Phosphomannomutase deficiency (PMM2-CDG): ataxia and cerebellar assessment.

BACKGROUND: Phosphomannomutase deficiency (PMM2-CDG) is the most frequent congenital disorder of glycosylation. The cerebellum is nearly always affected in PMM2-CDG patients, a cerebellar atrophy progression is observed, and cerebellar dysfunction is their main daily functional limitation. Different therapeutic agents are under development, and clinical evaluation of drug candidates will require a standardized score of cerebellar dysfunction. We aim to assess the validity of the International Cooperative Ataxia Rating Scale (ICARS) in children and adolescents with genetically confirmed PMM2-CDG deficiency. We compare ICARS results with the Nijmegen Pediatric CDG Rating Scale (NPCRS), neuroimaging, intelligence quotient (IQ) and molecular data. METHODS: Our observational study included 13 PMM2-CDG patients and 21 control subjects. Ethical permissions and informed consents were obtained. Three independent child neurologists rated PMM2-CDG patients and control subjects using the ICARS. A single clinician administered the NPCRS. All patients underwent brain MRI, and the relative diameter of the midsagittal vermis was measured. Psychometric evaluations were available in six patients. The Mann-Whitney U test was used to compare ICARS between patients and controls. To evaluate inter-observer agreement in patients' ICARS ratings, intraclass correlation coefficients (ICC) were calculated. ICARS internal consistency was evaluated using Cronbach's alpha. Spearman's rank correlation coefficient test was used to correlate ICARS with NPCRS, midsagittal vermis relative diameter and IQ. RESULTS: ICARS and ICARS subscores differed between patients and controls (p < 0.001). Interobserver agreement of ICARS was "almost perfect" (ICC = 0.99), with a "good" internal reliability (Cronbach's alpha = 0.72). ICARS was significantly correlated with the total NPCRS score (rs 0.90, p < 0.001). However, there was no agreement regarding categories of severity. Regarding neuroimaging, inverse correlations between ICARS and midsagittal vermis relative diameter (rs -0.85, p = 0.003) and IQ (rs -0.94, p = 0.005) were found. Patients bearing p.E93A, p.C241S or p.R162W mutations presented a milder phenotype. CONCLUSIONS: ICARS is a reliable instrument for assessment of PMM2-CDG patients, without significant inter-rater variability. Despite our limited sample size, the results show a good correlation between functional cerebellar assessment, IQ and neuroimaging. For the first a correlation between ICARS, neuroimaging and IQ in PMM2-CDG patients has been demonstrated.

[Developmental amnesia as a focal cognitive sequela of a neonatal pathology]. / Amnesia del desarrollo como secuela cognitiva focal de patologia neonatal.

INTRODUCTION: The developmental amnesia is a recently known entity that occurs as a consequence of hypoxic-ischemic events in the perinatal period. This is a specific deficit of episodic memory with greater preservation of semantic memory and other memory components such as the immediate and working memory. It occurs in patients without apparent neurological sequelae, with normal psychomotor development and general intelligence. The developmental amnesia has been associated with bilateral involvement of the hippocampus, which is evident in some cases on magnetic resonance imaging (MRI) as signal disturbance and signs of atrophy, or reduced size of the hippocampus in brain volumetric studies. PATIENTS AND METHODS: We present six observations of developmental amnesia, their clinical, neuropsychological and neuroimaging findings. RESULTS: All of them show impaired episodic memory with preservation of semantic memory, have a normal general intelligence and follow a regular school with special educational needs. CONCLUSIONS: It is necessary to keep in mind this entity in monitoring risk newborns by their perinatal history and include the exploration of memory in neuropsychological study of these subjects. On the other hand, we highlight the specificity of the clinical and neuropsychological profile for the diagnosis of developmental amnesia even in the absence of hippocampal lesions on conventional MRI.

Cognitive functions in classic phenylketonuria and mild hyperphenylalaninaemia: experience in a paediatric population.

A study of 37 individuals with phenylketonuria (PKU; 17 females and 20 males, mean age 9y 9mo (standard deviation [SD] 5y 3mo), range 2y 8mo to 19y 4mo; and 35 individuals with hyperphenylalaninaemia (HPA; 20 females, 15 males, mean age 7y 10mo [SD 3y 2mo], range 2y 8mo to 17y 3mo) compared with 29 healthy controls (14 females and 15 males, mean age 9y 8mo [SD 4y 9mo], range 2y 6mo to 18y 10mo) was performed. The aim was to assess cognitive function in persons with HPA and to investigate the relation between cognitive function in PKU and the metabolic control of patients. A wide variety of neuropsychological tests was employed. Those with PKU showed lower values in intelligence and in visuo-spatial, fine motor, executive, and attention functions when compared with a control population. Plasma phenylalanine values from the first 6 years of life were negatively associated with intelligence and other cognitive functions. Executive function scores were significantly lower when comparing HPA patients with the control group. It was concluded that individuals with PKU under dietary treatment may present slightly decreased cognitive function scores when compared with control individuals, while those with HPA have scores mostly similar to those of controls, except for executive function tests. Good metabolic control of PKU seems necessary to prevent cognitive function impairments, especially during the first 6 years of life.

Infectious acute hemicerebellitis.

We report the case of a 5-year-old girl with initial symptoms of encephalitis who presented 24 hours later with hemiataxia, unilateral dysmetria, and hemiparesis. Brain magnetic resonance image (MRI) revealed a high T2-weighted signal in the ipsilateral hemicerebellar cortex. Forty-five days later, a second MRI disclosed signs of hemiatrophy and cortical gliosis. The clinical outcome was favorable, with only a slight lack of motor coordination in the involved hand remaining. Three other cases of hemicerebellitis have been reported in the literature, two of them presenting with hemicerebellar symptoms and one mimicking a tumor. Follow-up imaging studies some months later have shown hemiatrophy of the cerebellar cortex, except in one case with a normal control MRI. The pathophysiology of this unilateral involvement is difficult to explain. We underline the need to consider this rare entity in asymmetric cerebellar clinical presentations and to perform MRI rather than computed tomography to reach the correct diagnosis.