Unknown syndrome: ischiadic hypoplasia, renal dysfunction, immunodeficiency, and a pattern of minor congenital anomalies

Genetic syndromic immunodeficiencies with antibody defects

This article reviews the major syndromic immunodeficiencies with significant antibody defects, many of which may require intravenous immunogammaglobulin therapy. The authors define syndromic immunodeficiency as an illness associated with a characteristic group of phenotypic abnormalities or laboratory features that comprise a recognizable syndrome. Many are familial with a defined inheritance pattern. Immunodeficiency may not be a major part of the illness and may not be present in all patients; thus, these conditions differ from primary immunodeficiency syndromes, in which immune abnormalities are a consistent and prominent feature of their disease.

A role for epigenetics in hearing: Establishment and maintenance of auditory specific gene expression patterns

Epigenetics is a large and diverse field encompassing a number of different mechanisms essential to development, DNA stability and gene expression. DNA methylation and histone modifications work individually and in conjunction with each other leading to phenotypic changes. An overwhelming amount of evidence exists demonstrating the essential nature of epigenetics to human biology and pathology. This field has spawned a vast array of knowledge, techniques and pharmaceuticals designed to investigate and manipulate epigenetic phenomena. Despite its centricity to molecular biology, little work has been conducted examining how epigenetics affects hearing. In this review, we discuss both the basic tenets of epigenetics and highlight the most recent advances in this field. We discuss its importance to human development, genomic stability, gene expression, epigenetic modifying agents as well as briefly introduce the expansive field of cancer epigenetics. We then examine the evidence of a role for epigenetics in hearing related processes and hearing loss. The article concludes with a discussion of areas of epigenetic research that could be applied to hearing research.

A novel form of ischio-vertebral syndrome

We report a boy with ischial hypoplasia, vertebral malsegmentation and multiple other skeletal anomalies which do not fit well with any previously-described disorder. The proband's brother and mother were also slightly affected. We review the pertinent literature, discuss the differential diagnosis and suggest that this may be a previously unreported autosomal dominant disorder, with variable penetrance.We believe that the clinical and radiological features of various syndromes with ischial aplasia/hypoplasia and vertebral malsegmentation are not sufficiently different to justify the current separate categories of "ischio-vertebral dysplasia" and "ischio-spinal dysostosis". We suggest that the term "ischio-vertebral syndrome" should be used until identification of genes affecting ischial and axial morphogenesis is completed.

A new and a reclassified ICF patient without mutations in DNMT3B and its interacting proteins SUMO-1 and UBC9

The ICF syndrome (immunodeficiency, centromeric instability, facial anomalies) (OMIM#242860) is a rare autosomal, recessively inherited disorder. Another rare condition, ischiadic hypoplasia, renal dysgenesis, immunodeficiency, and polydactyly (IHRDIP, OMIM#243340), displays features that resemble those of the ICF syndrome. Due to the overlapping symptoms in both syndromes, we asked whether a shared underlying molecular defect exists. Two patients, each with the clinical characteristics of one of these syndromes, were subjected to conventional cytogenetic analysis and the determination of the methylation state of satellite II DNA. We found that both displayed the two hallmark features of the ICF syndrome, namely hypomethylation and centromeric instability of chromosomes 1 and 16. Therefore, we reclassified the patient previously diagnosed with the IHRDIP syndrome as an ICF patient. Since the majority of ICF patients are carriers of mutations in the methytransferase gene DNMT3B, we determined the sequence of its coding, splice site, and putative promoter region and analyzed its transcripts in both patients, without detecting any alterations. Similarly, the coding region of two DNMT3B-interacting proteins, SUMO-1 and UBC9, did not reveal mutations. With this study, the published number of patients that lack mutations in DNMT3B coding region increases to almost 40% of all ICF patients reported. It is, therefore, implied that a significant subset of ICF patients will have a yet unknown, alternative alteration, which may include the involvement of DNMT3B-interacting factors or aberrations of an independent pathway.

