Copy-number mutations on chromosome 17q24.2-q24.3 in congenital generalized hypertrichosis terminalis with or without gingival hyperplasia.

Congenital generalized hypertrichosis terminalis (CGHT) is a rare condition characterized by universal excessive growth of pigmented terminal hairs and often accompanied with gingival hyperplasia. In the present study, we describe three Han Chinese families with autosomal-dominant CGHT and a sporadic case with extreme CGHT and gingival hyperplasia. We first did a genome-wide linkage scan in a large four-generation family. Our parametric multipoint linkage analysis revealed a genetic locus for CGHT on chromosome 17q24.2-q24.3. Further two-point linkage and haplotyping with microsatellite markers from the same chromosome region confirmed the genetic mapping and showed in all the families a microdeletion within the critical region that was present in all affected individuals but not in unaffected family members. We then carried out copy-number analysis with the Affymetrix Genome-Wide Human SNP Array 6.0 and detected genomic microdeletions of different sizes and with different breakpoints in the three families. We validated these microdeletions by real-time quantitative PCR and confirmed their perfect cosegregation with the disease phenotype in the three families. In the sporadic case, however, we found a de novo microduplication. Two-color interphase FISH analysis demonstrated that the duplication was inverted. These copy-number variations (CNVs) shared a common genomic region in which CNV is not reported in the public database and was not detected in our 434 unrelated Han Chinese normal controls. Thus, pathogenic copy-number mutations on 17q24.2-q24.3 are responsible for CGHT with or without gingival hyperplasia. Our work identifies CGHT as a genomic disorder.

PHACE syndrome: MRI of intracerebral vascular anomalies and clinical findings in a series of 12 patients.

BACKGROUND: PHACE (posterior fossa defects, haemangioma, arterial anomalies, coarctation of the aorta and cardiac defects, eye abnormalities) syndrome describes a constellation of abnormalities that can occur in association with segmental craniofacial infantile haemangioma. OBJECTIVE: To report the spectrum of clinical and imaging abnormalities seen in a cohort of children. MATERIALS AND METHODS: A retrospective review of the clinical and imaging records of all patients diagnosed with PHACE syndrome between 1998 and 2009 was performed. Information sought included patient demographics, craniofacial segments involved, imaging findings and other extracutaneous abnormalities. RESULTS: Twelve patients were diagnosed with PHACE syndrome over 11 years. All patients had a segmental craniofacial haemangioma. Involved facial segments, in order of frequency, were frontotemporal (12), maxillary (8), mandibular (5) and frontonasal (1). The most common extracutaneous abnormalities were neurovascular anomalies (10), with many patients having multiple anomalies. The spectrum of arterial anomalies ranged from hypoplasia (9) to ectasia (3), anomalous origin/course (2) and persistent fetal anastomosis (2). Other anomalies found included cardiac anomalies (3), coarctation of the aorta (2), posterior fossa malformations (1) and sternal region anomalies (1). CONCLUSION: Intracranial anomalies are the most common extracutaneous feature of PHACE syndrome. The contribution of the radiologist in the recognition of such anomalies is important for the diagnosis of PHACE syndrome.

Towards a unified classification of the ectodermal dysplasias: opportunities outweigh challenges.

The ectodermal dysplasias include a complex and highly diverse group of heritable disorders that share in common developmental abnormalities of ectodermal derivatives. The broader definition of ectodermal dysplasias (as heritable disorders involving at least two of the ectodermal derivatives nails, teeth, hair, and eccrine sweat glands) encompasses 170-200 conditions. Some conditions included by this definition are relatively common; others are rare and, in some cases, family-specific. Classification of the ectodermal dysplasias has largely been approached by categorizing patterns of clinical findings (phenotypic grouping). In the last 2 decades great progress has been made in understanding the molecular pathogenesis and inter-relatedness of some of these conditions and a new consensus approach to classification that incorporates this new information is needed. A comprehensive and definitive classification of these disorders would be highly valuable for the many stakeholders in ED. As disease-specific molecular treatments are developed, accurate classification will assume greater importance in designing registries to enable rapid identification of those with rare disorders who may wish to participate in clinical trials. Ideally a working classification of such a disparate collection of conditions would have a design and architecture that would facilitate easy accessibility by each of the key stakeholder groups and would encourage enhanced interaction between these parties. Attaining this objective is a major challenge but is achievable. This article reviews the historical-clinical perspective and the impact of recent developments in molecular biology in the field. Reflections are offered as to the future direction of classification systems in these disorders.