RUNX2-related metaphyseal dysplasia with maxillary hypoplasia: A rare skeletal disorder resembling SFRP4-related Pyle disease.

Metaphyseal dysplasia with maxillary hypoplasia with or without brachydactyly (MDMHB) is an ultra-rare skeletal dysplasia caused by heterozygous intragenic RUNX2 duplications, comprising either exons 3 to 5 or exons 3 to 6 of RUNX2. In this study, we describe a 14-year-old Belgian boy with metaphyseal dysplasia with maxillary hypoplasia but without brachydactyly. Clinical and radiographic examination revealed mild facial dysmorphism, dental anomalies, enlarged clavicles, genua valga and metaphyseal flaring and thin cortices with an osteoporotic skeletal appearance. Exome sequencing led to the identification of a de novo heterozygous tandem duplication within RUNX2, encompassing exons 3 to 7. This duplication is larger than the ones previously reported in MDMHB cases since it extends into the C-terminal activation domain of RUNX2. We review previously reported cases with MDMHB and highlight the resemblance of this disorder with Pyle disease, which may be explained by intersecting molecular pathways between RUNX2 and sFRP4. This study expands our knowledge on the genotypic and phenotypic characteristics of MDMHB and the role of RUNX2 in rare bone disorders.

[Genetic analysis of a Chinese pedigree affected with Brachydactyly type B1 due to a novel variant of ROR2 gene].

OBJECTIVE: To explore the genetic basis for a Chinese pedigree affected with Brachydactyly type B1 (BDB1) through whole exome sequencing (WES). METHODS: A BDB1 pedigree admitted to the Affiliated Women and Children's Hospital of Qingdao University on June 25, 2021 was selected as the study subject. Clinical data of the pedigree was collected with informed consent. WES was carried out for the proband, and candidate variant was verified by Sanger sequencing and bioinformatic analysis. RESULTS: WES and Sanger sequencing had identified a heterozygous c.2257delT variant in the ROR2 gene of the proband and his affected father, which has conformed to an autosomal dominant pattern of inheritance. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was classified to be likely pathogenic (PVS1_Strong+PM2 Supporting+PP4). CONCLUSION: The c.2257delT variant of the ROR2 gene was unreported previously and is strongly correlated with the BDB1-like phenotype in this pedigree. Above finding has enriched the mutational spectrum of the ROR2 gene and facilitated the diagnosis and genetic counseling for this pedigree.

Suppression of apoptosis impairs phalangeal joint formation in the pathogenesis of brachydactyly type A1.

Apoptosis occurs during development when a separation of tissues is needed. Synovial joint formation is initiated at the presumptive site (interzone) within a cartilage anlagen, with changes in cellular differentiation leading to cavitation and tissue separation. Apoptosis has been detected in phalangeal joints during development, but its role and regulation have not been defined. Here, we use a mouse model of brachydactyly type A1 (BDA1) with an IhhE95K mutation, to show that a missing middle phalangeal bone is due to the failure of the developing joint to cavitate, associated with reduced apoptosis, and a joint is not formed. We showed an intricate relationship between IHH and interacting partners, CDON and GAS1, in the interzone that regulates apoptosis. We propose a model in which CDON/GAS1 may act as dependence receptors in this context. Normally, the IHH level is low at the center of the interzone, enabling the "ligand-free" CDON/GAS1 to activate cell death for cavitation. In BDA1, a high concentration of IHH suppresses apoptosis. Our findings provided new insights into the role of IHH and CDON in joint formation, with relevance to hedgehog signaling in developmental biology and diseases.

A novel heterozygous mutation in PTHLH causing autosomal dominant brachydactyly type E complicated with short stature.

BACKGROUND: Brachydactyly type E (BDE) is a general term characterized by variable shortening of metacarpals and metatarsals, with phalanges affected frequently. It can occur as an isolated form or part of syndromes and manifest a high degree of phenotypic variability. In this study, we have identified the clinical characteristics and pathogenic causes of a four-generation pedigree with 10 members affected by BDE and short stature. METHODS: After the informed consent was signed, clinical data and peripheral blood samples were collected from available family members. Karyotype analysis, array-CGH, next-generation sequencing, and Sanger sequencing were employed to identity the pathogenic candidate gene. RESULTS: No translocation or microdeletion/duplication was found in karyotype analysis and array-CGH; hence, a novel heterozygous mutation, c.146dupA. p.S50Vfs*22, was detected by next-generation sequencing in PTHLH gene, leading to a premature stop codon. Subsequently, the mutation was confirmed by Sanger sequencing and co-segregation analysis. CONCLUSION: In this study, we described a novel heterozygous mutation (c.146dupA. p.S50Vfs*22) of gene PTHLH in a Chinese family. The mutation could induce a premature stop codon leading to a truncation of the protein. Our study broadened the mutation spectrum of PTHLH in BDE.

