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.

Identification of Novel and Recurrent RMRP Variants in a Series of Brazilian Patients with Cartilage-Hair Hypoplasia: McKusick Syndrome

Cartilage-hair hypoplasia syndrome (CHH) is an autosomal recessive disorder caused by pathogenic variants of the RMRP gene and characterized by metaphyseal bone dysplasia associated with hypotrichosis, immunodeficiency, and predisposition to malignancy. However, the genotype-phenotype correlation in CHH is not well understood. Here, we report a single country cohort of 23 Brazilian patients with clinical and radiological features consistent with CHH. We found 23 different pathogenic variants in the RMRP gene - 12 novel and 11 previously described in the literature. Interestingly, the most frequent Finnish pathogenic variant related to CHH (g.71A>G) was not found in our cohort. In contrast, more than 50% of the patients carried the rare g.196C>T variant suggesting a possible founder effect in the Brazilian population. In silico analysis showed that pathogenic variants occurred either in the regions conserved in mammalian species or within essential domains for the ribonucleoprotein complex. Pathogenicity prediction studies can improve the understanding of how these variants affect RNA.

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.

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.

Electronic supplementary material

The online version of this article (doi:10.1186/s40001-016-0228-7) contains supplementary material, which is available to authorized users.

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.

High frequency of submicroscopic chromosomal imbalances in patients with syndromic craniosynostosis detected by a combined approach of microsatellite segregation analysis, multiplex ligation-dependent probe amplification and array-based comparative genome hybridisation

We present the first comprehensive study, to our knowledge, on genomic chromosomal analysis in syndromic craniosynostosis. In total, 45 patients with craniosynostotic disorders were screened with a variety of methods including conventional karyotype, microsatellite segregation analysis, subtelomeric multiplex ligation-dependent probe amplification) and whole-genome array-based comparative genome hybridisation. Causative abnormalities were present in 42.2% (19/45) of the samples, and 27.8% (10/36) of the patients with normal conventional karyotype carried submicroscopic imbalances. Our results include a wide variety of imbalances and point to novel chromosomal regions associated with craniosynostosis. The high incidence of pure duplications or trisomies suggests that these are important mechanisms in craniosynostosis, particularly in cases involving the metopic suture.

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.

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.

Molecular screening for microdeletions at 9p22-p24 and 11q23-q24 in a large cohort of patients with trigonocephaly

Trigonocephaly is a rare form of craniosynostosis characterized by the premature closure of the metopic suture. To contribute to a better understanding of the genetic basis of metopic synostosis and in an attempt to restrict the candidate regions related to metopic suture fusion, we studied 76 unrelated patients with syndromic and non-syndromic trigonocephaly. We found a larger proportion of syndromic cases in our population and the ratio of affected male to female was 1.8 : 1 and 5 : 1 in the non-syndromic and syndromic groups, respectively. A microdeletion screening at 9p22-p24 and 11q23-q24 was carried out for all patients and deletions in seven of them were detected, corresponding to 19.4% of all syndromic cases. Deletions were not found in non-syndromic patients. We suggest that a molecular screening for microdeletions at 9p22-p24 and 11q23-q24 should be offered to all syndromic cases with an apparently normal karyotype because it can potentially elucidate the cause of trigonocephaly in this subset of patients. We also suggest that genes on the X-chromosome play a major role in syndromic trigonocephaly.

[Importance of the clinical genetics evaluation on hydrocephalus]

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.

Prenatal exposure to misoprostol and vascular disruption defects: a case-control study

Prenatal exposure to misoprostol has been associated with Moebius and limb defects. Vascular disruption has been proposed as the mechanism for these teratogenic effects. The present study is a multicenter, case-control study that was designed to compare the frequency of prenatal misoprostol use between mothers of Brazilian children diagnosed with vascular disruption defects and matched control mothers of children diagnosed with other types of defects. A total of 93 cases and 279 controls were recruited in eight participating centers. Prenatal exposure was identified in 32 infants diagnosed with vascular disruption defects (34.4%) compared with only 12 (4.3%) in the control group (P<0.0000001). Our data suggest that prenatal exposure to misoprostol is associated to the occurrence of vascular disruption defects in the newborns.

