Deciphering non-canonical WNT signaling has proven to be both fascinating and challenging. Discovered almost 30 years ago, non-canonical WNT ligands signal independently of the transcriptional co-activator β-catenin to regulate a wide range of morphogenetic processes during development. The molecular and cellular mechanisms that underlie non-canonical WNT function, however, remain nebulous. Recent results from various model systems have converged to define a core non-canonical WNT pathway consisting of the prototypic non-canonical WNT ligand, WNT5A, the receptor tyrosine kinase ROR, the seven transmembrane receptor Frizzled and the cytoplasmic scaffold protein Dishevelled. Importantly, mutations in each of these signaling components cause Robinow syndrome, a congenital disorder characterized by profound tissue morphogenetic abnormalities. Moreover, dysregulation of the pathway has also been linked to cancer metastasis. As new knowledge concerning the WNT5A-ROR pathway continues to grow, modeling these mutations will likely provide crucial insights into both the physiological regulation of the pathway and the etiology of WNT5A-ROR-driven diseases.

Human Robinow syndrome (RS) and dominant omodysplasia type 2 (OMOD2), characterized by skeletal limb and craniofacial defects, are associated with heterozygous mutations in the Wnt receptor FZD2. However, as FZD2 can activate both canonical and non-canonical Wnt pathways, its precise functions and mechanisms of action in limb development are unclear. To address these questions, we generated mice harboring a single-nucleotide insertion in Fzd2 (Fzd2em1Smill), causing a frameshift mutation in the final Dishevelled-interacting domain. Fzd2em1Smill mutant mice had shortened limbs, resembling those of RS and OMOD2 patients, indicating that FZD2 mutations are causative. Fzd2em1Smill mutant embryos displayed decreased canonical Wnt signaling in developing limb mesenchyme and disruption of digit chondrocyte elongation and orientation, which is controlled by the β-catenin-independent WNT5A/planar cell polarity (PCP) pathway. In line with these observations, we found that disruption of FZD function in limb mesenchyme caused formation of shortened bone elements and defects in Wnt/β-catenin and WNT5A/PCP signaling. These findings indicate that FZD2 controls limb development by mediating both canonical and non-canonical Wnt pathways and reveal causality of pathogenic FZD2 mutations in RS and OMOD2 patients.

Frizzled 2 (FZD2) is a transmembrane Wnt receptor. We previously identified a pathogenic human FZD2 variant in individuals with FZD2-associated autosomal dominant Robinow syndrome. The variant encoded a protein with a premature stop and loss of 17 amino acids, including a region of the consensus dishevelled-binding sequence. To model this variant, we used zygote microinjection and i-GONAD-based CRISPR/Cas9-mediated genome editing to generate a mouse allelic series. Embryos mosaic for humanized Fzd2W553* knock-in exhibited cleft palate and shortened limbs, consistent with patient phenotypes. We also generated two germline mouse alleles with small deletions: Fzd2D3 and Fzd2D4. Homozygotes for each allele exhibit a highly penetrant cleft palate phenotype, shortened limbs compared with wild type and perinatal lethality. Fzd2D4 craniofacial tissues indicated decreased canonical Wnt signaling. In utero treatment with IIIC3a (a DKK inhibitor) normalized the limb lengths in Fzd2D4 homozygotes. The in vivo replication represents an approach for further investigating the mechanism of FZD2 phenotypes and demonstrates the utility of CRISPR knock-in mice as a tool for investigating the pathogenicity of human genetic variants. We also present evidence for a potential therapeutic intervention.