ADAM19 cleaves the PTH receptor and associates with brachydactyly type E.

Brachydactyly type E (BDE), shortened metacarpals, metatarsals, cone-shaped epiphyses, and short stature commonly occurs as a sole phenotype. Parathyroid hormone-like protein (PTHrP) has been shown to be responsible in all forms to date, either directly or indirectly. We used linkage and then whole genome sequencing in a small pedigree, to elucidate BDE and identified a truncated disintegrin-and-metalloproteinase-19 (ADAM19) allele in all affected family members, but not in nonaffected persons. Since we had shown earlier that the extracellular domain of the parathyroid hormone receptor (PTHR1) is subject to an unidentified metalloproteinase cleavage, we tested the hypothesis that ADAM19 is a sheddase for PTHR1. WT ADAM19 cleaved PTHR1, while mutated ADAM-19 did not. We mapped the cleavage site that we verified with mass spectrometry between amino acids 64-65. ADAM-19 cleavage increased Gq and decreased Gs activation. Moreover, perturbed PTHR1 cleavage by ADAM19 increased ß-arrestin2 recruitment, while cAMP accumulation was not altered. We suggest that ADAM19 serves as a regulatory element for PTHR1 and could be responsible for BDE. This sheddase may affect other PTHrP or PTH-related functions.

Reversal of cardiac and renal damage in a teenager with hypertension: A case report.

The authors describe the case of a 16-year-old male who was incidentally found to have a blood pressure of 200/? mmHg 6 months previously due to blurred vision and was diagnosed with "high risk of hypertension grade 3, renal insufficiency, hypertensive encephalopathy, hypertensive heart disease, and fundus hemorrhage" after relevant examinations were performed. His blood pressure fluctuated around 120/90 mmHg after beginning antihypertensive treatment. While the diagnostic work-up of his hypertension was inconclusive, he had severe hypertension with brachydactyly type E and short stature on physical examination. The patient's cardiac damage and renal insufficiency ultimately returned to normal after strict blood pressure control, suggesting that hypertension and brachydactyly syndrome alone do not cause cardiac and renal damage.

The pathogenic mechanism of syndactyly type V identified in a Hoxd13Q50R knock-in mice.

Syndactyly type V (SDTY5) is an autosomal dominant extremity malformation characterized by fusion of the fourth and fifth metacarpals. In the previous publication, we first identified a heterozygous missense mutation Q50R in homeobox domain (HD) of HOXD13 in a large Chinese family with SDTY5. In order to substantiate the pathogenicity of the variant and elucidate the underlying pathogenic mechanism causing limb malformation, transcription-activator-like effector nucleases (TALEN) was employed to generate a Hoxd13Q50R mutant mouse. The mutant mice exhibited obvious limb malformations including slight brachydactyly and partial syndactyly between digits 2-4 in the heterozygotes, and severe syndactyly, brachydactyly and polydactyly in homozygotes. Focusing on BMP2 and SHH/GREM1/AER-FGF epithelial mesenchymal (e-m) feedback, a crucial signal pathway for limb development, we found the ectopically expressed Shh, Grem1 and Fgf8 and down-regulated Bmp2 in the embryonic limb bud at E10.5 to E12.5. A transcriptome sequencing analysis was conducted on limb buds (LBs) at E11.5, revealing 31 genes that exhibited notable disparities in mRNA level between the Hoxd13Q50R homozygotes and the wild-type. These genes are known to be involved in various processes such as limb development, cell proliferation, migration, and apoptosis. Our findings indicate that the ectopic expression of Shh and Fgf8, in conjunction with the down-regulation of Bmp2, results in a failure of patterning along both the anterior-posterior and proximal-distal axes, as well as a decrease in interdigital programmed cell death (PCD). This cascade ultimately leads to the development of syndactyly and brachydactyly in heterozygous mice, and severe limb malformations in homozygous mice. These findings suggest that abnormal expression of SHH, FGF8, and BMP2 induced by HOXD13Q50R may be responsible for the manifestation of human SDTY5.

PRKD1-related telangiectasia-ectodermal dysplasia-brachydactyly-cardiac anomaly syndrome: Case report and review of the literature.

