Table 1 Clinical features of families 1, 2 & 3

Genotype

HEXB HOM c.445 + 1G > T

N/K

MBOAT7 HOM c.758_778del

MBOAT7 HOM c.758_778del

N/K

MBOAT7 HOM c.758_778del

MBOAT7 HOM c.758_778del

MBOAT7 HOM c.758_778del

MBOAT7 HOM c.758_778del

Sex

F

M

M

M

F

F

M

M

F

Age at assessment (years)

20 m

Not assessed (deceased at 18 m)

20

18

16

19

9

8y 1 m

12y

Gestation weeks

FT

N/K

FT

FT

N/K

N/K

FT

FT

FT

Birth weight kg (SD)

3.0 (−0.9)

N/K

3.0 (−1.16)

2.9 (− 1.38)

N/K

N/K

2.8

1.5 (−4.6)

1.8 (−3.86)

Height cm (SD)

89 (+ 2.27)

N/K

172.5 (−0.69)

168.8 (−1.2)

N/K

N/K

106.7 (−4.58)

106.7 (−3.93)

127 (−3.2)

Weight kg (SD)

8.5 (−2.67)

N/K

55 (−1.95)

68 (+ 0.09)

N/K

N/K

30 (+ 0.34)

N/K

N/K

Head circumference cm (SD)

51 (+ 2.2)

N/K

50 (−2.8)

55.5 (−1.03)

53.6 (− 1.25)

55.5 (−0.01)

54 (− 1.9)

49 (−3.11)

52 (− 1.81)

 Intellectual disability

+

+

Mod-Severe

Severe

Mod-Severe

Mod-Severe

Mod-Severe

Mod-Severe

Mod-Severe

 Speech delay/impairment

Non-verbal

+

Non-verbal

Non-verbal

+

+

Non-verbal

Non-verbal

Non-verbal

 Developmental delay

+

+

+

+

+

+

+

+

+

 Age walking

N/A

N/A

3.5y

4y

N/A

N/A

3.5y

>4y

4y

 Macrocephaly

+

N/K

–

–

–

–

–

–

–

 Microcephaly

–

N/K

+

–

–

–

–

+

+

 Seizures

Onset 7 m

GTCS

Regression

+

Onset 1.5y

Focal/ multifocal infantile

Onset 2.5y

Focal/ multifocal infantile

Febrile seizures in infancy

Febrile seizures in infancy

Febrile seizures in infancy

Onset in infancy

GTCS

Onset in infancy

GTCS

 Hypotonia

+

N/K

+

+

+

+

N/K

+

+

 Behavioural problems

N/A

N/A

–

Aggressive episodes

–

–

–

Aggressive episodes

Hyperactivity

Aggressive episodes

Other features

Strabismus

Nystagmus

Visual loss

Hearing loss

Hepatosplenomegaly

Deceased aged 1.5 years

Unable to walk

Unable to walk

Reduced physical activity level