OBJECTIVE: To explore the clinical features, lysosomal enzymatic [acid α-glucosidase (GAA)] activities and genetic variants in a child with late-onset Pompe disease (LOPD). METHODS: Clinical data of a child who had presented at the Genetic Counseling Clinic of West China Second University Hospital in August 2020 was retrospectively analyzed. Blood samples were collected from the patient and her parents for the isolation of leukocytes and lymphocytes as well as DNA extraction. The activity of lysosomal enzyme GAA in leukocytes and lymphocytes was analyzed with or without addition of inhibitor of GAA isozyme. Potential variants in genes associated with neuromuscular disorders were analyzed, in addition with conservation of the variant sites and protein structure. The remaining samples from 20 individuals undergoing peripheral blood lymphocyte chromosomal karyotyping were mixed and used as the normal reference for the enzymatic activities. RESULTS: The child, a 9-year-old female, had featured delayed language and motor development from 2 years and 11 months. Physical examination revealed unstable walking, difficulty in going upstairs and obvious scoliosis. Her serum creatine kinase was significantly increased, along with abnormal electromyography, whilst no abnormality was found by cardiac ultrasound. Genetic testing revealed that she has harbored compound heterozygous variants of the GAA gene, namely c.1996dupG (p.A666Gfs*71) (maternal) and c.701C>T (p.T234M) (paternal). Based on the guidelines from the American College of Medical Genetics and Genomics, the c.1996dupG (p.A666Gfs*71) was rated as pathogenic (PVS1+PM2_Supporting+PM3), whilst the c.701C>T (p.T234M) was rated as likely pathogenic (PM1+PM2_Supporting+PM3+PM5+PP3). The GAA in the leukocytes from the patient, her father and mother were respectively 76.1%, 91.3% and 95.6% of the normal value without the inhibitor, and 70.8%, 112.9% and 128.2% of the normal value with the inhibitor, whilst the activity of GAA in their leukocytes had decreased by 6 ~ 9 times after adding the inhibitor. GAA in lymphocytes of the patient, her father and mother were 68.3%, 59.0% and 59.5% of the normal value without the inhibitor, and 41.0%, 89.5% and 57.7% of the normal value with the inhibitor, the activity of GAA in lymphocytes has decreased by 2 ~ 5 times after adding the inhibitor. CONCLUSION The child was diagnosed with LOPD due to the c.1996dupG and c.701C>T compound heterozygous variants of the GAA gene. The residual activity of GAA among LOPD patients can range widely and the changes may be atypical. The diagnosis of LOPD should not be based solely on the results of enzymatic activity but combined clinical manifestation, genetic testing and measurement of enzymatic activity.
Humans ; Child ; Male ; Female ; Glycogen Storage Disease Type II/pathology* ; Retrospective Studies ; alpha-Glucosidases/genetics* ; Mothers ; Lysosomes/pathology* ; Mutation

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

Adult ; Diagnosis, Differential ; Female ; Glycogen ; metabolism ; Glycogen Storage Disease Type II ; pathology ; Humans ; Liver ; metabolism ; pathology ; Muscle, Skeletal ; metabolism ; pathology ; Muscular Dystrophies, Limb-Girdle ; pathology ; Pyomyositis ; pathology ; Young Adult

OBJECTIVETo summarize clinical features and diagnosis of Chinese infantile patients with glycogen storage disease type II (GSD II).

METHODSix infant patients with GSD II diagnosed from January 2012 to June 2014 in the Department of Pediatrics, Peking University First Hospital were enrolled into this study. Clinical information of the 6 patients, including clinical manifestation, blood biochemistry, chest X-ray, echocardiogram, electrocardiogram, acid alpha-glucosidase (GAA) activity and GAA gene mutation analysis by direct sequencing of polymerase chain reaction (PCR) product were reviewed.

