A Novel Mutation in a Gene Causes Sclerosteosis in a Family of Mediterranean Origin.

Background and Objectives: Sclerostin is an SOST gene product that inhibits osteoblast activity and prevents excessive bone formation by antagonizing the Wnt signaling pathway. Sclerosteosis has been linked to loss of function mutations in the SOST gene. It is a rare autosomal recessive disorder characterized by craniotubular hyperostosis and can lead to fatal cerebellar herniation. Our aim is to describe the clinical and radiological features and the new underlying SOST mutation in a patient with sclerosteosis. Case: A 25-year-old female who was referred to the endocrine clinic for suspected excess growth hormone. The patient complained of headaches, progressive blurred vision, hearing disturbances, increased size of feet, proptosis, and protrusion of the chin. She had normal antenatal history except for syndactyly. Images showed diffuse osseous thickening and high bone mineral density. Biochemical and hormonal tests were normal. Due to progressive compressive optic neuropathy, optic nerve fenestration with decompression hemicraniotomy was performed. Sclerosteosis was suspected due to the predominant craniotubular hyperostosis with syndactyly. Using peripheral leucocyte DNA, genomic sequencing of the SOST gene was performed. This identified a novel deletion homozygous mutation in the SOST gene (c.387delG, p.Asp131ThrfsTer116) which disrupts sclerostin function, causing sclerosteosis. Conclusions: Discovery of the molecular basis of sclerosteosis represents an important advance in the diagnosis and management of this fatal disease.

Clinical Characteristics of 90 Macrodactyly Cases.

PURPOSE: Macrodactyly is a rare, nonhereditary congenital deformity. Digital enlargement in macrodactyly involves all tissue types and presents alone or as part of a congenital deformity syndromes. Macrodactyly treatment largely depends on surgeons' experience and knowledge. Because there is a paucity of large cohort studies of macrodactyly in the literature, our goal was to retrospectively analyze macrodactyly cases in order to define a better system for diagnosis, classification, and prognosis. METHODS: Medical records of 90 Chinese macrodactyly patients, including demographic characteristics, clinical presentations, anatomical distributions, x-rays, pathological findings, and treatments, were reviewed. Genetic analyses of 12 patients were also reviewed. RESULTS: Disease incidence was similar across sex and geographical regions. Multiple-digit involvement was 2.6 times more frequent than single-digit involvement. The index finger, middle finger, and thumb were most commonly involved. Two digits were affected more often than 3, with the affected digits adjacent in most cases. The affected digit was in the median nerve innervation distribution in 79% of cases and was accompanied by enlargement and fat infiltration of the median nerve. Seven cases had syndactyly. Ten of the 12 cases subjected to PIK3CA mutation analysis were positive. CONCLUSIONS: Macrodactyly represents a heterogeneous group of conditions, without significant sex or geographical predilection, which is usually present at birth. A high PIK3CA mutation-positive rate in affected tissues suggests a similar cellular mechanism for overgrowth in patients with various clinical presentations. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

In vivo measurements of kidney glomerular number and size in healthy and Os/+ mice using MRI.

The development of chronic kidney disease (CKD) is associated with the loss of functional nephrons. However, there are no methods to directly measure nephron number in living subjects. Thus, there are no methods to track the early stages of progressive CKD before changes in total renal function. In this work, we used cationic ferritin-enhanced magnetic resonance imaging (CFE-MRI) to enable measurements of glomerular number (Nglom) and apparent glomerular volume (aVglom) in vivo in healthy wild-type (WT) mice (n = 4) and mice with oligosyndactylism (Os/+; n = 4), a model of congenital renal hypoplasia leading to nephron reduction. We validated in vivo measurements of Nglom and aVglom by high-resolution ex vivo MRI. CFE-MRI measured a mean Nglom of 12,220 ± 2,028 and 6,848 ± 1,676 (means ± SD) for WT and Os/+ mouse kidneys in vivo, respectively. Nglom measured in all mice in vivo using CFE-MRI varied by an average 15% from Nglom measured ex vivo in the same kidney (α = 0.05, P = 0.67). To confirm that CFE-MRI can also be used to track nephron endowment longitudinally, a WT mouse was imaged three times by CFE-MRI over 2 wk. Values of Nglom measured in vivo in the same kidney varied within ~3%. Values of aVglom calculated from CFE-MRI in vivo were significantly different (~15% on average, P < 0.01) from those measured ex vivo, warranting further investigation. This is the first report of direct measurements of Nglom and aVglom in healthy and diseased mice in vivo.