Telangiectasia-ectodermal dysplasia-brachydactyly-cardiac anomaly (TEBC) syndrome is a rare autosomal dominant condition, recently linked to the protein kinase D1 (PRKD1) gene. The phenotype of TEBC remains incomplete at this point. Our aim is to improve the characterization of the clinical and molecular aspects of the TEBC syndrome. We report on the 8th patient carrying a heterozygous de novo variation of PRKD1 c.2134G > A, p. (Val712Met) identified by trio exome sequencing. The proband presents with partial atrioventricular septal defect, brachydactyly, ectodermal dysplasia, telangiectasia that developed in childhood, intellectual disability with microcephaly, multicystic renal dysplasia and moderate hormonal resistance. In view of this 8th description and review of the literature, it appears that neurodevelopmental disorders and microcephaly are frequently associated with PRKD1 missense variants, adding to the four main clinical signs described initially in the TEBC syndrome. Further descriptions are required to confirm the observed endocrine and kidney abnormalities. This should contribute to a more comprehensive understanding of the phenotypic spectrum and may help establish genotype-phenotype correlations. In the context of genotype-first strategy, accurate patient descriptions are fundamental. Characterization of specific syndromic associations is essential for variant interpretation support and patient follow-up, even in very rare diseases, such as the TEBC syndrome.

Variants in both the N- or C-terminal domains of IHH lead to defective secretion causing short stature and skeletal defects.

BACKGROUND: Heterozygous Indian Hedgehog gene (IHH) variants are associated with brachydactyly type A1 (BDA1). However, in recent years, numerous variants have been identified in patients with short stature and more variable forms of brachydactyly. Many are located in the C-terminal domain of IHH (IHH-C), which lacks signaling activity but is critical for auto-cleavage and activation of the N-terminal (IHH-N) peptide. The absence of functional studies of IHH variants, particularly for those located in IHH-C, has led to these variants being classified as variants of uncertain significance (VUS). OBJECTIVE: To establish a simple functional assay to determine the pathogenicity of IHH VUS and confirm that variants in the C-terminal domain affect protein function. DESIGN/METHODS: In vitro studies were performed for 9 IHH heterozygous variants, to test their effect on secretion and IHH intracellular processing by western blot of cells expressing each variant. RESULTS: IHH secretion was significantly reduced in all mutants, regardless of the location. Similarly, intracellular levels of N-terminal and C-terminal IHH peptides were severely reduced in comparison with the control. Two variants present at a relatively high frequency in the general population also reduced secretion but to a lesser degree in the heterozygous state. CONCLUSIONS: These studies provide the first evidence that variants in the C-terminal domain affect the secretion capacity of IHH and thus, reduce availability of IHH ligand, resulting in short stature and mild skeletal defects. The secretion assay permits a relatively easy test to determine the pathogenicity of IHH variants. All studied variants affected secretion and interestingly, more frequent population variants appear to have a deleterious effect and thus contribute to height variation.

