Short rib-polydactyly syndrome: more evidence of a continuous spectrum

We report a fetus with radiological features of the four established types of short rib-polydactyly syndrome (SRPS). The phenotype of this fetus supports the previously suggested hypothesis that the different subtypes of the short rib and polydactyly syndrome are not single entities, but rather, part of a continuous spectrum with variable expressivity.     

Complex consanguinity associated with short rib-polydactyly syndrome III and congenital infection-like syndrome: a diagnostic problem in dysmorphic syndromes

Short rib-polydactyly syndromes (SRPS) are a heterogeneous group of recessively inherited lethal skeletal dysplasias. Four types have been recognised. However, overlap in the clinical and radiological features of the four types has led to difficulties in distinguishing between them. The congenital infection-like syndrome is an autosomal recessive syndrome characterised by mental retardation, microcephaly, seizures, and intracranial calcifications. We report a complex consanguineous family of Baluchi origin in whom short rib-polydactyly type III and congenital infection-like syndrome are segregating. Four children inherited SRPS III, one inherited congenital infection-like syndrome, and one inherited both. Although the radiological features in all the children with SRPS in this report were typical of type III, there was overlap in the clinical features with the other types of SRP syndromes. Furthermore, the child who inherited both SRPS III and congenital infection-like syndrome had CNS malformations in addition to periventricular calcification. CNS malformations have been described in SRPS types II and IV but not type III. This report further highlights the overlap between the different types of SRP syndrome. Moreover, it draws attention to the importance of considering the possibility of two recessive syndromes in the same child in complex consanguineous families when features overlap two syndromes.     

Auriculo-condylar syndrome: further evidence for a new disorder.

We report on a patient born to normal and nonconsanguineous parents and presenting with strikingly malformed ears, abnormalities of the condyle of the mandible, micrognathia, small mouth, and cleft uvula. The similarity of our patient with those reported previously by Jampol et al. [1998: Am. J. Med. Genet. 75:449-452] led us to suggest that they have the same condition.     

Immunogenic and cell attachment sites of FMDV: further evidence for their location in a single capsid polypeptide.

Chymotrypsin cleaves only one of the four major polypeptides of foot-and-mouth disease virus (FMDV serotype O) in situ. This polypeptide (VP1, mol. wt. 29 X 10(3) was first cleaved into fragments of mol. wt. 20 and 9 X 10(3) and further cleavage could be prevented by the addition of a large excess of bovine serum albumin. The infectivity of the virus particles at this stage was the same as that of the intact virus although the rate of attachment to BHK 21 cells was slower and the immunogenic activity was reduced. If hydrolysis was allowed to continue, VP1 was cleaved into fragments with mol. wt. 18 and less than 9 X 10(3), similar to those obtained with trypsin and the virus particles then had a greatly reduced infectivity and a lower immunogenicity. Treatment of strains from five other serotypes of the virus with the two enzymes cleaved only VP1 in each instance and there was a corresponding loss of infectivity. The results are discussed in relation to the location and biological activity of the virus polypeptides.     

Lethal congenital contracture syndrome: further delineation and genetic aspects.

In a national morphology based study of lethal arthrogryposis between 1979 and 1992, 40 fetuses and infants with lethal congenital contracture syndrome (LCCS, McKusick 253310) were found in Finland. The incidence of LCCS in Finland was 1:19,000 births. There were 20 affected males and 20 affected females in 26 families. In 16 cases the pregnancy was terminated after the prenatal diagnosis of total akinesia and fetal hydrops on ultrasound. There were 19 stillborn infants and five were born showing signs of life, but died within one hour. The segregation analyses yielded 0.45 affected by the "singles" method and 0.34 by the "sib" method. The birthplaces of the grandparents were located in the sparsely populated north east of Finland. This finding supports the existence of an autosomal recessive LCCS gene in Finland, particularly in the north eastern part.     

Acrometageria: a spectrum of "premature aging" syndromes.

