A mesomelic skeletal dysplasia, Kantaputra-like, not related to HOXD cluster region, and with phenotypic gender differences.

Mesomelic skeletal dysplasia is a heterogeneous group of skeletal disorders that has grown since the molecular basis of these conditions is in the process of research and discovery. Here, we report a Brazilian family with eight affected members over three generations with a phenotype similar to mesomelic Kantaputra dysplasia. This family presents marked shortening of the upper limbs with hypotrophy of the lower limbs and clubfeet without synostosis. Array-based CNV analysis and exome sequencing of four family members failed to show any region or gene candidate. Interestingly, males were more severely affected than females in this family, suggesting that gender differences could play a role in the phenotypic expressivity of this condition.

Czech dysplasia mimicking rheumatoid arthritis: Case series and literature review.

OBJECTIVE: This study reported a family with most members affected by Czech dysplasia. We examined the patients' clinical, laboratory, and imaging characteristics and evaluated their functional capacity using the Stanford Health Assessment Questionnaire-Disability Index. METHODS: The method used was case series description and literature review. RESULTS: This study showed that the pathogenic variant c.823C>T in the COL2A1 gene, which is a characteristic of Czech dysplasia, was found in 12 Brazilian individuals. Half of the patients in this family met the criteria for rheumatoid arthritis (RA) based on the 2010 American College of Rheumatology/European League Against Rheumatism classification criteria. Patients had arthritis in their hand joints, synovitis detected by ultrasound, and alterations in inflammatory tests. The Stanford Health Assessment Questionnaire-Disability Index assessment revealed that all patients exhibited moderate-to-severe functional disability. What distinguish Czech dysplasia from RA are an autosomal dominant inheritance pattern, platyspondyly, sensorineural hearing loss, and shortening of the metatarsal bones. CONCLUSIONS: It is important to consider Czech dysplasia as a potential differential diagnosis for RA. This autosomal dominant skeletal dysplasia is associated with normal height, short metatarsals, platyspondyly, hearing loss, enlarged epiphyses, and precocious osteoarthritis. Inflammatory findings such as arthritis, synovitis, and alteration of inflammatory markers may also be present in individuals with Czech dysplasia.

Achondroplasia in Latin America: practical recommendations for the multidisciplinary care of pediatric patients.

BACKGROUND: Achondroplasia is the most common bone dysplasia associated with disproportionate short stature, and other comorbidities, such as foramen magnum stenosis, thoracolumbar kyphosis, lumbar hyperlordosis, genu varum and spinal compression. Additionally, patients affected with this condition have higher frequency of sleep disorders, ear infections, hearing loss and slowed development milestones. Considering these clinical features, we aimed to summarize the regional experts' recommendations for the multidisciplinary management of patients with achondroplasia in Latin America, a vast geographic territory with multicultural characteristics and with socio-economical differences of developing countries. METHODS: Latin American experts (from Argentina, Brazil, Chile and Colombia) particiáted of an Advisory Board meeting (October 2019), and had a structured discussion how patients with achondroplasia are followed in their healthcare centers and punctuated gaps and opportunities for regional improvement in the management of achondroplasia. RESULTS: Practical recommendations have been established for genetic counselling, prenatal diagnosis and planning of delivery in patients with achondroplasia. An outline of strategies was added as follow-up guidelines to specialists according to patient developmental phases, amongst them neurologic, orthopedic, otorhinolaryngologic, nutritional and anthropometric aspects, and related to development milestones. Additionally, the role of physical therapy, physical activity, phonoaudiology and other care related to the quality of life of patients and their families were discussed. Preoperative recommendations to patients with achondroplasia were also included. CONCLUSIONS: This study summarized the main expert recommendations for the health care professionals management of achondroplasia in Latin America, reinforcing that achondroplasia-associated comorbidities are not limited to orthopedic concerns.

New SHH and Known SIX3 Variants in a Series of Latin American Patients with Holoprosencephaly.

