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Poikiloderma with Neutropenia (PN), Clericuzio-Type (OMIM #604173) is characterized by poikiloderma, chronic neutropenia, recurrent sinopulmonary infections, bronchiectasis, and nail dystrophy. First described by Clericuzio in 1991 in 14 patients of Navajo descent, it has since also been described in non-Navajo patients. C16orf57 has recently been identified as a causative gene in PN. The purpose of our study was to describe a spectrum of C16orf57 mutations in a cohort of PN patients including five patients of Athabaskan (Navajo and Apache) ancestry. Eleven patients from eight kindreds were enrolled in an IRB-approved study at Baylor College of Medicine. Five patients were of Athabaskan ancestry. PCR amplification and sequencing of the entire coding region of the C16orf57 gene was performed on genomic DNA. We identified biallelic C16orf57 mutations in all 11 PN patients in our cohort. The seven new deleterious mutations consisted of deletion (2), nonsense (3), and splice site (2) mutations. The patients of Athabaskan ancestry all had a common deletion mutation (c.496delA) which was not found in the six non-Athabaskan patients. Mutations in the C16orf57 gene have been identified thus far in all patients studied with a clinical diagnosis of PN. We have identified seven new mutations in C16orf57 in PN patients. One of these is present in all patients of Athabaskan descent, suggesting that c.496delA represents the PN-causative mutation in this subpopulation., (Copyright © 2010 Wiley-Liss, Inc.)

We describe nine previously unreported individuals from six families who have homozygous mutations of HOXA1 and either the Bosley-Salih-Alorainy syndrome (BSAS) or the Athabascan brainstem dysgenesis syndrome (ABDS). Congenital heart disease was present in four BSAS patients, two of whom had neither deafness nor horizontal gaze restriction, thus raising the possibility that cardiovascular malformations might be a clinically isolated, or relatively isolated, manifestation of homozygous HOXA1 mutations. Two ABDS probands had relatively mild mental retardation. These individuals blur the clinical distinctions between the BSAS and ABDS HOXA1 variants and broaden the phenotype and genotype of the homozygous HOXA1 mutation clinical spectrum., (2008 Wiley-Liss, Inc.)

We report a new disorder with diverse neurological problems resulting from abnormal brainstem function. Consistent features of this disorder, which we propose should be called the Atabascan brainstem dysgenesis syndrome, include horizontal gaze palsy, sensorineural deafness, central hypoventilation, and developmental delay. Other features seen in some patients include swallowing dysfunction, vocal cord paralysis, facial paresis, seizures, and cardiac outflow tract anomalies. All affected children described are of Athabascan Indian heritage, with eight children from the Navajo tribe and two patients who are of Apache background. The disorder can be distinguished from the Moebius syndrome by the pattern of central nervous system findings, especially the sensorineural deafness, horizontal gaze palsy, and central hypoventilation. Recognition of children with some features of Athabascan brainstem dysgenesis syndrome should prompt investigation for other related abnormalities. Published 2003 Wiley-Liss, Inc.