RESULTOf the 6 patients, five were female and one was male, five of whom were classic infantile type while the other one was atypical. The age of onset ranged from birth to 3-month-old. All patients had varying degrees of generalized muscle weakness, hypotonia and development retardation or retrogression. Other common findings were feeding difficulties in two patients, tongue weakness in two patients, respiratory distress in four patients, macroglossia in one patient, and hepatomegaly in two patients. Left ventricular hypertrophy and cardiomegaly were obvious in all the six patients. All six patients were found to have a enlarged heart in physical examination, and three patients who underwent a chest X-ray examination had an enlarged heart shadow. Four patients who had an echocardiography were found to have myocardial hypertrophy. The electrocardiogram in three patients showed short PR intervals and high voltage. The creatine kinase (CK) levels were three to seven times elevated. The mildest elevated CK was 441 IU/L, and the highest CK level was 1 238 U/L. Assay of GAA enzyme activity in whole blood showed significantly reduced activity (1.3 nmol/ (spot·d) to 2 nmol/(spot·d)) in the patients tested. Gene sequencing in 4 patients showed 8 pathogenic mutations, including 6 missense mutations, one nonsense mutation and one frameshift mutation. The missense mutations were c.998C > A (p.Thr333Lys), c.1280T > C (p.Met427Thr), c.1760T > C (p.Leu587Pro), c.1924G > T (p.Val642Phe), c.2012T > A (p.Met671Lys) and c.2105G > A (p.Arg702His). The nonsense mutation was c2662G > T (p.Glu888X), and the frameshift mutation was c2812_2813delTG (p.Cys938fs). The 5 classic infantile patients died at the age of 7 to 22 months. The atypical infantile patient was 2 years and five months old according to our latest follow up.

CONCLUSIONInfantile GSD II had similar motor manifestations and cardiac involvements, blood biochemical test, imaging findings, enzyme assays, though there were slight differences. The probability of GSD II should be taken into consideration if an infant has both muscular disease and cardiac involvement.

Asian Continental Ancestry Group ; Female ; Glycogen Storage Disease Type II ; diagnosis ; pathology ; Humans ; Infant ; Infant, Newborn ; Macroglossia ; congenital ; Male ; Muscle Weakness ; Mutation ; Mutation, Missense ; Polymerase Chain Reaction ; alpha-Glucosidases ; genetics ; metabolism

OBJECTIVETo analyze and summarize the characteristics of glycogen storage disease type II (Pompe disease) patients according to the clinical description and prognosis.

METHODSeventeen Chinese patients diagnosed by acid alpha-glucosidase (GAA) enzyme activity test were reviewed. Clinical data tables were designed. Interviews were made via phone calls. Information was collected to reach the objective.

RESULTFour of 17 patients diagnosed by acid alpha-glucosidase are infantile-onset, symptoms started between 2 to 6 months after birth with increased serum creatine kinase and cardiac problems, with or without respiratory concerns. Other 13 patients were later-onset cases, and their symptoms started between 2 to 22 years of age with increased serum creatine kinase. Eleven later-onset patients started with muscle weakness, 2 patients developed respiratory insufficiency, 2 patients showed scoliosis, and 1 patient expressed increased serum creatine kinase with abnormal liver function. Just 3 of the later-onset patients were treated with mechanical ventilator and adjuvant therapy, others were not. All patients' acid alpha-glucosidase (GAA) enzyme activity analysis showed lower than 10% of normal. Fourteen patients were tested by muscle biopsy pathology, and 9 of them progressed to glycogen storage disease type II; 10 patients received genetic analysis, and 6 of them had two mutations which cause the disorder. Twelve of the 17 patients were interviewed successfully. In 3 of the infant-onset patients the disease resulted in death from respiratory failure, and 1 is still alive at the age of 1 year and 7 months. In 4 of 8 later-onset patients the disease resulted in death from respiratory failure between 3 to 5 years after onset of symptoms. Three of 4 survivors had increased muscle weakness, and 1 patient kept alive with ventilator without any changes. Seven of 12 interviewed patients died, the mortality rate was 58.3%.

CONCLUSIONGlycogen storage disease type II (Pompe disease) present differently in the clinic. Infant-onset Pompe disease is mainly characterized by generalized muscle weakness and obvious cardiac involvement. It's a dangerous disease, with high mortality rate. Later-onset Pompe disease is characterized by chronic proximal muscle weakness and respiratory insufficiency. GAA enzyme activity analysis, muscle biopsy and genetic analysis used to support the diagnosis of Pompe disease. Prognosis of the disease depends on age of onset and respiratory muscle involvement.

Adolescent ; Biopsy ; Cardiomyopathies ; epidemiology ; etiology ; Child ; Child, Preschool ; Clinical Enzyme Tests ; Creatine Kinase ; blood ; Female ; Follow-Up Studies ; Glucan 1,4-alpha-Glucosidase ; genetics ; metabolism ; Glycogen Storage Disease Type II ; diagnosis ; genetics ; pathology ; Humans ; Infant ; Male ; Muscle Weakness ; epidemiology ; etiology ; Prognosis ; Respiratory Insufficiency ; epidemiology ; Retrospective Studies ; Young Adult