Neonatal Lung Disease Associated with TBX4 Mutations.

Variable lung disease was documented in 2 infants with heterozygous TBX4 mutations; their clinical presentations, pathology, and outcomes were distinct. These findings demonstrate that TBX4 gene mutations are associated with neonatal respiratory failure and highlight the wide spectrum of clinicopathological outcomes that have implications for patient diagnosis and management.

A novel pathogenic variant in OFD1 results in X-linked Joubert syndrome with orofaciodigital features and pituitary aplasia.

Orofaciodigital syndrome type I and X-linked recessive Joubert syndrome are known ciliopathic disorders that are caused by pathogenic variants in OFD1 gene. Endocrine system involvement with these conditions is not well described. We present the first report of a newborn male with a novel hemizygous variant in OFD1 gene c.515T>C, (p.Leu172Pro) resulting in X-linked Joubert syndrome and orofaciodigital features with complete pituitary gland aplasia and subsequent severe hypoplasia of peripheral endocrine glands. This clinical report expands the phenotypic spectrum of endocrine system involvement in OFD1-related disorders and suggests that OFD1 gene may be related to pituitary gland development.

Congenital heart disease and aortic arch variants associated with mutation in PHOX2B.

PURPOSE: Congenital central hypoventilation syndrome (CCHS, OMIM 209880) is a rare autosomal dominant disorder caused by mutation in PHOX2B that manifests as a consequence of abnormal neural crest cell migration during embryogenesis. Unlike other neurocristopathies, however, its impact on the cardiovascular system has not been previously assessed. This study was an effort to characterize the association between congenital heart disease (CHD) and mutations in PHOX2B in patients with CCHS. METHODS: A retrospective review of patients with CCHS in conjunction with functional analysis of PHOX2B mutations associated with CHD was performed. To substantiate functional implications of identified variants, we conducted protein structure analyses and in silico mutagenesis were conducted. RESULTS: The prevalence of CHD among patients with CCHS was significantly greater (30%; p < 0.001) than that of the current estimated prevalence of CHD. The majority of patients had anomalies involving the proximal aortic arch and/or proximal coronary arteries. Variants associated with CHD in this cohort appear to disrupt DNA binding of PHOX2B via alteration of its homeobox domain. CONCLUSION: This is the first report of an association between CHD and mutation in PHOX2B. Results are highly suggestive that alteration or elimination of the homeobox domain conveys significant risk for associated CHD or aortic arch variation.

Congenital lumbar hernia-A feature of diabetic embryopathy?

Congenital lumbar hernia is a rare anomaly consisting of protrusion of abdominal organs or extraperitoneal tissue through a defect in the lateral abdominal wall. The majority of affected patients have additional anomalies in a pattern described as the lumbocostovertebral syndrome. We report four patients born to mothers with poorly controlled diabetes with congenital lumbar hernia. All patients exhibited features of lumbocostovertebral syndrome with lumbar hernia, multiple vertebral segmentation anomalies in the lower thoracic and/or upper lumbar spine, rib anomalies, and unilateral renal agenesis. Additional anomalies present in the patients included preaxial hallucal polydactyly, abnormal situs, and sacral dysgenesis, anomalies known to be associated with diabetic embryopathy. At least 11 other patients have been previously reported with the lumbocostovertebral syndrome in the setting of maternal diabetes. We suggest that congenital lumbar hernia and the lumbocostovertebral syndrome are related to diabetic embryopathy.

Variable phenotype in a novel mutation in PHOX2B.

We evaluated a family with three siblings, two of whom ages 2 years and 19 months, had long segment colonic agangliosis and anisocoria. The mother also had anisocoria. All three affected family members were mildly dysmorphic with a flat facial profile, square appearance to the face, depressed nasal bridge, and anteverted nares. Genetic testing identified a novel heterozygous mutation, c.234C>G, resulting in a premature stop codon in exon 1 of the PHOX2B gene. Screening for neural crest tumors was performed in the siblings and to date has been negative. This family supports a strong association between non polyalanine tract mutations, autonomic dysfunction, and Hirschsprung disease, but suggests mutation outside of the polyalanine tract may not dictate severe phenotype with significant respiratory compromise. A unique finding in this family is the association of congenital heart disease in two of the affected patients. These malformations may be a sporadic isolated finding or the result of environmental factors or a modifying allele. Given the association between congenital heart disease and aberrant neural crest cell development, however, findings are suggestive that congenital heart disease may be a rare feature of PHOX2B mutation which has not been previously reported.