Holoprosencephaly (HPE) is the failure of the embryonic forebrain to develop into 2 hemispheres promoting midline cerebral and facial defects. The wide phenotypic variability and causal heterogeneity make genetic counseling difficult. Heterozygous variants with incomplete penetrance and variable expressivity in the SHH, SIX3, ZIC2, and TGIF1 genes explain ∼25% of the known causes of nonchromosomal HPE. We studied these 4 genes and clinically described 27 Latin American families presenting with nonchromosomal HPE. Three new SHH variants and a third known SIX3 likely pathogenic variant found by Sanger sequencing explained 15% of our cases. Genotype-phenotype correlation in these 4 families and published families with identical or similar driver gene, mutated domain, conservation of residue in other species, and the type of variant explain the pathogenicity but not the phenotypic variability. Nine patients, including 2 with SHH pathogenic variants, presented benign variants of the SHH, SIX3, ZIC2, and TGIF1 genes with potential alteration of splicing, a causal proposition in need of further studies. Finding more families with the same SIX3 variant may allow further identification of genetic or environmental modifiers explaining its variable phenotypic expression.

Femoral-facial syndrome: A review of the literature and 14 additional patients including a monozygotic discordant twin pair.

Femoral-facial syndrome (FFS, OMIM 134780), also known as femoral hypoplasia-unusual face syndrome, is a rare sporadic syndrome associated with maternal diabetes, and comprising femoral hypoplasia/agenesis and a distinct facies characterized by micrognathia, cleft palate, and other minor dysmorphisms. The evaluation of 14 unpublished Brazilian patients, prompted us to make an extensive literature review comparing both sets of data. From 120 previously reported individuals with FFS, 66 were excluded due to: not meeting the inclusion criteria (n = 21); not providing sufficient data to ascertain the diagnosis (n = 29); were better assigned to another diagnosis (n = 3); and, being fetuses of the second trimester (n = 13) due to the obvious difficult to confirm a typical facies. Clinical-radiological and family information from 54 typical patients were collected and compared with the 14 new Brazilian patients. The comparison between the two sets of patients did not show any relevant differences. Femoral involvement was most frequently hypoplasia, observed in 91.2% of patients, and the typical facies was characterized by micrognathia (97%), cleft palate (61.8%), and minor dysmorphisms (frontal bossing 63.6%, short nose 91.7%, long philtrum 94.9%, and thin upper lip 92.3%). Clubfoot (55.9%) was commonly observed. Other observed findings may be part of FFS or may be simply concurrent anomalies since maternal diabetes is a common risk factor. While maternal diabetes was the only common feature observed during pregnancy (50.8%), no evidence for a monogenic basis was found. Moreover, a monozygotic discordant twin pair was described reinforcing the absence of a major genetic factor associated with FFS.

Homozygous deletion in MYL9 expands the molecular basis of megacystis-microcolon-intestinal hypoperistalsis syndrome.

Megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) is a severe disease characterized by functional obstruction in the urinary and gastrointestinal tract. The molecular basis of this condition started to be defined recently, and the genes related to the syndrome (ACTG2-heterozygous variant in sporadic cases; and MYH11 (myosin heavy chain 11), LMOD1 (leiomodin 1) and MYLK (myosin light chain (MLC) kinase)-autosomal recessive inheritance), encode proteins involved in the smooth muscle contraction, supporting a myopathic basis for the disease. In the present article, we described a family with two affected siblings with MMIHS born to consanguineous parents and the molecular investigation performed to define the genetic etiology. Previous whole exome sequencing of the affected child and parents did not identify a candidate gene for the disease in this family, but now we present a reanalysis of the data that led to the identification of a homozygous deletion encompassing the last exon of MYL9 (myosin regulatory light chain 9) in the affected individual. MYL9 gene encodes a regulatory myosin MLC and the phosphorylation of this protein is a crucial step in the contraction process of smooth muscle cell. Despite the absence of human or animal phenotype related to MYL9, a cause-effect relationship between MYL9 and the MMIHS seems biologically plausible. The present study reveals a strong candidate gene for autosomal recessive forms of MMIHS, expanding the molecular basis of this disease and reinforces the myopathic basis of this condition.