This study presents the routine prosection findings of a 73-year-old male cadaver, with the cause of death reported to be hypertension and respiratory failure. Deep thorax and abdomen dissection exposed profound external and internal anatomical abnormalities. Externally, the body exhibited the following: pectus excavatum; short-limbed dwarfism; and abnormalities of the head, face, and external genitalia. Most of these findings suggest that the donor had Robinow syndrome, a rare genetic disorder involving developmental delay and skeletal abnormalities akin to those found in this cadaver. The internal gross anatomical findings included the following: megacolon; hiatal hernia; bilateral inguinal hernias; laterally displaced right kidney with a fibrous adhesion extending from the inferior pole of the kidney to the inguinal canal; atypical branching of the abdominal aorta; superiorly displaced diaphragm; pulmonary hypoplasia; heart right of midline; and curved esophagus. Although determining the exact etiology of megacolon is difficult in a cadaveric specimen, it is important to investigate the physiological changes associated with it. Therefore, the aim of this study was to investigate the space-occupying pathology of megacolon and to discuss a potential connection between megacolon and Robinow syndrome.

Genetic disorders can be monogenic or chromosomal. Deletions, duplications, and cryptic imbalances due to rearrangements of the telomeres are seen in a number of patients with psychomotor and language delay. Here, the authors report a case of 1-y-old boy born to nonconsanguineous couple who was evaluated for global developmental delay with phenotypic resemblance to a monogenic disorder namely Robinow syndrome. Cytogenetic microarray showed a double segment imbalance involving chromosome 6p25.3p25.2 and chromosome 8q23.3q24.3. Robinow syndrome also known as fetal face syndrome is a rare disorder with characteristic facial phenotype resembling fetal face with macrocephaly, low-set ears, broad great toes, gum hypertrophy, micropenis, and rhizomelia. Facial features include hypertelorism, wide mouth and short nose with upturned tip. It can have dominant or recessive mode of inheritance. The chromosomal abnormality in this case may provide clue to some novel gene for Robinow syndrome etiology.

Robinow syndrome is a rare entity with a characteristic appearance, such as hypertelorism, short stature, mesomelic shortening of the limbs, hypoplastic genitalia, and rib as well as vertebral anomalies. We had treated a patient with Robinow syndrome who developed hydrocephalus and craniosynostosis which is not usually associated.
The ventricle enlargement was detected during pregnancy in a female infant. She did not develop hydrocephalus just after birth. Her facial appearance was fetus-like, so the pediatricians had suspected Robinow syndrome. During follow-up examinations, a rapidly enlarging head circumference was detected when she was 3 months old. Her conscious level was not disturbed, but she had a tight fontanel and sunset phenomenon was recognized. Hydrocephalus was diagnosed by radiographic imaging so that she underwent ventriculo-peritoneal shunting (VPS). Her irregular head enlargement seized. Six months after surgery, her parents noticed the brachycephalic shape of her head. A computed tomography (CT) and magnetic resonance (MR) scan were conducted and showed that her bilateral coronal, bilateral lambdoid, and the sagittal suture were fused in addition with a tonsillar herniation. Since the sutures were not remaining, we diagnosed that this was a primary pan synostosis rather than secondary craniosynostosis due to VPS. Posterior cranial vault distraction with foramen magnum decompression (FMD) was conducted. The distractor was extended by 1 mm per day up to 30 mm. After a consolidation period of 2 months, the distractors were removed. Through this intervention, a 15.4% increase (+196cc) of the intracranial space with an improvement of the chronic tonsillar herniation was achieved.
To confirm the diagnosis of Robinow syndrome, a genetic test was conducted. The analysis showed ROR2 Exon3 (c233 c>t p. Thr 78 Met), which is found in the recessive type of Robinow syndrome. We report this patient as, to our best knowledge, the first case documented case of Robinow disease presenting with hydrocephalus and craniosynostosis. Posterior cranial vault distraction with FMD is a useful way to treat this condition.

Robinow syndrome (RS) is a rare heterogeneous disorder characterized by short stature, short-limbs, craniofacial, oro-dental abnormalities, vertebral segmentation defects, and frequently genital hypoplasia. Both autosomal dominant and recessive patterns of inheritance are observed with many causative genes. Here, we present the phenotypes and genotypes of four children with RS from different Indian families. Sequence variants were identified in genes ROR2, DVL1, and DVL3. Our results expand the mutational spectrum of RS and we also highlight the radiological changes in the radius and ulna in patients with ROR2 sequence variants which are primarily characteristic for ROR2 related RS but have been reported in WNT5A related RS.

