Ophthalmological findings in infantile type of so-called neuronal ceroid lipofuscinosis

Management of CLN1 Disease: International Clinical Consensus

BACKGROUND

CLN1 disease (neuronal ceroid lipofuscinosis type 1) is a rare, genetic, neurodegenerative lysosomal storage disorder caused by palmitoyl-protein thioesterase 1 (PPT1) enzyme deficiency. Clinical features include developmental delay, psychomotor regression, seizures, ataxia, movement disorders, visual impairment, and early death. In general, the later the age at symptom onset, the more protracted the disease course. We sought to evaluate current evidence and to develop expert practice consensus to support clinicians who have not previously encountered patients with this rare disease.

METHODS

We searched the literature for guidelines and evidence to support clinical practice recommendations. We surveyed CLN1 disease experts and caregivers regarding their experiences and recommendations, and a meeting of experts was conducted to ascertain points of consensus and clinical practice differences.

RESULTS

We found a limited evidence base for treatment and no clinical management guidelines specific to CLN1 disease. Fifteen CLN1 disease experts and 39 caregivers responded to the surveys, and 14 experts met to develop consensus-based recommendations. The resulting management recommendations are uniquely informed by family perspectives, due to the inclusion of caregiver and advocate perspectives. A family-centered approach is supported, and individualized, multidisciplinary care is emphasized in the recommendations. Ascertainment of the specific CLN1 disease phenotype (infantile-, late infantile-, juvenile-, or adult-onset) is of key importance in informing the anticipated clinical course, prognosis, and care needs. Goals and strategies should be periodically reevaluated and adapted to patients' current needs, with a primary aim of optimizing patient and family quality of life.

Ocular Manifestations of Neuronal Ceroid Lipofuscinoses

Neuronal ceroid lipofuscinoses (NCLs) are a group of rare neurodegenerative storage disorders associated with devastating visual prognosis, with an incidence of 1/1,000,000 in the United States and comparatively higher incidence in European countries. The pathophysiological mechanisms causing NCLs occur due to enzymatic or transmembrane defects in various sub-cellular organelles including lysosomes, endoplasmic reticulum, and cytoplasmic vesicles. NCLs are categorized into different types depending upon the underlying cause i.e., soluble lysosomal enzyme deficiencies or non-enzymatic deficiencies (functions of identified proteins), which are sub-divided based on an axial classification system. In this review, we have evaluated the current evidence in the literature and reported the incidence rates, underlying mechanisms and currently available management protocols for these rare set of neuroophthalmological disorders. Additionally, we also highlighted the potential therapies under development that can expand the treatment of these rare disorders beyond symptomatic relief.

Presymptomatic treatment of classic late-infantile neuronal ceroid lipofuscinosis with cerliponase alfa

Background

Neuronal ceroid lipofuscinosis type 2 (CLN2 disease) is a rare rapidly progressive neurodegenerative disorder, resulting in early death. Intracerebroventricular enzyme replacement therapy (ERT) with cerliponase alfa is now available and has shown to delay disease progression in symptomatic patients. It is yet unknown if cerliponase alfa can prevent disease onset in presymptomatic patients.

Results

We evaluated the effect of 2 years of intracerebroventricular ERT in two siblings with CLN2 disease, one symptomatic (age 47 months) and one presymptomatic (age 23 months) at treatment start, using the CLN2 Clinical Rating Scale (CLN2 CRS), Gross Motor Function Measure-66 (GMFM-66) for motor function, Bayley Scales of Infant and Toddler Development, 3rd Edition, Dutch (BSID-III-NL) for neurocognitive development, brain MRI, and visual evoked potentials (VEP), electroretinogram (ERG) and retinoscopy for visual function. On the CLN2 CRS patient 1 showed a decline from 3 to 2 in the combined motor and language score due to regression in language use (CLN2 CRS total score after 2 years of treatment: 8), whereas a decline of 2 or more points in the combined motor and language score would be expected without treatment. Patient 2 retained the maximum score of 3 in all 4 subdomains (CLN2 CRS total score after 2 years of treatment: 12). The GMFM-66 total score declined from 46 to 39 in patient 1 and showed an age-appropriate increase from 66 to 84 in patient 2. Cognitive-developmental age decreased from 24 to 11 months in patient 1, whereas an increase in cognitive-developmental age from 21 to 39 months was seen in patient 2. Cerebral and cerebellar atrophy observed on MRI in patient 1 at age 42 months (before treatment) was not observed in patient 2 at age 48 months (after 2 years of treatment).

