Case: Pedigree 6 proband, 4yo at diagnosis

CasePresentingHPOs: HP:0001644, HP:0001657, HP:0001290, HP:0002033, HP:0001712, HP:0025169, HP:0001657 (dilated cardiomyopathy, prolonged QT interval, generalized hypotonia, poor suck, left ventricular hypertrophy, Left ventricular systolic dysfunction, prolonged QT interval)

HPOsFreeText: skeletal involvement, clinical severity: moderate to mild, bork at 39 weeks gestation, required tube feeding from 1wk-2yo, head lag, able to exert antigravity movements of her biceps, iliopsoas, and quadriceps, wiggle her fingers and toes, able to pedal her tricycle independently, globular left ventricle, end‐diastolic dimension: 3.14 cm, z‐score: 3.9, left ventricular diastolic dysfunction, fractional shortening of 25%, left ventricular EF of 46%

Skeletal muscle biopsy showed increased variations in fiber size with scattered small, round fibers, acceptable sarcomeric organization and striation with occasional fibers showing a spectrum of focal myofibrillary disorganization and irregular thickening of Z‐bands, absence of type 1 fibers, hypertrophy of type 2 fibers, normal motor and sensory responses of the left upper and lower limb muscles, small amplitude and short duration polyphasic motor units with early recruitment

CaseNotHPOs: HP:0009830, HP:0006802 (neuropathy, Abnormal anterior horn cell morphology)

CasePreviousTesting: sequencing of four genes associated with CFTD (SEPN1, TPM3, ACTA1, RYR1) were normal

CaseGenotyping: karyotype, chromosomal microarray, MYH7 sequencing

Variant: NM_000257.3:c.5655+1G>A

CAID: CA389034770, http://reg.clinicalgenome.org/redmine/projects/registry/genboree_registry/by_caid?caid=CA389034770

gnomAD: n/a