Surviving campomelic dysplasia has the radiological features of the previously reported ischio-pubic-patella syndrome

Identifying pathogenic variants in the Follistatin-like 1 gene (FSTL1) in patients with skeletal and atrioventricular valve disorders

BACKGROUND

Follistatin-like 1 (Fstl1) is a glycoprotein expressed throughout embryonic development. Homozygous loss of Fstl1 in mice results in skeletal and respiratory defects, leading to neonatal death due to a collapse of the trachea. Furthermore, Fstl1 conditional deletion from the endocardial/endothelial lineage results in postnatal death due to heart failure and profound atrioventricular valve defects. Here, we investigated patients with phenotypes similar to the phenotypes observed in the transgenic mice, for variants in FSTL1.

METHODS

In total, 69 genetically unresolved patients were selected with the following phenotypes: campomelic dysplasia (12), small patella syndrome (2), BILU (1), and congenital heart disease patients (54), of which 16 also had kyphoscoliosis, and 38 had valve abnormalities as their main diagnosis. Using qPCR, none of 69 patients showed copy number variations in FSTL1. The entire gene body, including microRNA-198 and three validated microRNA-binding sites, were analyzed using Sanger sequencing.

RESULTS

No variants were found in the coding region. However, 8 intronic variants were identified that differed significantly in their minor allele frequency compared to controls. Variant rs2272515 was found to significantly correlate (p < 0.05) with kyphoscoliosis.

CONCLUSION

We conclude that pathogenic variants in FSTL1 are unlikely to be responsible for skeletal or atrioventricular valve anomalies in humans.

Spine malformation complex in 3 diverse syndromic entities: Case reports

RATIONALE

Clinical and radiographic phenotypic characterizations were the base line tool of diagnosis in 3 syndromic disorders in which congenital cervico-thoracic kyphosis was the major deformity.

PATIENTS CONCERNS

Directing maximal care toward the radiographic analysis is not only the axial malformation but also toward the appendicular abnormalities was our main concern. We fully documented the diversity of the spine phenotypic malformation complex via the clinical and radiographic phenotypes.

DIAGNOSES

We established the diagnosis via phenotypic/genotypic confirmation in 3 diverse syndromic entities namely acampomelic campomelic dysplasia, Larsen syndrome and Morquio syndrome type A (mucopolysaccharidosis type IV A).

INTERVENTIONS

Surgical interventions have been carried out in the Larsen syndrome and Morquio syndrome type A, resepectively.

OUTCOMES

The earliest the diagnosis is, the better the results are. The necessity to diagnose children in their first year of life has many folds, firstly the management would be in favor of the child's growth and development and secondly, the prognosis could be clearer to the family and the medical staff as well. Our current paper is to sensitize paediatricians, physicians and orthopedic surgeons regarding the necessity to detect the aetiological understanding in every child who manifests a constellation of malformation complex.

LESONS

Scoliosis and kyphosis/kyphoscoliosis are not a diagnosis in themselves. Such deformities are mostly a symptom complex correlated to dozens of types of syndromic associations. The rate curve progression and the final severity of congenital spine tilting are related to 3 factors: (a) the type of vertebral malformation present, (b) the patient's phenotype, and

Developmental dysplasia of the hip associated with aplasia of the pubic bone (hook-pelvis): report of a case and review of the literature

Aplasia of the pubic bone associated with congenital hip dislocation is rare. Various dysmorphic conditions featuring absence or hypoplasia of the ischiopubic bone, associated with congenital hip dislocation, have been distinguished in the literature. We report the case of an 18-month-old boy with developmental dysplasia of the hip associated with isolated total aplasia of the pubic bone. Patient was successfully treated with modified Salter osteotomy and reverse U-shaped capsuloplasty.

A novel SOX9 H169Q mutation in a family with overlapping phenotype of mild campomelic dysplasia and small patella syndrome

The phenotypic similarities have been demonstrated between non-lethal campomelic dysplasia (CD) and small patella syndrome (SPS), in which different genetic defects have been identified. We report on a familial case of skeletal dysplasia with overlapping phenotype of mild CD and SPS, including defective ischio-pubic ossification, elongated femoral neck, hypoplastic patellae, and increased space between the first and the second toes (sandal gap). Direct sequencing analysis demonstrated a novel missense mutation (p.H169Q) within the coding region of the SOX9 gene and negative for TBX4 mutations. Functional analysis of the p.H169Q mutant revealed reduced but not fully abolished transactivation capacity of the mutated protein. Retained residual SOX9 function might contribute to an extremely mild CD phenotype in the present cases. © 2013 Wiley Periodicals, Inc.

Mild Campomelic Dysplasia: Report on a Case and Review

We report on a 10.5-year-old girl with a mild form of campomelic dysplasia. She presented with short stature of prenatal onset, dysmorphic facial features, limitation of supination and pronation of the forearms, dysplastic nails, and bone abnormalities consisting especially of cone-shaped epiphyses of the middle phalanx of the 2nd fingers, brachydactyly and clinodactyly of the middle phalanx of both 5th fingers, short 4th metacarpals, radial and femoral head subluxation, hypoplastic scapulae, humeral and ulnar epiphyseal abnormalities, unossified symphysis pubis, and a significant delay in bone age. Molecular analysis of the SOX9 gene revealed the presence of a de novo missense mutation: p.P170L (c.509C>T). Mild and surviving cases of campomelic dysplasia are reviewed.