Conclusion

We show that cerliponase alfa is able to delay the onset of symptoms when treatment is started in a presymptomatic stage of CLN2 disease. Our results advocate the start of treatment at an early age before symptom onset, but should be confirmed in a larger cohort study.

Proteomics insights into infantile neuronal ceroid lipofuscinosis (CLN1) point to the involvement of cilia pathology in the disease

Mutations in the depalmitoylation enzyme, palmitoyl protein thioesterase (PPT1), result in the early onset neurodegenerative disease known as Infantile Neuronal Ceroid Lipofuscinosis. Here, we provide proteomic evidence suggesting that PPT1 deficiency could be considered as a ciliopathy. Analysis of membrane proteins from brain enriched for acylated proteins from neonate Ppt1 knock out and control mice revealed a list of 88 proteins with differential expression levels. Amongst them, we identified Rab3IP, which regulates ciliogenesis in concert with Rab8 and Rab11. Immunostaining analysis revealed that PPT1 is localized in the cilia. Indeed, an unbiased proteomics analysis on isolated cilia revealed 660 proteins, which differed in their abundance levels between wild type and Ppt1 knock out. We demonstrate here that Rab3IP, Rab8 and Rab11 are palmitoylated, and that palmitoylation of Rab11 is required for correct intracellular localization. Cells and brain preparations from Ppt1-/- mice exhibited fewer cells with cilia and abnormally longer cilia, with both acetylated tubulin and Rab3IP wrongly distributed along the length of cilia. Most importantly, the analysis revealed a difference in the distribution and levels of the modified proteins in cilia in the retina of mutant mice versus the wildtype, which may be important in the early neurodegenerative phenotype. Overall, our results suggest a novel link between palmitoylated proteins, cilial organization and the pathophysiology of Neuronal Ceroid Lipofuscinosis.

Oral cysteamine bitartrate and N-acetylcysteine for patients with infantile neuronal ceroid lipofuscinosis: a pilot study

BACKGROUND

Infantile neuronal ceroid lipofuscinosis is a devastating neurodegenerative lysosomal storage disease caused by mutations in the gene (CLN1 or PPT1) encoding palmitoyl-protein thioesterase-1 (PPT1). We have previously reported that phosphocysteamine and N-acetylcysteine mediate ceroid depletion in cultured cells from patients with this disease. We aimed to assess whether combination of oral cysteamine bitartrate and N-acetylcysteine is beneficial for patients with neuronal ceroid lipofuscinosis.

METHODS

Children between 6 months and 3 years of age with infantile neuronal ceroid lipofuscinosis with any two of the seven most lethal PPT1 mutations were eligible for inclusion in this pilot study. All patients were recruited from physician referrals. Patients received oral cysteamine bitartrate (60 mg/kg per day) and N-acetylcysteine (60 mg/kg per day) and were assessed every 6-12 months until they had an isoelectric electroencephalogram (EEG, attesting to a vegetative state) or were too ill to travel. Patients were also assessed by electroretinography, brain MRI and magnetic resonance spectroscopy (MRS), and electron microscopic analyses of leukocytes for granular osmiophilic deposits (GRODs). Children also underwent physical and neurodevelopmental assessments on the Denver scale. Outcomes were compared with the reported natural history of infantile neuronal ceroid lipofuscinosis and that of affected older siblings. This trial is registered with ClinicalTrials.gov, number NCT00028262.

FINDINGS

Between March 14, 2001, and June 30, 2012, we recruited ten children with infantile neuronal ceroid lipofuscinosis; one child was lost to follow-up after the first visit and nine patients (five girls and four boys) were followed up for 8 to 75 months. MRI showed abnormalities similar to those in previous reports; brain volume and N-acetyl aspartic acid (NAA) decreased steadily, but no published quantitative MRI or MRS studies were available for comparison. None of the children acquired new developmental skills, and their retinal function decreased progressively. Average time to isoelectric EEG (52 months, SD 13) was longer than reported previously (36 months). At the first follow-up visit, peripheral leukocytes in all nine patients showed virtually complete depletion of GRODs. Parents and physicians reported less irritability, improved alertness, or both in seven patients. No treatment-related adverse events occurred apart from mild gastrointestinal discomfort in two patients, which disappeared when liquid cysteamine bitartrate was replaced with capsules.

INTERPRETATION

Our findings suggest that combination therapy with cysteamine bitartrate and N-acetylcysteine is associated with delay of isoelectric EEG, depletion of GRODs, and subjective benefits as reported by parents and physicians. Our systematic and quantitative report of the natural history of patients with infantile neuronal ceroid lipofuscinosis provides a guide for future assessment of experimental therapies.

