This 16-year-old boy was the first child to non-consanguineous parents.
His parents and two younger siblings were healthy.
He was well until starting school at 7 years of age when he was found to be short in height, slightly myopic, astigmatic and to have subnormal visual acuity.
Endocrinological investigations were performed that initially revealed borderline values for growth hormone (GH) deficiency and he was therefore treated for a period with GH without any beneficiary effect on his growth.
At age 16 years, height and weight was −3 SD below the mean compared with a standardized Swedish growth chart.
Ophthalmological investigations at 10 years of age showed pigmentary retinopathy and optic atrophy.
An electroretinogram was performed and showed a severe rod cone dystrophy.
He had decreased visual acuity, visual fields, color vision, and dark adaption.
Nystagmus has been noted since 14 years of age.
A year later, photophobia and bilateral cataracts were developed.
The cataracts were operated on at 16 years of age.
He is now blind.
At 14 years of age, he was referred for neurological investigations.
A clinical examination showed mild ataxia with tremor, dysmetria and gait instability together with mild to moderate muscle weakness, weak to absent tendon reflexes in the lower extremities, and exercise intolerance.
Audiometric investigations revealed a mild bilateral sensorineural hearing impairment.
At 15 years of age, he had an unprovoked epileptic seizure and he has since then been treated with levetiracetam.
Decreased renal function was identified at 15 years of age, with increased serum creatinine to 145 μmol/l (reference interval 30–90 μmol/l), proteinuria with urine albumine at 244–538 mg/l (reference interval<20 mg/l), and urine albumine/creatinine ratio at 44–59 g/mol (reference interval <3 g/mol).
A renal scintigraphy demonstrated reduced kidney size.
Cr51-EDTA clearance showed a decreased glomerular filtration rate of 42% of normal.
The filtration rate decreased over time to 29% of normal at 16 years of age.
Since 14 years of age, cardiac investigations have demonstrated hypertrophy of the walls of the left ventricle (+3 SD compared with normal) with normal systolic and diastolic function and without obstruction of the outflow.
Mitochondrial investigations were performed at 14 years of age.
Blood levels of lactate and pyruvate were 1.6 and 0.096 mmol/l, respectively, leading to a ratio of 33 (reference interval <20), while cerebrospinal fluid (CSF) levels of lactate and pyruvate were 3.6 and 0.137 mmol/l, respectively, leading to a lactate to pyruvate ratio of 26.
The urinary lactate excretion was normal.
The CSF albumin was increased to 258 mg/l (reference level <225 mg/l) and he also had an increased CSF/plasma albumin ratio of 7.4 (reference level <5).
The serum acyl carnitine profile and muscle carnitine levels were normal.
The serum creatine kinase activity was mildly increased to 5.4 μkat/l (reference interval <3.5 μkat/l).