Truncating mutations of HIBCH tend to cause severe phenotypes in cases with HIBCH deficiency: a case report and brief literature review.

3-hydroxyisobutryl-CoA hydrolase (HIBCH) deficiency is a rare inborn error of valine metabolism characterized by neurodegenerative symptoms and caused by recessive mutations in the HIBCH gene. In this study, utilizing whole exome sequencing, we identified two novel splicing mutations of HIBCH (c.304+3A>G; c.1010_1011+3delTGGTA) in a Chinese patient with characterized neurodegenerative features of HIBCH deficiency and bilateral syndactyly which was not reported in previous studies. Functional tests showed that both of these two mutations destroyed the normal splicing and reduced the expression of HIBCH protein. Through a literature review, a potential phenotype-genotype correlation was found that patients carrying truncating mutations tended to have more severe phenotypes compared with those with missense mutations. Our findings would widen the mutation spectrum of HIBCH causing HIBCH deficiency and the phenotypic spectrum of the disease. The potential genotype-phenotype correlation would be profitable for the treatment and management of patients with HIBCH deficiency.

Case report of a novel nonsyndromic unilateral syndactyly of the hand.

Syndactyly is a cutaneous and/or bony digital malformation with possible webbing of adjacent fingers or toes and uni- or bilateral occurrence. We report an 84-year old woman with a novel non-syndromic congenital malformation of her left hand. Clinical examination showed that she only had four digits. Radiograph of the hand revealed synostosis of the second and third proximal phalanx, resulting in a triangular shaped bone with relatively normal articulations at both ends. The phalangeal base of the fused finger tapers distally and is broader than the middle phalangeal bases of the ring and little finger. This malformation does not fit in any of the known types of syndromic or non-syndromic syndactylies. Our case report highlights that radiological imaging is crucial for identification of bony syndactyly and correct classification of a given syndactyly. Knowledge of the different types of syndactylies is important because certain malformations may occur as a defining part of a syndromic disease.

Sclerosteosis caused by a novel nonsense mutation of SOST in a consanguineous family.

Sclerosteosis, characterized by the hyperostosis of cranial and tubular bones, is a rare autosomal recessive hereditary disorder caused by mutation of SOST gene. Four nonsense mutations of SOST have been identified worldwide. Here, we report two affected siblings who carried a novel nonsense mutation of SOST in a consanguineous family from China. The proband manifested typical symptoms of sclerosteosis, whereas the symptoms were absent in another affected sibling. Two nucleotide substitutions in exon 2 of SOST were identified, c.444_445TC>AA, resulting in a premature stop codon, p.Cys148→Stop. This truncated mutation loses 66 amino acid residues which contain 3 cysteine residues of the cysteine-knot motif, leading to loss of function of SOST. The symptoms of sclerosteosis may be clinically heterogeneous in some patients, even with the same mutation. Our results support the notion that founder effects from the ancestors contribute to the disease onset.

Fraser syndrome: features suggestive of prenatal diagnosis in a review of 38 cases.

OBJECTIVE: Fraser syndrome (FS) is a rare malformation recessive disorder. Major criteria are cryptophtalmos, syndactyly, respiratory, genital and urinary tract anomalies. Few prenatal presentations have been reported. METHOD: We analyzed the prenatal and postnatal fetal phenotype in 38 cases of FS, including 25 pregnancy termination cases, 8 intra-uterine death cases and 4 cases that died after birth. RESULTS: Including both prenatal and postnatal fetal phenotypic evaluation, all cases presented dysmorphic features with nose and ear dysplasia. Renal anomalies and syndactyly were present in 37/38 cases, cryptophtalmos in 36/38, airways anomalies in 30/37 and genital anomalies in 30/35 cases. Anomalies of the abdominal wall such as low set umbilicus and omphalocele were found in 31 cases. Among the 26 cases for which ultrasound data were available, detectable anomalies included oligohydramnios (22), ascites/hydrops (9), renal anomalies (20), evidence for high airways obstruction (11), ophthalmologic anomalies (4), ear dysplasia (2) and syndactyly (2). CONCLUSION: This study shows that the postnatal phenotype of FS is very specific, whereas oligohydramnios hampers the prenatal recognition of the cardinal FS diagnosis criteria. Association of oligohydramnios, kidney agenesis and CHAOS should lead to consider this diagnosis. © 2016 John Wiley & Sons, Ltd.