Robinow syndrome (RS) is a rare, pleiotropic genetic disorder. While it has been reported that males with Robinow syndrome may have genitourinary atypicalities, these have not been systematically studied. We hypothesized that the underlying gene involved plays a role in the clinical variability of associated genital findings and that the phenotypic appearance of the genitalia in RS may have a psychological impact. Urologic-specific examination consisted of detailed examination and a questionnaire to investigate the psychological impact of the genital phenotype. Nine males agreed to a full evaluation. Average age was 19.9 years, penile length was 32.5 mm, stretched length 53 mm, and width 24.4 mm. Penile transposition occurred in all 9 male who allowed full examination. Undescended testicles were noted in 4/10, testicular atrophy in 5/9, buried penis in 7/9, hypospadias in 5/8, and a large penopubic gap (space between dorsum of penis base and pubic bone) in 5/6. In this cohort, 78% answered our semi-quantitative pilot questionnaire that identified diminished sexuality, sexual function, and self-perception. In conclusion, RS has unique, hallmark genital findings including penile transposition, buried penis, undescended testes, and large penopubic gaps. Genital phenotype in males was not shown to correlate with the specific gene involved for each patient. Surgical approaches and other interventions should be studied to address the findings of decreased sexuality and self-perception. It is the authors\' opinion that intervention to provide the appearance of penile lengthening be postponed until puberty to allow for maximal natural phallic growth.

Robinow syndrome is characterized by mesomelic limb shortening, hemivertebrae, and genital hypoplasia. Due to low prevalence and considerable phenotypic variability, it has been challenging to definitively characterize features of Robinow syndrome. While craniofacial abnormalities associated with Robinow syndrome have been broadly described, there is a lack of detailed descriptions of genotype-specific phenotypic craniofacial features. Patients with Robinow syndrome were invited for a multidisciplinary evaluation conducted by specialist physicians at our institution. A focused assessment of the craniofacial manifestations was performed by a single expert examiner using clinical examination and standard photographic images. A total of 13 patients with clinical and molecular diagnoses consistent with either dominant Robinow syndrome (DRS) or recessive Robinow syndrome (RRS) were evaluated. On craniofacial examination, gingival hyperplasia was nearly ubiquitous in all patients. Orbital hypertelorism, a short nose with anteverted and flared nares, a triangular mouth with a long philtrum, cleft palate, macrocephaly, and frontal bossing were not observed in all individuals but affected individuals with both DRS and RRS. Other anomalies were more selective in their distribution in this patient cohort. We present a comprehensive analysis of the craniofacial findings in patients with Robinow Syndrome, describing associated morphological features and correlating phenotypic manifestations to underlying genotype in a manner relevant for early recognition and focused evaluation of these patients.

Robinow syndrome, a rare genetic disorder, is characterized by skeletal dysplasia with, among other anomalies, extremity and hand anomalies. There is locus heterogeneity and both dominant and recessive inheritance. A detailed description of associated extremity and hand anomalies does not currently exist due to the rarity of this syndrome. This study seeks to document the hand anomalies present in Robinow syndrome to allow for improved rates of timely and accurate diagnosis. A focused assessment of the extremities and stature was performed using clinical examination and standard photographic images. A total of 13 patients with clinical and molecular diagnosis consistent with dominant Robinow syndrome or recessive Robinow syndrome were evaluated. All patients had limb shortening, the most common of which was mesomelia; however, rhizomelia and micromelia were also seen. These findings are relevant to clinical characterization, particularly as Robinow syndrome has classically been defined as a \"mesomelic disorder.\" A total of eight distinct hand anomalies were identified in 12 patients with both autosomal recessive and dominant forms of Robinow syndrome. One patient did not present with any hand differences. The most common hand findings included brachydactyly, broad thumbs, and clinodactyly. A thorough understanding of the breadth of Robinow syndrome-associated extremity and hand anomalies can aid in early patient identification, improving rates of timely diagnosis and allowing for proactive management of sequelae.