A child with manifestations of acrogeria and metageria, two "premature aging" syndromes, is presented. Because of his indistinct phenotype and because the question has been previously raised as to whether these conditions are separate, we propose the designation of acrometageria to describe this phenotypic continuum. As there is much in common clinically between acrometageria and the syndrome of type III procollagen deficiency (Ehlers-Danlos type IV), it might be presumed that a similar pathogenesis for acrometageria exists. This possibility has been tested previously, without demonstrating specific quantitative or qualitative deficits, but with some indirect evidence that collagen metabolism is deranged in these patients. One such crude indicator is the elevation of urinary hyaluronic acid levels, demonstrated in our patient and also observed in the phenotypically distinct Werner and Hutchinson-Gilford premature aging syndromes. On one hand, it could be argued that this supports the concept that premature aging syndromes exist as a biological continuum. On the other hand, it is equally valid to argue that syndromes of premature aging are so described merely because they include recognizable changes of normal aging and that the demonstration of an underlying mutation in a collagen gene, for example, invalidates their study as models of accelerated normal aging.     

Micro and Martsolf syndromes in 34 new patients: Refining the phenotypic spectrum and further molecular insights

Micro and Martsolf syndromes are rare clinically and genetically overlapping disorders caused by mutations in RAB3GAP1, RAB3GAP2, RAB18 and TBC1D20 genes. We describe 34 new patients, 27 with Micro and seven with Martsolf. Patients presented with the characteristic clinical manifestations of the two syndromes, including postnatal microcephaly, congenital cataracts, microphthalmia, optic atrophy, spasticity and intellectual disability. Brain imaging showed in the majority of cases polymicrogyria, thin corpus callosum, cortical atrophy, and white matter dysmyelination. Unusual additional findings were pectus excavatum (four patients), pectus carinatum (three patients), congenital heart disease (three patients) and bilateral calcification in basal ganglia (one patient). Mutational analysis of RAB3GAP1 and RAB3GAP2 revealed 21 mutations, including 14 novel variants. RAB3GAP1 mutations were identified in 22 patients with Micro, including a deletion of the entire gene in one patient. On the other hand, RAB3GAP2 mutations were identified in two patients with Micro and all Martsolf patients. Moreover, exome sequencing unraveled a TBC1D20 mutation in an additional family with Micro syndrome. Our results expand the phenotypic and mutational spectrum associated with Micro and Martsolf syndromes. Due to the overlapped severities and genetic basis of both syndromes, we suggest to be comprehended as one entity “Micro/Martsolf spectrum” or “RAB18 deficiency.”     

Insulitis as a consequence of immune dysregulation: further evidence.

Lymphocytic infiltrations in pancreatic islets (insulitis) have been shown previously to occur in mice with spontaneous or experimentally induced immune disorders. We now have studied which type of immune dysregulation leads to insulitis. Immune disorders were induced by treatment with cyclophosphamide (Cy) or phenytoin and by graft versus host reactions (GVHR) across minor or major histocompatibility barriers. Histological analysis of immune disturbed animals revealed insulitis after phenytoin treatment and as a consequence of GVHR. Insulitis during GVHR is only observed in certain mouse strain combinations. Treatment with Cy in a large dose range does not lead to lymphocytic infiltration of pancreatic islets. It is concluded that cellular immunity to islet cells can occur spontaneously during certain types of immune dysregulation. Since phenytoin treatment and GVHR stimulate lymphocytes reactive with major histocompatibility antigens, such structures may also be part of target antigens on islet cells.     

Liposomes in immunology: further evidence for the adjuvant activity of liposomes.

The immune response to HSA-phosphatidylcholine complexes administered to rabbits was not markedly enhanced when compared with the response to unmodified HSA. It was found in earlier work that HSA entrapped in liposomes (mainly composed of phosphatidylcholine) evoked a strong immune response under conditions where no response was detected to free HSA. The present results exclude the possibility that HSA-phosphatidylcholine complexes which may arise from liposome-encapsulated HSA may be responsible for the adjuvant activity of the liposome. The adjuvant activity of liposomes could also be established after administration of a liposome-associated strong antigen (BGG).     

Exclusion of PTPN11 mutations in Costello syndrome: further evidence for distinct genetic etiologies for Noonan,cardio-facio-cutaneous and Costello syndromes

Costello syndrome (CS) is a rare, multiple congenital anomaly syndrome with characteristic dysmorphic features, cardiac anomalies and a tendency to develop certain cancers. Phenotypically there is some overlap with other genetic disorders, notably cardio-facio-cutaneous (CFC) syndrome and Noonan syndrome (NS), suggesting that these syndromes may be allelic. We recently identified PTPN11, which encodes the non-receptor protein tyrosine phosphatase, SHP-2, as a major NS disease gene. In this report, we screened a cohort of 27 patients, with the clinical diagnosis of CS, for PTPN11 mutations using denaturing high performance liquid chromatography analysis. No mutations of the PTPN11 gene were found in the CS patients. Common polymorphisms in introns 6 and 7 and exon 8 were identified in four individuals. With our previous exclusion of PTPN11 mutations in CFC syndrome, these data suggest distinct genetic etiologies for Noonan, CFC and Costello syndromes.     

