[Central alveolar hypoventilation syndrome and cerebral venous thrombosis: fortuitous association?]

Sinus vein thrombosis as presenting finding in the congenital central hypoventilation syndrome: an insight on the pathophysiology of the association

Congenital central hypoventilation syndrome (CCHS) is an increasingly recognized diagnosis causing central hypoventilation and may be definitively diagnosed by genetic testing. Previous authors reported the association between CCHS and central sinus venous thrombosis (CSVT) and hypothesized that CCHS could be secondary to CSVT. We report a case of CCHS with the typical PHOX2B mutation who also suffered from CSVT. We assume that effects, secondary to CCHS, upon the central venous system may explain the etiological connection between CSVT and CCHS including dysautoregulation, venous stasis or polycythemia. We believe that CCHS should be included in the differential diagnosis of patients with CSVT accompanied by respiratory abnormalities.

Brainstem Anomalies in Two Patients Affected by Congenital Central Hypoventilation Syndrome

Congenital central hypoventilation syndrome (CCHS) is a rare neurocristopathy characterized by absence of automatic control of respiration; decreased sensibility to hypoxia and hypercapnia, mainly during sleep; and autosomal dominant inheritance due to heterozygous polyalanine expansions and frameshift mutations in the PHOX2B gene. Because the CCHS phenotype could hide other neurologic diseases, the American Thoracic Society established that the initial evaluation of suspected CCHS should exclude neuroanatomic impairments as the structural basis of the reduced autonomic system function. In this work, we describe the clinical history of two unrelated patients with hypoventilation during sleep and harboring hypoplasia of the pons and a Chiari I malformation, respectively. In both patients, CCHS was diagnosed by detection of PHOX2B polyalanine expansion, suggesting that the American Thoracic Society diagnostic criteria may be too restrictive. Moreover, to exclude a putative role of PHOX2B in non-CCHS neurologic diseases, we have performed PHOX2B mutation screening in a group of individuals with Chiari I malformation, confirming the exclusive role of PHOX2B in the pathogenesis of CCHS.