Síndrome oro-facial-digital / Oro-facial-digita syndrome

l síndrome orofaciodigital , es un grupo heterogéneo de trastornos del desarrollo de los cuales se han documentado al menos 13 variantes clínicas(1-3).Se transmite como un rasgo dominante ligado al cromosoma X. Se han reportado pocos casos en varones, ya que en general este trastorno genera letalidad en embriones masculinos en el primer o segundo semestre del embarazo (2).Conforma un cuadro clínicamente bien definido que debería ser reconocido en el recién nacido (4) y se asocia con manifestaciones clínicas a niveloral, facial y digital.El primer caso fue descrito por Mohr en 1941, seguido por un reporte de Papillon-League y Psaume en 1954; posteriormente, estos fueron denominados SOFD tipo 2 y 1, respectivamente (2,4).El SOFD tipo 1 a diferencia de los otros subtipos, es transmitido como un rasgo dominante ligado al cromosoma X. Es el único subtipo, del cual se ha identificado la mutación en el gen CXORF5, localizada en el brazo corto del cromosoma X (Xp22.2). El producto génico del SOFD1 es una proteína del centrosoma localizada en el cuerpo basal del cilio primario. (1-3,6). Se ha reportado una gran variabilidad clínica interfamiliar e intrafamiliar, así como 18 diferentes mutaciones en el SOFD 1 (6). La incidencia estimada es de 1: 50.000 a 250.000 nacidos vivos, afectando todas las razas por igual(2,5,6).Como su nombre lo indica, las principales manifestaciones se encuentran a nivel oral, facial y digital; sin embargo, otros órganos pueden estar afectados, lo que definiría el tipo específico de SOFD. Existen muy pocos casos reportados de los otros tipos, dada la amplia variabilidad en su expresión fenotípica; y también resulta muy dificultoso tipificar a los pacientes debido al solapamiento de las características clínicas (1-4). Entre las malformaciones orales se observan: labio superior muy corto, que suele acompañarse de una hendidura medial (45%) y frenillo grueso. El paladar se afecta con fisura medial amplia (80%) (Figs. 1 y 2); usualmente el paladar blando no existe, y en el óseo se presentan tres mamelones: uno central y dos laterales. El maxilar inferior dispone bandas fibrosas (frenillos) que adhieren los labios a las arcadas dentarias, las cuales están hendidas. Estas bandas se adhieren a la lengua fijándolas (anquiloglosia) y dividiéndola en varios mamelones (30-45%) (Figs. 1 y 2); muchas veces se encuentra tejido hamartomatoso (70%). El maxilar inferior también es hipoplásico y existe mala oclusión dentaria. (Fig. 2) Servin, Roxana y Col. Rev.Fac. Med. UNNE XXXVII: 1, 42-46, 2017Las malformaciones faciales incluyen: hipertelorismo, raíz nasal ancha con punta fina e hipoplasia de los cartílagos de las alas nasales; narinas pequeñas y antevertidas con diferencia de tamaño. También suelen apreciarse un aplanamiento mediofacial. La piel presenta millium en mejillas, frente y pabellón auricular (Figs. 1 y 2). Hay xerodermia y puede haber alopecía en cuero cabelludo. El pelo es seco y quebradizo. (Fig. 1)En miembros, las alteraciones más frecuentes se observan en manos (45%) tales como clinodactilia, braquidactilia y sindactilia. (Figs. 1 y 2)En los pies puede haber polisindactilia (casi siempre unilateral, preaxial). Los demás dedos son cortos e hipoplásicos. Fig. 1.Paciente de 10 meses, con los rasgos característicos. Arriba izq. labio superior fino, fisura palatina, mamelones linguales y milium en mejillas. Arriba der.clino y braquidactilia. Abajo: alopecia, cabello seco y quebradizo. Servin, Roxana y Col. Rev. Fac. Med. UNNE XXXVII: 1, 42-46, 2017A nivel de sistema nervioso central las malformaciones son variables (40%) puede existir porencefalia o hidrocefalia (que comúnmente se acompaña a agenesia total o parcial del cuerpo calloso), y su asociación con un retardo mental (40%). En aparato urinario se observan riñones poliquísticos en un 50% de los casos. El esqueleto también se ve afectado, evidenciándose huesos cortos y gruesos en manos y pies, muchas veces con osteoporosis (2-5,6).Los subtipos de este síndrome presentan características distintivas. La polidactilia se presenta en todos los subtipos, por lo que obviando esta característica, se menciona la Fig. 2.Madre de la paciente. Arriba izq. maloclusión dentaria, mamelones linguales y milium en mejillas. Arriba der. fisura palatina. Abajo: clino, braquidactilia, y en mano derecha sindactilia cutánea (membrana interdigital). Servin, Roxana y Col. Rev. Fac. Med. UNNE XXXVII: 1, 42-46, 2017clínica particular de los otros subtipos. El SOFD 1 es de carácter autosómico dominante ligado al X, predominando el millium y la poliquistosis renal. En el SOFD 2 (o Síndrome de Mohr-Majewski) se puede manifestar punta nasal bífida. La característica delSOFD 3 es el guiño ocular en sube y baja (alternado), los espasmos mioclónicos y el retraso mental. La nariz es bulbosa y las orejas son de implantación baja. En el SOFD 4 hay compromiso tibial, pectus excavatum y baja estatura. El SOFD 5 presenta fisura labial medial aislada. En el SOFD 6 (o Síndrome de Váradi-Papp) se distingue la polidactilia principalmente media y con metacarpos en forma de "Y"; también malformación cerebelar (ausencia de vermis). Se puede observar además displasia y agenesia renal (2).El SOFD 7 (o Síndrome de Whelan) fue reportado una sola vez, como un subtipo que compartía características del tipo 1 y 2. Durante el seguimiento, la paciente desarrolló clínica inherente al SOFD 1, por lo que se concluyó que inicialmente pertenecía al tipo 1, y se removió el SOFD 7 de la clasificación (8). El SOFD 8 es de herencia recesiva ligada al X. Clínicamente presenta, defectos tibiales, radiales y anormalidades epiglóticas. Por último, el SOFD 9 se caracteriza por anormalidades retinianas y fisura labial no medial (2).Es posible para el médico poder sospechar el diagnóstico de SOFD 1 mediante la fetoscopía o ultrasonografía, siendo la detección de polidactilia y defectos faciales, parámetros fundamentales; no obstante el diagnóstico es eminentemente clínico y debe hacerse en el recién nacido. Los diagnósticos diferenciales deben plantearse principalmente con subtipos de SOFD (2,4). Es de importancia la participación de un equipo multidisciplinario integrado por genetistas, pediatras, dermatólogos, cirujanos máxilo-faciales, psicólogos, odontopediatras para brindar asesoramiento y asistencia a estos pacientes. Aunque el pronóstico depende de las manifestaciones clínicas específicas y la gravedad de las mismas, es importante la identificación del tipo que presenta porque nos orientará en los estudios diagnósticos de otras posibles manifestaciones clínicas asociadas a ese tipo en particular (

