Case#: a 9-year-old boy

DiseaseAssertion: Hypertrophic obstructive cardiomyopathy (HOCM) during clinical screening, presence of the familial mutation in the MYL2 gene MYL2, c.487G > A [p.(Glu163Lys) as pathogenic.

FamilyInfo: a family history of sarcomeric HCM who was diagnosed with hypertrophic obstructive cardiomyopathy (HOCM) during clinical screening. His father suffered from HCM and died 6 years ago in his 3rd decade due to a stroke. The paternal grandfather of the proband and his sister were also diagnosed with HCM. Other affected family members included a paternal uncle and his son as well as a paternal aunt and her son. Genetic testing of the latter family members revealed a mutation in the MYL2 gene.

ParentalTesting: Yes the family members

CasePresentingHPOs: HP:0034313, HP:0031666, HP:0001670

CaseHPOFreeText: He was well and asymptomatic. His weight was 44.6 kg (93rd centile) and height was 150.5 cm (94th centile); heart rate was 60 b.p.m. and right arm blood pressure was 111/67 mmHg with a mean arterial pressure of 83 mmHg. On auscultation, a 2/6 systolic murmur in the 3rd intercostal space at the left sternal edge was audible. N-terminal prohormone of brain natriuretic peptide level was 434 ng/L (normal range <112 ng/L). The echocardiogram showed asymmetric septal hypertrophy (maximal wall thickness 18 mm) of the left ventricle (LV) with mild flow acceleration in the mid-LV cavity (peak systolic velocity 2.6 m/s) consistent with HOCM. Left ventricle systolic function was hyperdynamic with LVEF of 80%. Late gadolinium enhancement (LGE) imaging showed an area of patchy LGE at the level of the maximal LV wall thickness (Figure 4).

CaseNotHPOs: HP:0001635 , HP:0001279, HP:0031656, HP:0001653

CaseNotHPOFreeText: No signs of congestive heart failure and no history of syncope. No systolic anterior movement (SAM) and no mitral regurgitation.

CasePreviousTesting: Clinical screening

Genotyping Method: Genetic testing confirmed

FunctionalAnalysis: NR

Variant: NM_000432.4:c.487G>A

ClinVar: 1051330

CAID: CA386696712

gnomAD: NR

AdditionalInfo: NR