FUNDING

National Institutes of Health.

Funduscopic and angiographic appearance in the neuronal ceroid lipofuscinoses

PURPOSE

To characterize the retinal features of neuronal ceroid lipofuscinoses (NCLs) and to determine if retinal abnormalities are detectable in carriers of these autosomal recessively inherited diseases.

METHODS

Carriers of the NCLs and their affected children underwent ophthalmic examination including color fundus photography in all patients and fluorescein angiography in selected patients. Twenty-nine patients with NCL were examined and photographed: 3 with infantile form, 2 with late-infantile form, and 24 with juvenile form. Fourteen patients underwent fluorescein angiography.

RESULTS

Infantile and late-infantile retinal findings include fine retinal pigment epithelium pigment atrophy with no bone spicule changes and disk pallor. Juvenile retinal findings include macular retinal pigment epithelium atrophy and pigment stippling (>50%), epiretinal membrane (33%), bull's eye maculopathy (25%), and peripheral bone spicules (46%) and variable disk pallor. Fluorescein angiography of juvenile patients demonstrated diffuse retinal pigment epithelium atrophy with stippled hyperfluorescence (93%). Heterozygous NCL carriers had no identifying retinal abnormalities.

CONCLUSION

Significant variability exists in the retinal appearance of the NCLs, but, in general, ophthalmoscopy and fluorescein angiography distinguish these patients from other more common blinding disorders of childhood such as retinitis pigmentosa and Stargardt disease. Examining retinas of parents of affected children does not aid in the diagnosis of NCL.

Retinitis pigmentosa, pigmentary retinopathies, and neurologic diseases

Retinitis pigmentosa (RP) refers to a group of inherited retinal diseases with phenotypic and genetic heterogeneity. The pathophysiologic basis of the progressive visual loss in patients with RP is not completely understood but is felt to be due to a primary retinal photoreceptor cell degenerative process mainly affecting the rods of the peripheral retina. In most cases RP is seen in isolation (nonsyndromic), but in some other cases it may be a part of a genetic, metabolic, or neurologic syndrome or disorder. Nyctalopia, or night blindness, is the most common symptom of RP. The classic fundus appearance of RP includes retinal pigment epithelial cell changes resulting in retinal hypo- or hyperpigmentation ("salt-and-pepper"), retinal granularity, and bone spicule formation. The retinal vessels are often narrowed or attenuated and there is a waxy pallor appearance of the optic nerve head. Electroretinography will demonstrate rod and cone photoreceptor cell dysfunction and is a helpful test in the diagnosis and monitoring of patients with RP. A detailed history with pedigree analysis, a complete ocular examination, and the appropriate paraclinical testing should be performed in patients complaining of visual difficulties at night or in dim light. This review discusses the clinical manifestations of RP as well as describing the various systemic diseases, with a special emphasis on neurologic diseases, associated with a pigmentary retinopathy.

Electroretinographic and clinicopathologic correlations of retinal dysfunction in infantile neuronal ceroid lipofuscinosis (infantile Batten disease)

Infantile neuronal ceroid lipofuscinosis (INCL) is an autosomal recessive disease that results from deficiency of palmitoyl-protein thioesterase-1 (PPT1). INCL leads to retinal blindness, neurodegeneration, and early death. We studied the clinical features and electroretinogram (ERG) in three patients and histopathologic and immunofluorescence analyses of the retina in the third patient, who died at 3 years 2 months of age. The ERGs for the 2 youngest patients (ages 1.7 and 2.3 years) showed normal scotopic bright flash a-wave amplitudes with severe loss of b-wave (electronegative ERG), indicating dysfunction at or proximal to the photoreceptor inner segments. The third patient at 2.9 years of age showed subnormal a-wave amplitudes and even greater loss of b-wave amplitudes. Histopathology revealed reduced cell numbers in all retinal layers, including the inner nuclear layer (INL), and a central epiretinal membrane. Autofluorescent lipofuscin granules were present in all neuronal cell types in the retina. Cones and rods in the parafoveal area were labeled with a cone cytoplasmic marker, mAb 7G6, and anti-rhodopsin, respectively, and had extremely short outer segments. The periphery showed better preservation but photoreceptor outer segments were short. Immunofluorescence revealed degenerate rods and cones throughout the retina with better preservation in the periphery. Autofluorescent lipofuscin was found in all cell types, including cone inner segments, to a greater degree than seen in normal ageing. The ERG findings support the existence early in the disease of a relative pre- or post-synaptic block of effective neurotransmission from photoreceptor inner segments to the second order bipolar neurons.

