Table 1

Clinical features of patients with congenital myopathy and excess of muscle spindles (CMEMS)

Patient no	1	2	3	4	5
H(O)CM, hypertrophic (obstructive) cardiomyopathy; ASD, atrial septal defect.
*Small fibres and excess of type IIC fibres were reported to be consistent with immaturity and hypotonia.
Reference	de Boode et al,⁵ case 1	de Boode et al,⁵ case 2	Selcen et al⁶	Stassou et al⁷	This report
Age at last follow-up	3 weeks	10 months	14 months	7 months	13 months
Sex	Male	Female	Male	Female	Male
Birth weight	1938 g (75th centile), preterm infant	3370 g (40th centile)	Not available	2460 g (75th centile), preterm infant	2765 g (<3rd centile)
Congenital heart defect	Progressive HOCM	Severe HOCM	HOCM, chaotic atrial tachycardia	HOCM	Mild (transient) HCM
Facial anomalies	Hypertelorism, epicanthal folds, broad nasal bridge, low-set, posteriorly rotated ears	Hypertelorism, broad nasal bridge, low-set, posteriorly rotated and dysplastic ears	Bifrontal hollowing, full cheeks, triangular mouth, high-arched palate	Hypertelorism, low-set ears	Low-set ears, triangular mouth
Short stature	3rd–10th centile	10th centile	Not available	<10th centile	<1st centile
Relative macrocephaly	Yes (98th centile)	No	Increased brain weight on autopsy	Yes (>90th centile)	No
Short/webbed neck	Webbed neck	Short neck	No	Short, webbed neck	Short neck
Lymphoedema	Fetal hydrops	No	No	Congenital generaled oedema	No
Ophthalmologic problems	Cataracta incipiens	No	No	No eye contact at age 3 months	Nystagmus
Neurological signs/development	Generaled hypotonia, absence of spontaneous movements	None mentioned	Generaled muscle weakness, areflexia, joint contractures, bilateral club feet	Flaccid quadriplegia, absent reflexes, contractures of hands, bilateral talipes equinovarus	Generaled hypotonia, delayed motor development
EMG	No abnormalities	Not available	No abnormalities	Myopathic pattern	Not available
Creatine kinase	Normal	Normal	Normal	Normal	Normal
Muscle histology	Excess of small fibres (type IIC), packed or centrally located nuclei, excess of muscle spindles*. Heart: myocardial disarray	Excess of muscle spindles, excess of type IIC fibres	Fibre atrophy with rounded, small-diameter muscle fibres, excess of formations resembling muscle spindles	Abnormally numerous muscle spindles, increased fibre diameter variation	Excess of muscle spindles; fibre atrophy with rounded small-diameter muscle fibres; type II fibre predominance
Others	Polyhydramnios, hepatosplenomegaly, periventricular haemorrhage with consecutive hydrocephalus, respiratory insufficiency	Polyhdramnios, feeding difficulties, parental consanguinity	Ventilatory dependence by age 3 months, mild enlargement of cerebral ventricles neonatal neuroblastoma	Polyhydramnios, postnatal respiratory insufficiency, osteopenia, poor sucking	Intrauterine growth delay, postnatal transitory respiratory insufficiency, poor sucking requiring tube feeding
Outcome	Died at age 3 weeks	Died at age 10 months from HOCM	Died at age 14 months from cardiorespiratory failure	Died at age 7 months from respiratory failure	Alive (14 months)
HRAS mutation	c.35-36GC→TT (G12V)	Negative	c.34G→A (G12S)	c.187G→A (E63K)	c.64C→A (Q22K)