Variant of iduronidase deficient mucopolysaccharidoses: further evidence for genetic heterogeneity.

An alpha-L-iduronidase deficiency syndrome has been described in adult male twins, which was phenotypically distinct from that of the Hurler and Scheie syndromes or the chondroitinsulphaturias. Multiple dysostosis and stiff joints were present without cloudy corneae, cardiac involvement and mental or physical retardation. This clinical phenotype appeared to be a newly recognized allelic mutation at the iduronidase locus but does not exclude a non-allelic mutation coding for a subunit of the iduronidase molecule.     

Replication of the pseudorabies virus in cultured pancreatic islet cells: further evidence of their paraneuronal nature.

Pancreatic B cells are known to be damaged by a wide range of viruses, causing diabetes. Though these viruses belong to different taxonomic groups, their single shared characteristic is neurotropism. In the present study, pseudorabies viral infection was modelled on fetal porcine islets cultivated in vitro. It was demonstrated that the endocrine cells of the pancreas, especially B cells, were infected in vitro and so served as a medium for the replication of the virus. All stages of the morphogenesis of the virus were observed ultrastructurally within the cells. The exocrine cells located close to the endocrine ones were free from attachment and invasion of the virus. The potential of the pseudorabies virus to develop within pancreatic endocrine cells is regarded as evidence of the paraneuronal nature of these cells.     

Autism spectrum disorders: The quest for genetic syndromes

Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental disabilities with various etiologies, but with a heritability estimate of more than 90%. Although the strong correlation between autism and genetic factors has been long established, the exact genetic background of ASD remains unclear. A number of genetic syndromes manifest ASD at higher than expected frequencies compared to the general population. These syndromes account for more than 10% of all ASD cases and include tuberous sclerosis, fragile X, Down, neurofibromatosis, Angelman, Prader–Willi, Williams, Duchenne, etc. Clinicians are increasingly required to recognize genetic disorders in individuals with ASD, in terms of providing proper care and prognosis to the patient, as well as genetic counseling to the family. Vice versa, it is equally essential to identify ASD in patients with genetic syndromes, in order to ensure correct management and appropriate educational placement. During investigation of genetic syndromes, a number of issues emerge: impact of intellectual disability in ASD diagnoses, identification of autistic subphenotypes and differences from idiopathic autism, validity of assessment tools designed for idiopathic autism, possible mechanisms for the association with ASD, etc. Findings from the study of genetic syndromes are incorporated into the ongoing research on autism etiology and pathogenesis; different syndromes converge upon common biological backgrounds (such as disrupted molecular pathways and brain circuitries), which probably account for their comorbidity with autism. This review paper critically examines the prevalence and characteristics of the main genetic syndromes, as well as the possible mechanisms for their association with ASD. © 2013 Wiley Periodicals, Inc. © 2013 Wiley Periodicals, Inc.     

Septo-optic dysplasia and amniotic bands: further evidence for a vascular pathogenesis

Septo-optic dysplasia (SOD) is a heterogeneous disorder. While most cases represent an isolated defect, SOD has also been seen in association with mutations in single genes, as a part of multiple congenital anomaly syndromes and with exposure to various teratogens. We report a boy with features of SOD who also has limb defects suggestive of amniotic bands. This case, in addition to others in the literature, provides evidence for a vascular pathogenesis of SOD in some individuals. This hypothesis is also supported by the sporadic occurrence of SOD and its association with decreased maternal age, vascular teratogens, and neuropathologic findings suggestive of vascular insults.     

Hirschsprung''s disease and Ondine''s curse: further evidence for a distinct syndrome

Although Hirschsprung's disease is a relatively common congenital malformation, with an estimated incidence of about 1:5000, Primary Central Hypoventilation Syndrome (Ondine's curse) is exceedingly rare, with about 50 reported cases. We describe a patient with total colonic aganglionosis occurring together with failure of automatic control of respiration, specific facial dysmorphology and characteristic CT scan changes to substantiate further the syndromic nature of this association.