A case of campomelic dysplasia without sex reversal

Campomelic dysplasia (CD; OMIM #114290), a rare form of congenital short-limbed dwarfism, is due to mutations in SOX9, a member of the SOX (SRY-related HMG box) gene family. Multiparous mother at 38 weeks' gestation delivered a 3,272 g baby boy with characteristic phenotypes including bowing of the lower limbs, a narrow thoracic cage, 11 pairs of ribs, hypoplastic scapulae, macrocephaly, flattened supraorbital ridges and nasal bridge, cleft palate, and micrognathia. He underwent a tracheostomy at the age of three months for severe laryngomalacia after a number of repeated hospitalizations due to respiratory problems and died at the age of four months from progressive respiratory failure. He was diagnosed as having CD based on a novel frameshift mutation (p.Gln458ArgfsX12) in the SOX9 gene, the mutation which has not yet been reported in Korea.

Novel SOX9 Gene Mutation in Campomelic Dysplasia with Autosomal Sex Reversal

Campomelic dysplasia (CD; OMIM #114290) is an autosomal dominant, frequently lethal dysplasia syndrome whose primary features include angular bowing and shortening of the limbs, and sex reversal in the majority of affected XY individuals. Most CD cases have heterozygous de novo mutations in the coding region of the transcription factor gene SOX9 (SRY-related high-mobility group [HMG] box 9) in chromosome 17q. Here, we report a novel mutation of SOX9 in a female neonate with CD with autosomal sex reversal. Respiratory distress and cyanosis were noted at birth, and endotracheal intubation with mechanical ventilation was performed due to respiratory failure. The presenting phenotypes included dysmorphic face with macrocephaly, prominent forehead, low nasal bridge, cleft palate and micrognathia. Skeletal deformities characteristic of CD were observed, including narrow thoracic cage, hypoplastic scapulae, scoliosis and short limbs with anterolateral femoral and tibial bowing. The karyotype was 46,XY despite female external genitalia. SOX9 gene analysis revealed frameshift mutation (at nucleotide position 1095G-->AT) in the open reading frame, resulting in a frameshift with 211 new amino acids.

Human syndromes with congenital patellar anomalies and the underlying gene defects

Genetic disorders characterized by congenital patellar aplasia or hypoplasia belong to a clinically diverse and genetically heterogeneous group of lower limb malformations. Patella development involves different molecular and cellular mechanisms regulating dorso-ventral patterning, cartilage and bone formation along endochondral ossification pathways, and growth. Several human genes that are important for patella development have been uncovered by the study of human limb malformation syndromes, yet causative genes for many more such disorders await to be identified and their complex interactions in the developmental pathways deciphered. Mutant animal models of congenital patellar aplasia or hypoplasia are certainly instrumental to create more insight into this aspect of limb development. Moreover, investigation of the complete phenotype of human syndromes and animal models may reveal novel insights into the pleiotropic roles of the responsible genes in the normal developmental of other organ systems. In this review, the phenotype and gene defects of syndromes with congenital patellar aplasia or hypoplasia will be discussed, including the nail patella syndrome, small patella syndrome, isolated patella aplasia hypoplasia, Meier-Gorlin syndrome, RAPADILINO syndrome, and genitopatellar syndrome.

Fine mapping of chromosome 17 translocation breakpoints > or = 900 Kb upstream of SOX9 in acampomelic campomelic dysplasia and a mild, familial skeletal dysplasia

Previously, our group reported a five-generation family in which a balanced t(13;17) translocation is associated with a spectrum of skeletal abnormalities, including Robin sequence, hypoplastic scapulae, and a missing pair of ribs. Using polymerase chain reaction (PCR) with chromosome-specific markers to analyze DBA from somatic cell hybrids containing the derivative translocation chromosomes, we narrowed the breakpoint on each chromosome. Subsequent sequencing of PCR products spanning the breakpoints identified the breaks precisely. The chromosome 17 breakpoint maps approximately 932 kb upstream of the sex-determining region Y (SRY)-related high-mobility group box gene (SOX) within a noncoding transcript represented by two IMAGE cDNA clones. A growing number of reports have implicated chromosome 17 breakpoints at a distance of up to 1 Mb from SOX9 in some cases of campomelic dysplasia (CD). Although this multigeneration family has a disorder that shares some features with CD, their phenotype is significantly milder than any reported cases of (nonmosaic) CD. Therefore, this case may represent an etiologically distinct skeletal dysplasia or may be an extremely mild familial example of CD, caused by the most proximal translocation breakpoint from SOX9 reported to date. In addition, we have refined the breakpoint in a acampomelic CD case described elsewhere and have found that it lies approximately 900 kb upstream of SOX9.

New insights in congenital bowing of the femora

The aim of this study is to review the clinical, radiological and molecular findings of the bent bone dysplasia group including Stüve-Wiedemann syndrome due to LIFR mutations, Compomelic dysplasia due to SOX9 mutations and Kyphomelic dysplasia with no known molecular bases.

Mutations in the human TBX4 gene cause small patella syndrome

Small patella syndrome (SPS) is an autosomal-dominant skeletal dysplasia characterized by patellar aplasia or hypoplasia and by anomalies of the pelvis and feet, including disrupted ossification of the ischia and inferior pubic rami. We identified an SPS critical region of 5.6 cM on chromosome 17q22 by haplotype analysis. Putative loss-of-function mutations were found in a positional gene encoding T-box protein 4 (TBX4) in six families with SPS. TBX4 encodes a transcription factor with a strongly conserved DNA-binding T-box domain that is known to play a crucial role in lower limb development in chickens and mice. The present identification of heterozygous TBX4 mutations in SPS patients, together with the similar skeletal phenotype of animals lacking Tbx4, establish the importance of TBX4 in the developmental pathways of the lower limbs and the pelvis in humans.