Molecular analysis of the CTSK gene in a cohort of 33 Brazilian families with pycnodysostosis from a cluster in a Brazilian Northeast region.

BACKGROUND: Pycnodysostosis is an autosomal recessive skeletal dysplasia, the prevalence of which is estimated to be low (1 per million). Nevertheless, in recent years we have found 27 affected individuals from 22 families in Ceará State, a region of the Brazilian Northeast, giving a local prevalence of 3 per million. This local prevalence associated with a high parental consanguinity, suggesting a possible founder effect, prompted us to perform a molecular investigation of these families to test this hypothesis. METHODS: The CTSK gene was sequenced by the Sanger method in the patients and their parents. In addition to 18 families from Ceará, this study also included 15 families from other Brazilian regions. We also investigated the origin of each family from the birthplace of the parents and/or grandparents. RESULTS: We have studied 39 patients, including 33 probands and 6 sibs, from 33 families with pycnodysostosis and identified six mutations, five previously described (c.436G>C, c.580G>A, c.721C>T, c.830C>T and c.953G>A) and one novel frameshift (c.83dupT). This frameshift variant seems to have a single origin in Ceará State, since the haplotype study using the polymorphic markers D1S2344, D1S442, D1S498 and D1S2715 suggested a common origin. Most of the mutations were found in homozygosity in the patients from Ceará (83.3 %) while in other states the mutations were found in homozygosity in half of patients. We have also shown that most of the families currently living outside of Ceará have northeastern ancestors, suggesting a dispersion of these mutations from the Brazilian Northeast. CONCLUSIONS: The high frequency of pycnodysostosis in Ceará State is the consequence of the high inbreeding in that region. Several mutations, probably introduced a long time ago in Ceará, must have spread due to consanguineous marriages and internal population migration. However, the novel mutation seems to have a single origin in Ceará, suggestive of a founder effect.

Visceral myopathy: Clinical and molecular survey of a cohort of seven new patients and state of the art of overlapping phenotypes.

Visceral motility dysfunction is a key feature of genetic disorders such as megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS, MIM moved from 249210 to 155310), chronic intestinal pseudo-obstruction (CIPO, MIM609629), and multisystemic smooth muscle dysfunction syndrome (MSMDS, MIM613834). The genetic bases of these conditions recently begun to be clarified with the identification of pathogenic variants in ACTG2, ACTA2, and MYH11 in individuals with visceral motility dysfunction. The MMIHS was associated with the heterozygous variant in ACTG2 and homozygous variant in MYH11, while the heterozygous variant in ACTA2 was observed in patients with MSMDS. In this study, we describe the clinical data as well as the molecular investigation of seven individuals with visceral myopathy phenotypes. Five patients presented with MMIHS, including two siblings from consanguineous parents, one had CIPO, and the other had MSMDS. In three individuals with MMIHS and in one with CIPO we identified heterozygous variant in ACTG2, one being a novel variant (c.584C>T-p.Thr195Ile). In the individual with MSMDS we identified a heterozygous variant in ACTA2. We performed the whole-exome sequencing in one sibling with MMIHS and her parents; however, the pathogenic variant responsible for her phenotype could not be identified. These results reinforce the clinical and genetic heterogeneity of the visceral myopathies. Although many cases of MMIHS are associated with ACTG2 variants, we suggest that other genes, besides MYH11, could cause the MMIHS with autosomal recessive pattern. © 2016 Wiley Periodicals, Inc.

Frequency of the allelic variant c.1150T > C in exon 10 of the fibroblast growth factor receptor 3 (FGFR3) gene is not increased in patients with pathogenic mutations and related chondrodysplasia phenotypes.