The Finnish Disease Heritage III: the individual diseases

This article is the third and last in a series entitled The Finnish Disease Heritage I-III. All the 36 rare hereditary diseases belonging to this entity are described for clinical and molecular genetic purposes, based on the Finnish experience gathered over a period of half a century. In addition, five other diseases are mentioned. They may be included in the list of the "Finnish diseases" after adequate complementary studies.

EEG and evoked potentials in infantile neuronal ceroid-lipofuscinosis

Sixteen children with infantile neuronal ceroid-lipofuscinosis (INCL), age range 0.5 to 5.4 years, were studied using EEG, electroretinograms (ERG), visual evoked potentials (VEP) and somatosensory evoked potentials (SEP). Electroencephalography was the first of these examinations to reveal abnormalities, however the EEG may be normal at the preclinical stage. The first abnormality to appear was an attenuated reaction to passive eye opening and closing which was followed by disturbances in background activity and diminution in amplitude, and by disappearance of sleep spindles. The gradual disappearance of posterior rhythm reactivity and of sleep spindles suggests that thalamic dysfunction progresses with time. EEG inactivity appeared by the age of 3 years. Evoked potentials were normal in the early stages of the disease. SEP showed abnormalities at Stage 2 (1.7 years), while ERG and VEP abnormalities appeared at Stage 3 (by the age of 2.5 years). All neurophysiological reactions examined were abolished by the age of 4 years. Follow-up EEG gives important hints as to the early diagnosis of INCL. Progression of the disease can be followed by evoked potentials which may also be helpful in the differential diagnostics.

MRI of the brain, EEG sleep spindles and SPECT in the early diagnosis of infantile neuronal ceroid lipofuscinosis

Two patients with infantile neuronal ceroid lipofuscinosis are presented whose clinical diagnosis was based on the typical clinical picture, together with absent sleep spindles and MRI findings (hypointense thalami and hyperintense periventricular white matter) as early as 18 months in one girl. In addition to a flat cortical SEP, these abnormalities appeared earlier than the typical ERG and VEP findings used previously for clinical diagnosis of this condition. MRI of the other patient showed the same changes and EEG sleep spindles were absent by two years.

Early stages of the Rett syndrome and infantile neuronal ceroid lipofuscinosis--a difficult differential diagnosis

The Rett syndrome (RS) and infantile neuronal ceroid lipofuscinosis (INCL) are known clinically to present with quite similar manifestations in the very first stages of disease. Ten girls, born 1982-85, from the Swedish series of RS, were compared with 6 children with biopsy-confirmed INCL, deriving from 4 families, as to neurodevelopmental, neurological, ophthalmological, neurophysiological, and CT data. The rapid regression at 1-2 years of age with loss of acquired fine motor skill, learned words, and communication were found to be inseparable between the diseases, as were the successively developing hand and finger stereotypies. Early clues for differential diagnosis were the appearance of transient drop spells, loss of head control, and irregular myoclonias in INCL, flattening of the EEG, early cortical atrophy indicated at CT, and particularly abnormal ERGs. For accurate diagnosis of INCL a biopsy with characteristic EM findings of "snowball" aggregates is a necessity. After 2 3/4-3 years of age, a clinical differentiation was possible in all cases, with visual failure and rapidly decreasing motor ability, head control deterioration, hyperexcitability, and trunk-limb extension tonus being characteristic for INCL.

The infant with nystagmus, normal appearing fundi, but an abnormal ERG

Many retinal disorders present during infancy with nystagmus, decreased vision, and normal-appearing fundi, but an abnormal ERG. The most common of these disorders are Leber's congenital amaurosis, achromatopsia, and congenital stationary night-blindness. Other disorders with similar ocular manifestations may be associated with a variety of life-threatening systemic abnormalities. This review describes the clinical, electrophysiological, and laboratory findings that can be used to distinguish among these conditions.

Follow-up and diagnostic reappraisal of 75 patients with Leber's congenital amaurosis

We reexamined 75 children in whom Leber's congenital amaurosis had been previously diagnosed. On review, 30 of these patients had an ocular or systemic disorder other than Leber's congenital amaurosis. The most common of these revised diagnoses were congenital stationary night blindness, achromatopsia, infantile-onset retinitis pigmentosa, Joubert's syndrome, Zellweger syndrome, and infantile Refsum's disease. Of the 45 patients with Leber's congenital amaurosis, mental retardation occurred in six patients, and visual deterioration in six patients. Leber's congenital amaurosis should only be diagnosed if other known ocular and systemic disorders have been carefully excluded.