Autosomal dominant B-cell immunodeficiency, distal limb anomalies and urogenital malformations (BILU syndrome) - report of a second family

A family with an unusual combination of B-cell immunodeficiency, distal limb abnormalities, genitourinary malformations, and mild dysmorphic features has recently been described. Here, we report a second family with similar features, which also shows autosomal dominant inheritance. In affected individuals from both families, sequence analysis of candidate gene HOXA13 did not identify a mutation, and there was no evidence of a microdeletion involving either HOXA13 or the HOXA cluster as a whole. We further delineate the phenotype of this condition in females and add weight to the observation that this is a true syndromic association.

Syndromic immunodeficiencies: genetic syndromes associated with immune abnormalities

In syndromic immunodeficiencies, clinical features not directly associated with the immune defect are prominent. Patients may present with either infectious complications or extra-immune medical issues. In addition to the immunologic abnormality, a wide range of organ systems may be affected. Patients may present with disturbances in skeletal, neurologic, dermatologic, or gastrointestinal function or development. These conditions can be caused by developmental abnormalities, chromosomal aberrations, metabolic disorders, or teratogens. For a number of these conditions, recent advances have resulted in an enhanced understanding of their genetic basis. The finding of immune deficits in a number of defined syndromes with congenital anomalies suggests that an underlying genetic syndrome should be considered in those patients in whom a significant non-immune feature is present.

Ischiospinal dysostosis with rib gaps and nephroblastomatosis

Rib gaps, vertebral ossification defects, hypoplastic ischial bones and large kidneys were present in a newborn. A renal biopsy showed nephroblastomatosis . The observation links two recently described conditions - 'ischiospinal dysostosis' and 'a new syndrome comprising vertebral anomalies and multicystic kidneys' - and shows that nephroblastomatosis may be a manifestation of ischiospinal dysostosis. Ischiospinal dysostosis with nephroblastomatosis is one of a group of disorders characterized by developmental defects of the axial skeleton. It must be added to the conditions predisposing to Wilms tumor formation.

Immunodeficiency as a component of recognizable syndromes

Immunodeficiency occurs in numerous genetic syndromes. While it is the dominant manifestation in primary immunodeficiencies, immune deficits may also be seen in a variety of other recognizable syndromes. Immunodeficiency has been reported in 64 such conditions, adding to the 45 recognized primary immunodeficiencies. These uncommon syndromes with immune defects can present with: (a) growth deficiency (11 syndromes with disproportionate or proportionate short stature), (b) specific organ system dysfunction (18 with gastrointestinal, dermatologic, or neurologic abnormalities), (c) inborn errors of metabolism (13), (d) miscellaneous anomalies (10), or (e) chromosome anomalies (12). In most of the disorders, only some of the affected patients have immune defects. However, in 27 syndromes, immunodeficiency is a constant finding. We briefly review the clinical manifestations of each syndrome and delineate the specific associated immune defects. In most syndromes, the connection between the immune and other defects is unknown. Recognition of these conditions involving both the immune and other organ systems may facilitate accurate diagnosis and management as well as yield information regarding genes critical for the development of the involved systems.

Two brothers with characteristic facial appearance, severe psychomotor retardation, hypospadias, contractures, and other symptoms: a new recessive syndrome?

We report on two severely mentally retarded male children of consanguineous parents who seem to be affected by an identical syndrome. The main physical anomalies are typical facial stigmata with a broad nasal bridge, a bulbous nose, upward slanting palpebral fissures, microretrognathia, low hair line, and large ears with an incompletely developed upper helix. In addition, both brothers had hypospadias type II, limb contractures, and delayed bone age. One child had a bilateral cleft lip with cleft palate and cryptorchidism, and developed scoliosis during adolescence. The other had bilateral inguinal hernias and strabismus. Chromosome analysis showed a normal karyotype in both. The striking similarity between the brothers, the dissimilarity to other known syndromes, and the parental consanguinity argue in favour of a new, hitherto undescribed, possibly autosomal recessive syndrome.