Mutations in the FGFR3 gene cause the phenotypic spectrum of FGFR3 chondrodysplasias ranging from lethal forms to the milder phenotype seen in hypochondroplasia (Hch). The p.N540K mutation in the FGFR3 gene occurs in ∼70% of individuals with Hch, and nearly 30% of individuals with the Hch phenotype have no mutations in the FGFR3, which suggests genetic heterogeneity. The identification of a severe case of Hch associated with the typical mutation c.1620C > A and the occurrence of a c.1150T > C change that resulted in a p.F384L in exon 10, together with the suspicion that this second change could be a modulator of the phenotype, prompted us to investigate this hypothesis in a cohort of patients. An analysis of 48 patients with FGFR3 chondrodysplasia phenotypes and 330 healthy (control) individuals revealed no significant difference in the frequency of the C allele at the c.1150 position (p = 0.34). One patient carrying the combination `pathogenic mutation plus the allelic variant c.1150T > C' had a typical achondroplasia (Ach) phenotype. In addition, three other patients with atypical phenotypes showed no association with the allelic variant. Together, these results do not support the hypothesis of a modulatory role for the c.1150T > C change in the FGFR3 gene.

Molecular analysis of holoprosencephaly in South America.

Holoprosencephaly (HPE) is a spectrum of brain and facial malformations primarily reflecting genetic factors, such as chromosomal abnormalities and gene mutations. Here, we present a clinical and molecular analysis of 195 probands with HPE or microforms; approximately 72% of the patients were derived from the Latin American Collaborative Study of Congenital Malformations (ECLAMC), and 82% of the patients were newborns. Alobar HPE was the predominant brain defect in almost all facial defect categories, except for patients without oral cleft and median or lateral oral clefts. Ethmocephaly, cebocephaly, and premaxillary agenesis were primarily observed among female patients. Premaxillary agenesis occurred in six of the nine diabetic mothers. Recurrence of HPE or microform was approximately 19%. The frequency of microdeletions, detected using Multiplex Ligation-dependant Probe Amplification (MLPA) was 17% in patients with a normal karyotype. Cytogenetics or QF-PCR analyses revealed chromosomal anomalies in 27% of the probands. Mutational analyses in genes SHH, ZIC2, SIX3 and TGIF were performed in 119 patients, revealing eight mutations in SHH, two mutations in SIX3 and two mutations in ZIC2. Thus, a detailed clinical description of new HPE cases with identified genetic anomalies might establish genotypic and phenotypic correlations and contribute to the development of additional strategies for the analysis of new cases.

Downregulation of 14q32 microRNAs in Primary Human Desmoplastic Medulloblastoma.

Medulloblastoma (MB) is one of the most common pediatric cancers, likely originating from abnormal development of cerebellar progenitor neurons. MicroRNA (miRNA) has been shown to play an important role in the development of the central nervous system. Microarray analysis was used to investigate miRNA expression in desmoplastic MB from patients diagnosed at a young age (1 or 2 years old). Normal fetal or newborn cerebellum was used as control. A total of 84 differentially expressed miRNAs (64 downregulated and 20 upregulated) were found. Most downregulated miRNAs (32/64) were found to belong to the cluster of miRNAs at the 14q32 locus, suggesting that this miRNA locus is regulated as a module in MB. Possible mechanisms of 14q32 miRNAs downregulation were investigated by the analysis of publicly available gene expression data sets. First, expression of estrogen-related receptor-γ (ESRRG), a reported positive transcriptional regulator of some 14q32 miRNAs, was found downregulated in desmoplastic MB. Second, expression of the parentally imprinted gene MEG3 was lower in MB in comparison to normal cerebellum, suggesting a possible epigenetic silencing of the 14q32 locus. miR-129-5p (11p11.2/7q32.1), miR-206 (6p12.2), and miR-323-3p (14q32.2), were chosen for functional studies in DAOY cells. Overexpression of miR-129-5p using mimics decreased DAOY proliferation. No effect was found with miR-206 or miR-323 mimics.

Five cases of supernumerary small ring chromosomes 1: heterogeneity and genotype-phenotype correlation.

Genetic counselling of patients with small supernumerary ring chromosomes (sSRCs) can be difficult, especially in prenatal testing, due to the complexity in establishing a karyotype-phenotype correlation. In fact, it has been estimated that about 10% of extra ring(1) chromosomes are associated with an unremarkable phenotype. We report on five new cases of extra ring chromosomes(1) manifesting different clinical outcome. One case was familial, segregating from a mother with mosaic karyotype, while the others were de novo. Ring chromosomes were characterised by FISH. In three subjects the involvement of the same euchromatic 1p region was demonstrated. Present observations corroborate previous results and provide some insight into the identification of the harmless ring(1) structures.