Familial pseudotail, scoliosis and synpolydactyly syndrome.

PURPOSE: This case series describes a novel condition characterized by familial pseudotail associated with scoliosis, and synpolydactyly that has not been previously reported in literature. METHODS: The authors present three siblings and one cousin from the same family living in the northern region of the Arabian Peninsula. All cases presented with pseudotail, scoliosis, and complex synpolydactyly. The authors demonstrated complete clinical and radiological descriptions in addition the detailed performed surgeries. RESULTS: The histopathological result of the resected pseudotail specimens revealed bony lesion covered with thick fibrous tissue and evidence of mature adipocytes within trabecular spaces. CONCLUSIONS: The described cases represent a novel condition that has not been previously reported in the literature. Familial pseudotail scoliosis synpolydactyly syndrome is a newly recognized form of familial pseudotail.

Idiopathic Fenestrated Complex Syndactyly in a Unique Crisscross Fashion.

This case presents surgical treatment of a unique form of syndactyly: an isolated fenestrated, complex, crisscross syndactyly of the right middle and ring fingers. A 2-year-old boy presented with the ring finger lying dorsal and the middle finger lying volar, with the middle phalanges syndactylized. A surgical release was performed with a subsequent z-plasty, 2 years later, for scar elongation. At the age of 4, he has essentially full function of his hand with minimal limitations. This case demonstrates that 2 digits that were syndactylized in a coronal plane (ring finger dorsal and middle finger volar) can be successfully surgically separated.

Compound heterozygosity for a frame shift mutation and a likely pathogenic sequence variant in the planar cell polarity­ciliogenesis gene WDPCP in a girl with polysyndactyly, coarctation of the aorta, and tongue hamartomas.

We report on a young girl with polysyndactyly, coarctation of the aorta, and tongue hamartomas. These features are similar to those reported in individuals with variant forms of orofaciodigital syndrome known as congenital heart defects, hamartomas of the tongue and polysyndactly (CHDHTP: OMIM 217085) [Örstavik et al., 1992] and orocardiodigital syndrome [Digilio et al., 1996]. Whole exome sequencing revealed that she is a compound heterozygote for a frame shift mutation and a likely pathogenic sequence variant in WDPCP, a gene that regulates planar cell polarity and ciliogenesis. Results of genotyping in her parents and unaffected siblings were consistent with autosomal recessive inheritance of the mutation and the WDPCP variant. These results suggest that disruption of planar cell polarity and ciliogenesis may result in this unusual form of orofaciodigital syndrome.

Microcephaly, ectodermal dysplasia, multiple skeletal anomalies and distinctive facial appearance: delineation of cerebro-dermato-osseous-dysplasia.

In 1980, a novel multiple malformation syndrome has been described in a 17-year-old woman with micro- and turricephaly, intellectual disability, distinctive facial appearance, congenital atrichia, and multiple skeletal anomalies mainly affecting the limbs. Four further sporadic patients and a couple of affected sibs are also reported with a broad clinical variability. Here, we describe a 4-year-old girl strikingly resembling the original report. Phenotype comparison identified a recurrent pattern of multisystem features involving the central nervous system, and skin and bones in five sporadic patients (including ours), while the two sibs and a further sporadic case show significant phenotypic divergence. Marked clinical variability within the same entity versus syndrome splitting is discussed and the term "cerebro-dermato-osseous dysplasia" is introduced to define this condition.

An infant with large fontanelles, aplasia cutis congenita, tessier facial cleft, polydactyly inversus, and toe syndactyly: a previously undescribed syndrome?