Leber's congenital amaurosis--a new syndrome with a cardiomyopathy

Seven members of four families had nystagmus noted by 4 months of age, poor vision, photophobia, and a markedly reduced or absent electroretinogram. Six of these patients had a life threatening episode of cardiac failure in infancy. There were also two neonatal deaths, and one of the affected children died at 2 years and one at 19 years. The five surviving children are well, remain with nystagmus, and have visual acuities of less than 6/60, with the eldest two having lost perception of light. They have a short obese habitus distinct from that of their unaffected siblings and parents.

Neuronal ceroid-lipofuscinoses in childhood

Neuronal Childhood types of ceroid-lipofuscinoses (NCL) are reviewed. All three main types, infantile, late infantile and juvenile, are progressive encephalopathies characterized by neural and extraneural accumulation of ceroid- and lipofuscin like storage cytosomes. The pathogenesis of NCL is unknown. A disturbance of the peroxidation of polyunsaturated fatty acids and a defect in the processing and turn-over of the glycoproteins in the lysosomal membrane are those hypotheses which have been most widely investigated. Reduced membrane lipids and reduced membrane fluidity have recently been detected. Prenatal diagnosis, based on the characteristic ultrastructural findings, is possible in all types.

Neuronal ceroid lipofuscinosis. Ocular histopathologic and electron microscopic studies in the late infantile, juvenile, and adult forms

Diagnosis of the neuronal ceroid lipofuscinoses (NCLF), a group of recessively inherited neurolipidoses, must rely on clinical as well as light and electron microscopic histopathologic findings, as a precise biochemical defect has not yet been identified. We have studied the eyes from two patients with the late infantile and juvenile forms of the disease. On electron microscopy, we observed, almost exclusively, inclusions with curvilinear profiles in the late infantile type, while multimembranous and curvilinear bodies were seen in juvenile NCLF. In both forms of the disease, retinal destruction seems to start at the photoreceptor and outer retinal levels and progresses from the macular area to the periphery. Conjunctival biopsy is helpful in the diagnosis of these disorders, as demonstrated in the adult case presented here.

Ocular features of the Hagberg-Santavuori syndrome

The Hagberg-Santavuori syndrome, the infantile form of the lipopigment storage disorders (so-called neuronal ceroid-lipofuscinoses), is a rare autosomal recessive disease characterized by progressive mental and motor deterioration with an onset between 1 and 1 1/2 years of age. Visual impairment is usually evident early in the disease and hypopigmented retinal degeneration has been described. We studied two unrelated patients with the infantile Hagberg-Santavuori form and found stellate posterior polar cataracts and retinal degeneration with hyperpigmented "bone spicules" in both.

Leber's congenital amaurosis associated with hyperthreoninemia

Two siblings had Leber's congenital amaurosis. The girl (Patient 1) showed blindness shortly after birth, absent pupillary light reflex, and multiple round, white spots in both fundi. Her serum threonine level was increased (2.0 to 5.3 mg/dl; normal, 0.78 to 1.82 mg/dl). She died of massive pericardial effusion four months after birth. Her brother (Patient 2) was nearly blind shortly after birth. He had a poor pupillary light reflex and a nearly extinguished electroretinographic response. He also had hyperthreoninemia, hyperthreoninuria, hepatomegaly, and mental and physical retardation. We suspect a close relationship between hyperthreoninemia and Leber's congenital amaurosis in these siblings.

Neuronal ceroid lipofuscinosis. Diagnosis from peripheral blood smear

Neuronal ceroid lipofuscinosis (NCL), or Batten-Vogt's disease, is a disorder of young children who manifest visual, neurologic, and mental problems. The ophthalmologist can provide helpful diagnostic information by examining the fundus and performing an electroretinogram. In addition, diagnostic markers can be identified by examining circulating lymphocytes from a peripheral blood specimen with light and electron microscopy.

Ceroid lipofuscinosis

Seven of ten patients with ceroid lipofuscinosis, including infantile, late infantile, juvenile, and atypical variants, presented with visual acuity loss. In the infantile case visual acuity loss was early and severe. Two patients with atypical variants did not develop ocular abnormalities. Children presenting with macular degeneration may have more extensive retinal involvement on electrophysiologic testing; neurologic evaluation may rule out the prodromal stages of lipofuscinosis.