We describe a case of the juvenile form of Pompe's disease that presented as primary alveolar hypoventilation due to respiratory muscle involvement. This 17-year-old girl had been asymptomatic until this admission, although she had a delayed puberty. Arterial blood gas analysis, pulmonary function test as well as physical findings were compatible with chronic alveolar hypoventilation syndrome. Since she had lower extremity muscle weakness and pseudomyotonic discharge on electromyography a muscle biopsy was done, which revealed glycogen storage disease. The patient was managed successfully with nasal intermittent positive pressure ventilation.
Adolescent ; Chronic Disease ; Female ; Glycogen Storage Disease Type II/*complications/pathology ; Humans ; Hypoventilation/*etiology/therapy ; Intermittent Positive-Pressure Ventilation ; Muscles/pathology ; Pulmonary Alveoli

OBJECTIVETo evaluate clinical characteristics and PHOX2B gene mutations in congenital central hypoventilation syndrome (CCHS) and to facilitate the early diagnosis and management of CCHS and reduce the misdiagnosis.

METHODClinical data of 3 infants with CCHS who had recurrent respiratory failure episodes and dependent on mechanical ventilation support in 3 from March 2008 to April 2012 were analyzed, and blood gas analysis was performed respectively in the awaken and sleeping status. Gene sequencing was used for detection of PHOX2B gene mutation.

RESULTAll the three patients had adequate ventilation during awaken time, but they presented with abnormal frequency and shallow breathing associated with alveolar hypoventilation after falling asleep. Blood gas analysis showed hypercapnia and CO2 partial pressure was consistently over 60 mm Hg (1 mm Hg = 0.133 kPa) after falling asleep, which is in accordance with the clinical features of CCHS. The PHOX2B gene sequencing showed that 6 GCN repeats were inserted at exon3 of PHOX2B in case 1, at same position, 5 GCN repeats were inserted in case 2 and 3.

CONCLUSIONNormal ventilation in awaken status while shallow slow breathing accompanied with hypercapnia in sleep are the main clinical characteristics of CCHS, which requires mechanical ventilation. Acquired mutation in exon 3 of PHOX2B gene encoding repeated GCN sequence seems to be the molecular etiology of these three patients.

Alanine ; genetics ; Blood Gas Analysis ; Carbon Dioxide ; blood ; DNA Mutational Analysis ; Exons ; Female ; Homeodomain Proteins ; genetics ; Humans ; Hypercapnia ; diagnosis ; etiology ; Hypoventilation ; congenital ; diagnosis ; genetics ; therapy ; Infant ; Infant, Newborn ; Male ; Mutation ; Oxygen Inhalation Therapy ; Polymerase Chain Reaction ; Polysomnography ; Respiration, Artificial ; Retrospective Studies ; Sleep Apnea, Central ; diagnosis ; genetics ; therapy ; Transcription Factors ; genetics