High mutation detection rate in TCOF1 among Treacher Collins syndrome patients reveals clustering of mutations and 16 novel pathogenic changes

Twenty-eight families with a clinical diagnosis of Treacher Collins syndrome were screened for mutations in the 25 coding exons of TCOF1 and their adjacent splice junctions through SSCP and direct sequencing. Pathogenic mutations were detected in 26 patients, yielding the highest detection rate reported so far for this disease (93%) and bringing the number of known disease-causing mutations from 35 to 51. This is the first report to describe clustering of pathogenic mutations. Thirteen novel polymorphic alterations were characterized, confirming previous reports that TCOF1 has an unusually high rate of single-nucleotide polymorphisms (SNPs) within its coding region. We suggest a possible different mechanism leading to TCS or genetic heterogeneity for this condition, as we identified two families with no apparent pathogenic mutation in the gene. Furthermore, our data confirm the absence of genotype-phenotype correlation and reinforce that the apparent anticipation often observed in TCS families is due to ascertainment bias.

Dandy-Walker malformation with postaxial polydactyly: further evidence for autosomal recessive inheritance

We describe an infant with Dandy-Walker malformation and tetramelic postaxial polydactyly type 1A. Parental consanguinity reinforces previous suggestions for autosomal recessive inheritance.

Thalidomide, a current teratogen in South America

Thalidomide, mainly used for the treatment of leprosy, is a current teratogen in South America, and it is reasonable to assume that at present this situation is affecting many births in underdeveloped countries. Moreover, the potential re-marketing of thalidomide for the treatment of a large variety of diseases may extend the problem to the developed world. When the drug is available, the control of its intake during early pregnancy is very difficult since most pregnancies are unintended. The ongoing occurrence of thalidomide embryopathy cases went undetected by the ECLAMC, due to several factors: (1) low populational coverage through this monitoring system; (2) pre-existence of the teratogen with its effects present in both baseline (expected) and monitored (observed) materials; and (3) lack of a defined phenotype to be monitored. Thus, if thalidomide re-enters the market throughout the world, due to the wide range of new applications, occurrence of phocomelia alone might not be sufficient to detect its effects. By a case-reference approach, the ECLAMC registered 34 thalidomide embryopathy cases born in South America after 1965 whose birthplaces correspond to endemic areas for leprosy. Phocomelia was found in five of eleven fully described cases. Thus, phocomelia alone is neither specific nor sufficient to serve as a suitable phenotype to survey the teratogenic effects of thalidomide. Therefore, a thalidomide-like phenotype, defined as any bilateral upper and/or lower limb reduction defect of the preaxial and/or phocomelia types, should be included in the routine surveillance of birth defects in all programmes.

Limb reduction defects in South America

OBJECTIVE

Limb reduction defects were considered as possible indicators of environmental teratogenesis; it was suggested that also invasive prenatal procedures could increase the risk for limb reduction defects. The purpose of this work is to give a baseline frequency for limb reduction defects, using data from a population not exposed to prenatal diagnosis procedures.

DESIGN

Using data collected in the period 1967 to 1992 within the frame of the Latin American Collaborative Study of Congenital Malformations which clinically examined 2,917,074 newborn infants, a total of 1715 with limb reduction defects were found. All cases were classified and analysed in 25 categories. Geographic differences in recorded rates were tested by chi 2 for homogeneity. Secular trends were analysed using chi 2 test for linear trends.

