Development of the human nervous system involves complex interactions between fundamental cellular processes and requires a multitude of genes, many of which remain to be associated with human disease. We applied whole exome sequencing to 128 mostly consanguineous families with neurogenetic disorders that often included brain malformations. Rare variant analyses for both single nucleotide variant (SNV) and copy number variant (CNV) alleles allowed for identification of 45 novel variants in 43 known disease genes, 41 candidate genes, and CNVs in 10 families, with an overall potential molecular cause identified in >85% of families studied. Among the candidate genes identified, we found PRUNE, VARS, and DHX37 in multiple families, and homozygous loss of function variants in AGBL2, SLC18A2, SMARCA1, UBQLN1, and CPLX1. Neuroimaging and in silico analysis of functional and expression proximity between candidate and known disease genes allowed for further understanding of genetic networks underlying specific types of brain malformations.

Genetic control of craniofacial morphogenesis requires a complex interaction of numerous genes encoding factors essential for patterning and differentiation. We present two Turkish families with a new autosomal recessive frontofacial dysostosis syndrome characterized by total alopecia, a large skull defect, coronal craniosynostosis, hypertelorism, severely depressed nasal bridge and ridge, bifid nasal tip, hypogonadism, callosal body agenesis and mental retardation. Using homozygosity mapping, we mapped the entity to chromosome 11p11.2-q12.3 and subsequently identified a homozygous c.793C-->T nonsense mutation in the human ortholog of the mouse aristaless-like homeobox 4 (ALX4) gene. This mutation is predicted to result in a premature stop codon (p.R265X) of ALX4 truncating 146 amino acids of the protein including a part of the highly conserved homeodomain and the C-terminal paired tail domain. Although the RNA is stable and not degraded by nonsense-mediated RNA decay, the mutant protein is likely to be non-functional. In a skin biopsy of an affected individual, we observed a hypomorphic interfollicular epidermis with reduced suprabasal layers associated with impaired interfollicular epidermal differentiation. Hair follicle-like structures were present but showed altered differentiation. Our data indicate that ALX4 plays a critical role both in craniofacial development as in skin and hair follicle development in human.

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The CH, CRF, and Goldman-correlated IOP were significantly lower in the Marfan syndrome eyes with ectopia lentis than in the Marfan syndrome eyes without ectopia lentis.

Alström Syndrome is an autosomal recessive disease characterized by multiple organ involvement, including neurosensory vision and hearing loss, childhood obesity, diabetes mellitus, cardiomyopathy, hypogonadism, and pulmonary, hepatic, renal failure, and systemic fibrosis. Alström Syndrome is caused by mutations in ALMS1, and ALMS1 protein is thought to play a role in microtubule organization, intraflagellar transport, endosome recycling and cell cycle regulation. Here, we report extensive phenotypic and genetic analysis of a large cohort of Turkish patients with Alström Syndrome. We evaluated 61 Turkish patients, including 11 previously reported, for both clinical spectrum and mutations in ALMS1. To reveal the molecular diagnosis of the patients, there different approaches were used in combination, a cohort of patients were screened by the gene array to detect the common mutations in ALMS1 gene, then in patients having any of common ALMS1 mutations were subjected to direct DNA sequencing or next generation sequencing for the screening of mutations in all coding regions of the gene. In total, 20 distinct disease-causing nucleotide changes in ALMS1 have been identified, 8 of which are novel, thereby increasing the reported ALMS1 mutations by 6% (8/120). Five disease-causing variants were identified in more than one kindred, but most alleles were unique to each single patient and identified only once (16/20). So far, 16 mutations identified were specific to the Turkish population, and four have also been reported in other ethnicities. Additionally, 49 variants of uncertain pathogenicity were noted, and four of these were very rare and probably or likely deleterious according to in silico mutation prediction analyses. Alström Syndrome has a relatively high incidence in Turkey and the present study shows that the ALMS1 mutations are largely heterogeneous; thus, these data from a particular population may provide a unique source for the identification of additional mutations underlying Alström Syndrome and contribute to genotype-phenotype correlation studies.