Fraser and Ablepharon macrostomia phenotypes: concurrence in one family and association with mutated FRAS1.

To date, Fraser syndrome (FS) and Ablepharon macrostomia syndrome (AMS) have been considered distinct disorders, but they share strikingly similar patterns of congenital abnormalities, specifically craniofacial anomalies. While recent research has led to the identification of the genes FRAS1 and FREM2 as the cause of FS, the genetic basis of AMS continues to be enigmatic. We report on the concurrence of AMS-like and Fraser phenotypes in a Brazilian family. Both affected sibs were homozygous for a novel splice site mutation in the FRAS1 gene. Extensive studies on mRNA expression indicated that this mutation most likely leads to loss of function as most previously reported FRAS1 mutations associated with FS. We conclude that a phenotype resembling AMS is a rare clinical expression of FS with no obvious genotype-phenotype correlation. However, the molecular basis of "true" AMS which has been reported as a sporadic disorder in all cases but one, and so far with no relation to FS, is probably different and still needs to be further investigated.

[Importance of the clinical genetics evaluation on hydrocephalus]. / Importância da avaliação genético-clínica na hidrocefalia.

The aim of this study was to characterize the possibility of genetic etiology in a group of individuals with congenital hydrocephalus in which the etiology was indeterminate and to confirm that earlier diagnosed. The casuistry was composed by 16 individuals with congenital hydrocephalus. Investigation protocol included anamnesis, familial investigation, physical examination, computerized tomography or magnetic resonance image of head, vertebral column X-ray, karyotype and dysmorphological study. Results were analyzed in two groups. In Group I (3M:9F) was composed by hydrocephalus associated with unspecific signs. Group II (7 males) had findings of epectrum of L1 disease. Genetic counseling could be offered in 11 cases. These results demonstrate the great etiological heterogeneity of congenital hydrocephalus and reinforce the importance of dysmphology evaluation as an important complementary investigation.

Scalp lesions in Turner syndrome: a result of lymphoedema?

Lymphoedema and skin naevi are common in children with Turner syndrome (TS). Lymphoedema in the early stages of fetal life is thought to cause several of the phenotypic characteristics in patients with TS such as nuchal folds and pterygium colli. We present two patients with TS who have unusual lesions on the scalp. The first patient had an oval circumscribed lesion. Two biopsies were obtained from the lesion. Increased numbers of collagen fibres were seen in the reticular dermis suggesting the diagnosis of connective tissue naevus. The second patient presented with an area with skin folds on the scalp, similar to cutis verticis gyrata. Although unusual in TS, both lesions could be considered as resolving stages of lymphoedema. We suggest that karyotyping should be performed in cases of female infants presenting with similar lesions.

Importância da avaliação genético-clínica na hidrocefalia / Importance of the clinical genetics evaluation on hydrocephalus

Os objetivos deste estudo foram caracterizar a presença de possíveis quadros de etiologia genética entre portadores de hidrocefalia congênita de etiologia não anteriormente esclarecida e confirmar aqueles com etiologia identificada previamente. A casuística compôs-se de 16 pacientes portadores de hidrocefalia congênita. O protocolo de investigação incluiu anamnese, investigação de história familial, exame clínico-dismorfológico, tomografia computadorizada ou ressonância magnética de sistema nervoso central, radiografia vertebral simples, cariótipo e estudo dismorfológico. Para análise dos resultados, a casuística foi dividida em dois grupos. O Grupo I (3M:6F) caracterizado por indivíduos com hidrocefalia e sinais clínicos inespecíficos; o Grupo II (7M), em que os indivíduos apresentavam hidrocefalia congênita e sinais sugestivos do espectro da doença L1. Orientação genética específica foi possível em 11 casos. Os resultados demonstram a heterogeneidade etiológica envolvida na hidrocefalia, evidenciando a necessidade de avaliação clínico-dismorfológica como instrumento complementar na investigação dessa condição clínica.