Estudio de la braquidactilia en población gitana: descripción de un caso familiar / Estudo da braquidactilia da população cigana: Descrição de um caso familiar / Study of brachydactyly in gipsy population: Description of a familial case

La braquidactilia constituye una malformación genética heredable con carácter autosómico dominante o recesivo. En este artículo se describe el caso de una familia gitana que presentabraquidactlia congénita. El estudio se hizo en el Distrito Sanitario de Guadix en Granada. Los sujetos de estudio fueron cuatro hermanos (dos hombres y dos mujeres) integrantes de la misma unidad familiar y pertenecientes a la comunidad gitana. Se recogieron datos sociodemográficos y genéticos. Los sujetos presentan la manifestación de braquidactilia expresada fenotípicamente con alguna variabilidad entre ellos. Los datos radiológicos evidencian que corresponden a la braquidactilia tipo A4. Uno de ellos presenta una mezcla de A4 con E, o quizás se trate de una nueva variedad no clasificada. Todos presentan anomalías similares en los pies. Además, presentan obesidad, dislipidemia y diversos grados de consanguinidad...

Brachydactyly is an inheritable autosomal genetic malformation, either dominant or recessive. This article describes a gypsy family presenting with congenital brachydactyly. The study was conducted at the Sanitary District of Guadix, in Granada, Spain. The study subjects were four siblings (two women and two men), members of the same family and belonging to the Roma community. Demographic and genetic data were collected. With some variability, they had the phenotypic manifestation of brachydactyly. Radiographic data revealed that it was type A4 brachydactyly, but one of them featured a blend of A4 with E, or perhaps it is a new unclassified variety. All cases showed similar abnormalities in the feet. Besides, they are obese, and have dyslipidemia and different degrees of consanguinity...

A braquidactilia constitui uma malformação genética com caráter autossômico dominante ou recessiva. Este artigo descreve o caso de uma família cigana que apresenta braquidactlia congênitas. O estudo foi feito no Distrito de Sanitário de Guadix em Granada. Os sujeitos do estudo foram quatro irmãos (dois homens e duas mulheres) membros da mesma unidade familiar e pertencentes à comunidade cigana. Foram coletados dados demográficos e genéticos. Os sujeitos apresentam a manifestação de braquidactilia expressa fenotipicamente com alguma variabilidade entre eles. Os elementos radiológicos mostram que correspondem à braquidactilia tipo A4. Um deles apresenta uma mistura de A4, com E, ou, talvez, uma nova variedade não classificadas. Todos têm anomalias semelhantes nos pés. Ademais, apresentam obesidade, dislipidemia e diferentes graus de consanguinidade...

Braquidactilia tipo A4 / Brachydactyly type A4

Braquidactilia es un término que hace referencia a dedos desproporcionadamente cortos en manos y pies. Forma parte de las disostosis, un grupo de malformaciones caracterizadas por trastornos en el desarrollo óseo. En este trabajo se presenta un caso de una mujer con esta enfermedad, se discute su origen genético, manifestaciones clínicas, y pronóstico

Achados radiológicos na síndrome de Poland / Poland 's syndrome: radiologic findings

A síndrome de Poland é uma anomalia congênita rara não hereditária. Os autores descrevem os achados radiológicos clássicos da síndrome de Poland através de um relato de caso de um paciente masculino de quatro anos de idade com assimetria torácica e das mãos, ilustrando os critérios imaginológicos fundamentais para a conclusão diagnóstica.

Poland's syndrome is a rare non-inherited congenital anomaly. The authors describe the classic radiologic findings of Poland's syndrome by reporting the case of a male four-year old patient with asymmetry of hands and chest, illustrating the fundamental imaging criteria for a conclusive diagnosis.