RESULTS

The overall birth prevalence rate of limb reduction defects among liveborn infants was 4.91(per 10,000 births) (3.05 for isolated and 1.85 for associated cases). For stillbirths, the total prevalence was 26.73/10,000 (5.53 for isolated and 21.20 for associated cases). The inclusion of the brachydactylies increased those figures to 5.55/10,000 (3.39 for isolated and 2.16 for associated cases), and 27.42, respectively, (5.53 for isolated and 21.89 for associated cases). When isolated and associated cases were considered together, a geographic heterogeneity was found in pre-axial limb reduction defects; there was also some heterogeneity for amputations. A maternal age effect was found for the isolated hypoplasias. Standardising by maternal age, the overall prevalence of limb reduction in liveborn infants was 5.66 per 10,000 (95% CI = 5.38-5.93). An increasing trend was suggested by the isolated form of distal amputations which involved hands, feet, or digits.

CONCLUSIONS

Our data suggest that clustering limb reduction defects in wide groups as transverse and longitudinal may lead to heterogeneous entities. When a possible association is suspected, it would be preferable to present and analyse data in the most discriminant form available. Due to the maternal age effect, it would be advisable to standardise the rates of transversal limb reduction defects by this variable.

Two cases of Y; autosome translocations: A 45,X male and a clinically trisomy 18 patient

We report on 2 cases of Y; autosome translocations. One is a male with normal external genitalia and 45,X karyotype without evidence of mosaicism or apparent translocation on cytogenetic analysis. In situ hybridization showed that the euchromatic portion of the Y-chromosome is translocated to the chromosome 15. The other case is a clinically trisomy 18 male patient, with modal number of 46, a small metacentric marker with appearance of an i(18p) and cytogenetic and molecular evidence of Y;18 translocation. The occurrence of Y;18 translocation associated with clinical signs of trisomy 18 is reported here for the first time.

Limb anomalies following chorionic villus sampling: a registry based case-control study

Using data from the Italian Multicentric Birth Defect Registry a case-control study was performed to verify if chorionic villus sampling (CVS) was associated with transverse limb defects (TLD), with or without features of oro-mandibular-limb hypogenesis complex (OMLHC), in the exposed offspring. The results show that the risk of TLD and OMLHC is increased following CVS, and is particularly high for CVS performed early in pregnancy, i.e., under 70 days of gestational age. These results, together with a review of other epidemiologic studies, biological data and clinical reports, strongly suggest a causative role of CVS as a risk factor for TLD and indicate that at this stage CVS before 70 days of gestational age should be discouraged as an option for prenatal diagnosis and that all patients wishing to undergo CVS should be informed about the possible risk of the procedure.

Association of microscopic gonadoblastoma and contralateral ovarian fibroadenoma in patients with gonadal dysgenesis and Turner phenotype

A rare case of microscopic gonadoblastoma associated with gonadal fibroadenoma in a patient with gonadal dysgenesis and Turner phenotype is reported. The higher incidence of tumor pathologies in patients with gonadal dysgenesis presenting a Y chromosome in their karyotype is discussed, and the need for judicious microscopic analysis of the gonadal streaks of these patients for the detection of possible incipient tumors is emphasized.

Unknown syndrome: abnormal facies, hypothyroidism, postaxial polydactyly, and severe retardation: a third patient

Young and Simpson in 1987 and Fryns and Moerman in 1988 each reported a case of a new unknown syndrome with hypothyroidism, severe global retardation, and abnormal facies, including microcephaly, blepharophimosis, bulbous nose, thin upper lip, low set ears, and micrognathia. A male infant with a similar pattern of malformations and postaxial polydactyly is reported here.

Tetrasomy 9p caused by idic (9) (pter----q13----pter)

Cytogenetic investigation on a malformed male infant showed an extra chromosome similar to chromosome 9 in all metaphases studied. GTG, CBG, and G-11 staining suggested that the extra chromosome was an abnormal 9, permitting the identification of the chromosome constitution as 47,XY,+idic (9) (pter----q13----pter).