Table 1.

Data on probands with deletion g.[84897_87399del], p.Arg2478_Asp2512del of nebulin gene exon 55 (del55). Mutations are reported based on the DNA sequence GenBank NT_005151.12 using the first nucleotide of the nebulin translation initiation site in exon three as the starting point, and on the protein sequence GenBank P20929. Clinical categories of the patients were determined according to the criteria published by the ENMC International Consortium on Nemaline Myopathy.

Patient number	Form of NM	Mutation in NEB (M) and predicted effect of it on nebulin protein (P)	Clinical features
Patient 1-1	Severe	M: Homozygous del55	Progressive respiratory insufficiency after surgery at 8 yrs.
		P: 35 aa missing, representing one repeat domain, possibly impaired tropomyosin binding	Walked without support for very short distances aged 7, but mainly uses wheelchair or stroller. Current age 15 yrs. Mechanically ventilated
Patient 1–2	Severe	M: Homozygous del55	Arthrogryposis at birth. Did not achieve walking.
		P: See Pt 1	Mechanically ventilated, currently aged 5 yrs.
Patient 2-11	Severe	M: Homozygous del55	Did not achieve walking. Permanently ventilated from age 11 months, deceased at 19 yrs.
		P: See Pt 1
Patient 2-21	Severe	M: Homozygous del55	Did not achieve sitting or walking. Mechanically ventilated since the age of 4 months, current age 21 yrs.
		P: See Pt 1
Patient 3-11	Typical	M: Homozygous del55	Markedly weak antigravity movements at birth. Requires mechanical ventilation at night since the age of 7. Ambulant at 16 years, uses wheelchair only occasionally.
		P: See Pt 1
Patient 3-21	Not classified	M: Homozygous del55	No data available
		P: See Pt 1
Patient 4	Intermediate	M: Homozygous del55	Able to sit but did not achieve walking. Tracheostomy at 2 years, night-time ventilation. Current age 10 yrs.
		P: See Pt 1
Patient 5	Intermediate	M: Homozygous del55	Able to walk using walker. Uses night-time ventilation.
		P: See Pt 1	Current age 7 yrs.
Patient 6¤	Typical	M: Homozygous del55	Acute respiratory distress at 3 months, found to have isolated Complex I deficiency. Ambulant.
		P: See Pt 1
Patient 7	Severe	M: Homozygous del55	Died at the age of 1 month.
		P: See Pt 1
Patient 8	Severe	M: Heterozygous del55*	Ventilator dependent and tube fed, little spontaneous movement.
		P: See Pt 1
Patient 9	Severe	M: Heterozygous del55*	Died at the age of 2.5 months.
		P: See Pt 1
Patient 10	Intermediate	M: Intron 23, g.42331G>C	An affected twin brother died at the age of 9 months from infection. Patient permanently ventilated from age 9 months, current age 7 yrs, did not achieve walking.
		P: Abnormal splicing of exon 24
		M: Del55
		P: See Pt 1
Patient 11		M: Intron 4, g.3543G>A	No hypotonia in the neonatal period, achieved sitting but not walking, died at 3.5 yrs from respiratory infection
	Intermediate	P: Skipping of exon 4 p.Tyr13_Glu26del, 14 aa missing in the TMOD-binding region
		M: Del55
		P: See Pt 1
Patient 12		M: Intron 79, g.122400G>C	Not walking at 15 months of age. Does not require assisted ventilation.
	Typical	P: Skipping of exon 79, p.His3693_Gln3727del
		M: Del55
		P: See Pt 1
Patients 13-1 and 13-2		M: Intron 151 g.207199_207207delGTAAGTGAT	No data available
	Unclassified	P: Skipping of exon 151, p.Asn5650_Asp5686del, 37 aa encoding one repeat domain missing, ?impaired tropomyosin and desmin binding
		M: Del55
		P: See Pt 1
Patient 14-1	Severe	M: Heterozygous del55*	No spontaneous antigravity movements. Died at the age of 5 months.
		P: See Pt 1

^*The second mutation awaits identification,

¹published by Anderson et al. (2004),

^¤Patient 6 was described by Lamont and co-workers in 2004 [6]