We report on a 5-month-old female with large and widely spaced anterior and posterior fontanelles, aplasia cutis congenita, Tessier 3 oblique facial cleft, polydactyly, and syndactyly of toes. The polydactyly is unusual as an accessory finger is attached to the left fifth finger with mirrored, end-to-end fusion. We are naming this anomaly "polydactyly inversus." The infant appears to have a previously unreported syndrome of unknown cause.

Sclerosteosis (craniotubular hyperostosis-syndactyly) with complex hyperphalangy of the index finger.

We report a 4-year-old boy with sclerosteosis associated with severe digital dysostosis. The initial medical consultation was prompted by bilateral, asymmetrical syndactyly of the index and middle fingers. The left index finger had complicated phalangeal anomalies: hyperphalangy (supernumerary phalanx distal to the middle phalanx) and hypoplasia with bracket epiphyses of the proximal and middle phalanges. Development of facial nerve palsy, hearing impairment and generalized osteosclerosis had occurred between 3 years and 4 years of age, with the subsequent identification of a homozygous SOST mutation. Bilateral second and third fingers syndactyly associated with abnormal patterning of the same fingers should be considered prodromal signs of sclerosteosis.

The Apert hand--angiographic planning of a single-stage, 5-digit release for all classes of deformity.

PURPOSE: To demonstrate the utility of computed tomography angiographic planning of a single-stage, complete release of syndactyly in Apert syndrome. METHODS: Computed tomography angiograms were performed as a preoperative planning tool in 6 patients. Five came to surgery. All had a single-stage operation for complete release of their syndactyly. RESULTS: Five patients, ranging from Upton type 1 to type 3 Apert hand deformities, have had preoperative computed tomography angiography that delineated the vascular anatomy. This allowed planning and execution of a single-stage syndactyly release in all patients. The preoperative imaging identified noteworthy abnormalities in vascular anatomy that were incorporated into surgical planning. CONCLUSIONS: The protocol presented allows preoperative planning and single-stage operation for complete release of syndactyly in patients with Apert syndrome.

Oculodentodigital dysplasia: ulnar-sided syndactyly and its associated disorders.

PURPOSE: Hand surgeons are often the first specialists to see patients with oculodentodigital dysplasia (ODDD), when infants with ulnar-sided syndactyly are referred. Major associated problems include neurologic, ophthalmologic, dental, and other skeletal abnormalities. The purposes of this study were to investigate the incidence of the reported associated conditions in the families of our patients with ODDD, correlate them with the severity of syndactyly, and provide better counseling with more accurate information for these patients and families. METHODS: We reviewed medical records from Texas Scottish Rite Hospital for Children from 1980 to 2009 to identify patients with ODDD. These patients and families were invited to return for a detailed medical and family history and physical examination documenting hand, foot, eye, dental, and facial findings. RESULTS: A total of 73 pediatric patients from 47 families were diagnosed with ODDD, and 38 individuals in 31 families agreed to participate in the study. We observed bilateral syndactyly in 32 patients, with symmetric involvement in 31 of these. Abnormalities of the shape and size of the middle phalanx of the small finger were common. Ophthalmological findings were present in 31 and dental abnormalities identified in 33 patients. Neurologic findings likely related to ODDD were found in 11 patients. There appeared to be an association between the severity of syndactyly and the severity of dental and urologic findings, but not ophthalmologic or neurologic findings such as paraparesis or cognitive deficits. CONCLUSIONS: We found a 29% incidence of neurologic manifestations in patients with ODDD. In addition, associated ophthalmologic, dental, and developmental conditions are frequent and a heightened awareness will allow appropriate referrals for patients with ulnar-sided syndactyly in ODDD. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

Subtle ultrasonographic appearance of Down's syndrome: a case report of prenatal diagnosis of isolated simple fetal syndactyly.

