Identification of patients with Pompé disease using routine pathology results: PATHFINDER (creatine kinase) study

Detection of LAMA2 c.715C>G:p.R239G mutation in a newborn with raised creatine kinase: A case report

BACKGROUND

We report a rare case of primary clinical presentation featuring elevated creatine kinase (CK) levels in a neonate, which is associated with the LAMA2 gene. In this case, a heterozygous mutation in exon5 of the LAMA2 gene, c.715C>G (resulting in a change of nucleotide number 715 in the coding region from cytosine to guanine), induced an amino acid alteration p.R239G (No. 239) in the patient, representing a missense mutation. This observation may be elucidated by the neonatal creatine monitoring mechanism, a phenomenon not previously reported.

CASE SUMMARY

We analysed the case of a neonate presenting solely with elevated CK levels who was eventually discharged after supportive treatment. The chief complaint was identification of increased CK levels for 15 d and higher CK values for 1 d. Admission occurred at 18 d of age, and despite prolonged treatment with creatine and vitamin C, the elevated CK levels showed limited improvement. Whole exome sequencing revealed the presence of a c.715C>G mutation in LAMA2 in the newborn, correlating with a clinical phenotype. However, the available information offers insufficient evidence for clinical pathogenicity.

CONCLUSION

Mutations in LAMA2 are associated with the clinical phenotype of increased neonatal CK levels, for which no specific treatment exists. Whole genome sequencing facilitates early diagnosis.

Screening for patients with Gaucher's disease using routine pathology results: PATHFINDER (ferritin, alkaline phosphatase, platelets) study

AIMS

Lysosomal β-glucocerebrosidase A (GBA) deficiency causes Gaucher disease (GD), a recessive disorder caused by bi-allelic mutations in GBA. The prevalence of GD is associated with ethnicity but largely unknown and potentially underestimated in many countries. GD may manifest with organomegaly, bone involvement, and neurological symptoms as well as abnormal laboratory biomarkers. This study attempted to screen for GD in patients using abnormal platelet, alkaline phosphatase (ALP), and ferritin results from laboratory databases.

METHODS

Electronic laboratory databases were interrogated using a 2- to 4-year time interval to identify from clinical biochemistry records patients with a phenotype of reduced platelets (<150 × 10⁹ /L) and either elevated ALP (>130 iu/L) or ferritin [>150 (female) or >250 µg/L (male)]. The mean value over the screening window was used to reduce variability in results. A dried blood spot sample was collected for the determination of GBA activity in patients meeting these criteria. If low GBA activity was found, then the concentration of the GD-specific biomarker glucosyl-sphingosine (lyso-GB1) was assayed, and the GBA gene sequenced.

RESULTS

Samples were obtained from 1058 patients; 232 patients had low GBA activity triggering further analysis. No new cases of GD with homozygosity for pathogenic variants were identified, but 12 patients (1%) were identified to be carriers of a pathogenic variant in GBA.

CONCLUSIONS

Pathology databases hold routine information that can be used to screen for patients with inherited errors of metabolism. However, biochemical screening using mean platelets, ALP, and ferritin has a low yield for unidentified cases of GD.