Background: Autosomal recessive congenital ichthyosis (ARCI) is a heterogeneous group of skin disorders. Several mutant genes have been identified in ARCI, but the association between genotype and phenotype is poorly understood. Methods: To investigate genotype-phenotype correlations in ARCI, we selected 27 patients from 18 families with specific ultrastructural features of the epidermis. The characteristic findings using electron microscopy (EM) were abnormal lamellar bodies and elongated membranes in the stratum granulosum, classified as ARCI EM type III. DNA samples from a subset of affected individuals were screened for homozygous genomic regions, and a candidate gene region was identified on chromosome 5q33. The region coincides with the ichthyin gene, previously reported as mutated in ARCI. Results: Mutation screening of ichthyin revealed missense or splice-site mutations in affected members from 16 of 18 (89%) families with characteristics of ARCI EM type III. In a control group of 18 patients with ARCI without EM findings consistent with type III, we identified one patient homozygous for a missense mutation in ichthyin. Discussion: Our findings indicate a strong association between ultrastructural abnormalities in the granular layer of epidermis and ichthyin mutations. The results also suggest that EM provides a tool for specific diagnosis in a genetically homogenous subgroup of patients with ARCI.

KLICK syndrome is a rare autosomal-recessive skin disorder characterized by palmoplantar keratoderma, linear hyperkeratotic papules, and ichthyosiform scaling. In order to establish the genetic cause of this disorder, we collected DNA samples from eight European probands. Using high-density genome-wide SNP analysis, we identified a 1.5 Mb homozygous candidate region on chromosome 13q. Sequence analysis of the ten annotated genes in the candidate region revealed homozygosity for a single-nucleotide deletion at position c.-95 in the proteasome maturation protein (POMP) gene, in all probands. The deletion is included in POMP transcript variants with long 5' untranslated regions (UTRs) and was associated with a marked increase of these transcript variants in keratinocytes from KLICK patients. POMP is a ubiquitously expressed protein and functions as a chaperone for proteasome maturation. Immunohistochemical analysis of skin biopsies from KLICK patients revealed an altered epidermal distribution of POMP, the proteasome subunit proteins alpha 7 and beta 5, and the ER stress marker CHOP. Our results suggest that KLICK syndrome is caused by a single-nucleotide deletion in the 5' UTR of POMP resulting in altered distribution of POMP in epidermis and a perturbed formation of the outermost layers of the skin. These findings imply that the proteasome has a prominent role in the terminal differentiation of human epidermis.

Aplasia of lacrimal and salivary glands (ALSG) is an autosomal dominant congenital anomaly characterized by aplasia, atresia or hypoplasia of the lacrimal and salivary systems. Affected individuals present with irritable eyes and dryness of the mouth with variable expressivity. Mutations in FGF10 were recently described in ALSG and in lacrimo-auriculo-dento-digital (LADD) syndrome which are overlapping clinical entities. We present here two families with ALSG associated with missense mutations (R80S and G138E, respectively) affecting highly conserved residues in FGF10. The clinical features of these patients further broaden the knowledge of FGF10-related phenotypes.

In men, large tonsils, a high tongue, and a wide uvula were independent factors associated with an apnea-hypopnea index of >15. In women, large tonsils and mandibular retrognathia were independent factors associated with an apnea-hypopnea index of >15. The positive predictive values for upper airway abnormalities ranged between 0.20 and 0.25 in men and between 0.09 and 0.15 in women.

Background Autoimmune disease is one of the leading causes of morbidity and mortality worldwide. In Addison's disease, the adrenal glands are targeted by destructive autoimmunity. Despite being the most common cause of primary adrenal failure, little is known about its aetiology. Methods To understand the genetic background of Addison's disease, we utilized the extensively characterized patients of the Swedish Addison Registry. We developed an extended exome capture array comprising a selected set of 1853 genes and their potential regulatory elements, for the purpose of sequencing 479 patients with Addison's disease and 1394 controls. Results We identified BACH2 (rs62408233‐A, OR = 2.01 (1.71–2.37), P = 1.66 × 10−15, MAF 0.46/0.29 in cases/controls) as a novel gene associated with Addison's disease development. We also confirmed the previously known associations with the HLA complex. Conclusion Whilst BACH2 has been previously reported to associate with organ‐specific autoimmune diseases co‐inherited with Addison's disease, we have identified BACH2 as a major risk locus in Addison's disease, independent of concomitant autoimmune diseases. Our results may enable future research towards preventive disease treatment.