Syndactyly is an unusual condition in humans where two or more digits are fused together. In our report we present a case of prenatal diagnosis of simple, complete, bilateral syndactyly as the only ultrasonographic anomaly in a fetus with Down's syndrome. The mother, a 30-year-old, gravida 2, was referred to our hospital with an abnormal triple-test at 17 weeks of gestation, with a final biochemical risk for Down's syndrome more than 1:50. In this pregnancy neither the NT test nor early morphological exam showed typical findings of any chromosomal disorder. The patient underwent amniocentesis. We performed an accurate second level scan at 21 weeks while waiting for genetic results, and we suspected simple, complete, bilateral syndactyly between the third and fourth finger of the hands (rapper sign). The result of the invasive test was 47,XY,+21 and the mother opted for termination of pregnancy; the baby showed simple, complete, bilateral syndactyly of the two digits as suspected during sonography. In presenting our case report, we want to stress the importance of the accuracy of observation of fetal hand morphology, attitude, movements and reactivity. When the observation of fetal hands is not satisfactory (e.g., when the fetus does not open the fist), we recommend external stimulation of fetal reactivity through probe movements on the maternal abdomen (dynamic scan). This approach can make the identification of subtle hand anomalies easier and improve the detection rate of both structural and genetic fetal disorders.

Comparison of Vickers' Physiolysis With Osteotomy for Primary Correction of Clinodactyly.

Background: The purpose of this study was to compare the Vickers physiolysis procedure with osteotomy for correction of digital clinodactyly and determine which method provides better correction at final follow-up or whether the patient's age, preoperative angulation, or presence of syndactyly affects final outcomes. Methods: All patients of skeletal immaturity who underwent surgical correction of clinodactyly were evaluated with clinical examination and radiographs to determine the percentage and absolute change in the degree of clinodactyly pre- versus postoperatively, in addition to stratification based on the degree of deformity, age, and presence of syndactyly. Results: Vickers' physiolysis and osteotomy were undertaken in 30 and 11 digits, respectively. The angulation significantly improved from 43.0° to 23.9°, with a 46.2% correction of deformity in the Vickers group at 46.3 months. The angulation decreased from 39.2° to 22.4° in the osteotomy group, with a 55.3% correction of deformity at 55.3 months. There was better correction in those with isolated clinodactyly compared with those with concomitant syndactyly and better percentage of correction in patients with lesser deformity in the Vickers group. There were more reoperations in the osteotomy group. Conclusions: The use of osteotomy may lead to more revision cases, whereas the Vickers procedure has minimal complications and need for revision. The Vickers physiolysis procedure is more effective in those with angulation <55°.

Anatomical similarity between the Sost-knockout mouse and sclerosteosis in humans.

Sclerosteosis, a rare autosomal recessive genetic disorder caused by a mutation of the Sost gene, manifests in the facial skeleton by gigantism, facial distortion, mandibular prognathism, cranial nerve palsy, and, in extreme cases, compression of the medulla oblongata. Mice lacking sclerostin reflect some symptoms of sclerosteosis, but this is the first report of the effect on the facial skeleton. We used geometric morphometrics (GMM) to analyze the deformations of the murine facial skeleton from the wild-type to the Sost gene knockout. Landmark coordinates were obtained by surface reconstructions from micro-computed tomography. Centroid size, principal component scores in shape space and form space, and asymmetry were computed by the standard GMM formulas, and dental and skeletal jaw lengths were examined as ratios. We show here that, compared to wild type controls, mice lacking Sost have larger centroid size (effect size, p-value: 4.59, <.001), higher mean asymmetry (1.14, .065), dental and skeletal mandibular prognathism (1.36, .010 and 5.92, <.001), a smaller foramen magnum (-1.71, .015), and calvaria that are more highly curved (form space p = 4.09, .002; shape space p = 12.82, .002). These features of mice lacking sclerostin largely correspond to the changes of the facial skeleton observed in sclerosteosis. This alignment further supports claims that the Sost gene plays a fundamental role in bony facial development in rodents and humans alike.

Congenital radioulnar synostosis presenting in adulthood - a case report.

Congenital radioulnar synostosis is a rare developmental skeletal malformation of the upper limb, characterized by the fusion of the proximal ends of the radius and ulna from birth. The failure of prenatal longitudinal segmentation of the adjacent radius and ulna results in a fibrous bony bridge between the radius and ulna. We present a 23-year-old female who presented with pain and restricted mobility of the left elbow joint for 7 years. A plain X-ray was performed for the patient, revealing a diagnosis of congenital radio-ulnar synostosis. Careful evaluation of the anatomical relations and spatial orientation of bony structures is required for the diagnosis and treatment of such cases.