of paired-like homeodomain transcription factor 1 (PITX1) in the forelimb causing a partial arm-to-leg transformation in these patients.

Embryology of familial (non-syndromic) brachydactyly of the hand.

Isolated familial non-syndromic brachydactyly is interesting from the embryological point of view because the phenotypes of isolated brachydactyly are frequently overlapping, yet they are caused by different gene mutations and the ring finger is frequently relatively preserved. We review the embryology of isolated familial brachydactyly with special attention to these two features.

Liebenberg syndrome: case report and insight into molecular basis.

We report a case of Liebenberg syndrome in a 6-year-old girl, including the clinical, radiological, angiographic, and operative findings. We note that the forearm and hand malformations have similarities to leg and foot anatomy. Our observations may help provide insight into the etiology of this unusual condition.

Metaphyseal dysplasia with maxillary hypoplasia and brachydactyly is caused by a duplication in RUNX2.

Metaphyseal dysplasia with maxillary hypoplasia and brachydactyly (MDMHB) is an autosomal-dominant bone dysplasia characterized by metaphyseal flaring of long bones, enlargement of the medial halves of the clavicles, maxillary hypoplasia, variable brachydactyly, and dystrophic teeth. We performed genome-wide SNP genotyping in five affected and four unaffected members of an extended family with MDMHB. Analysis for copy-number variations revealed that a 105 kb duplication within RUNX2 segregated with the MDMHB phenotype in a region with maximum linkage. Real-time PCR for copy-number variation in genomic DNA in eight samples, as well as sequence analysis of fibroblast cDNA from one subject with MDMHB confirmed that affected family members were heterozygous for the presence of an intragenic duplication encompassing exons 3 to 5 of RUNX2. These three exons code for the Q/A domain and the functionally essential DNA-binding runt domain of RUNX2. Transfection studies with murine Runx2 cDNA showed that cellular levels of mutated RUNX2 were markedly higher than those of wild-type RUNX2, suggesting that the RUNX2 duplication found in individuals with MDMHB leads to a gain of function. Until now, only loss-of-function mutations have been detected in RUNX2; the present report associates an apparent gain-of-function alteration of RUNX2 function with a distinct rare disease.

A misplaced lncRNA causes brachydactyly in humans.

Translocations are chromosomal rearrangements that are frequently associated with a variety of disease states and developmental disorders. We identified 2 families with brachydactyly type E (BDE) resulting from different translocations affecting chromosome 12p. Both translocations caused downregulation of the parathyroid hormone-like hormone (PTHLH) gene by disrupting the cis-regulatory landscape. Using chromosome conformation capturing, we identified a regulator on chromosome 12q that interacts in cis with PTHLH over a 24.4-megabase distance and in trans with the sex-determining region Y-box 9 (SOX9) gene on chromosome 17q. The element also harbored a long noncoding RNA (lncRNA). Silencing of the lncRNA, PTHLH, or SOX9 revealed a feedback mechanism involving an expression-dependent network in humans. In the BDE patients, the human lncRNA was upregulated by the disrupted chromosomal association. Moreover, the lncRNA occupancy at the PTHLH locus was reduced. Our results document what we believe to be a novel in cis- and in trans-acting DNA and lncRNA regulatory feedback element that is reciprocally regulated by coding genes. Furthermore, our findings provide a systematic and combinatorial view of how enhancers encoding lncRNAs may affect gene expression in normal development.

A novel mutation in CDMP1 causes brachydactyly type C with "angel-shaped phalanx". A genotype-phenotype correlation in the mutational spectrum.

Brachydactyly type C (BDC), a well-recognized autosomal dominant hand malformation, displays brachymesophalangy of the second, third, and fifth fingers, a short first metacarpal, hyperphalangy, and ulnar deviation of the index finger. An "angel-shaped phalanx" is a distinctive radiological sign that can be found in BDC and other skeletal dysplasias, such as angel-shaped phalango-epiphyseal dysplasia (ASPED), an autosomal dominant skeletal abnormality characterized by a typical angel-shaped phalanx, brachydactyly, specific radiological findings, abnormal dentition, hip dysplasia, and delayed bone age. BDC and ASPED result from mutations in the CDMP1 gene. We report here a Mexican patient with BDC and clinical features of ASPED who carries a novel mutation in CDMP1, confirming that BDC and ASPED are part of the CDMP1 mutational spectrum. Based on the large number of clinical features in common, we suggest that both anomalies are part of the same clinical spectrum. Supported by an extensive review of the literature, a possible genotype-phenotype correlation in the mutational spectrum of this gene is proposed.

Does brachydactyly have a protective effect on the erosive changes in rheumatoid arthritis?

OBJECTIVE: Brachydactyly (BD) is a general term for inappropriately short fingers and/or toes. The author previously reported that a short metacarpal bone had a protective effect on the metacarpophalangeal joint of the same finger in rheumatoid arthritis (RA). The objective was to investigate the prevalence of BD in patients with RA and its potential effect on the phenotype, especially erosive changes. METHODS: A total of 1524 Korean patients with RA were recruited. The presence of BD on hand radiographs, rheumatoid factor (RF), anti-cyclic citrullinated peptide antibody (anti-CCP), HLA-DRB1 shared epitopes (SE), risk haplotypes of peptidyl deiminase type IV (PADI4) and erosive joint stage, and smoking status, were determined. RESULTS: The prevalence of BD was 7.9% (n=120) in our RA cohort. The types of BD were type A3 (79.2%), type D (15.0%), Kirner deformity (14.2%), and type E (6.7%). RA patients with BD had reduced erosion on hand radiographs (OR=0.57, 95% CI: 0.34-0.95, p=0.029) adjusted for age, sex, disease duration, smoking, RF, anti-CCP, SE, and PADI4. CONCLUSION: BD is more common in RA patients than might be expected. BD may have a protective effect on erosive changes in RA independent of previously well-established risk factors such as seropositivity, SE, PADI4, and smoking.