Pontocerebellar Hypoplasia: Literature Review and Clinical Study

1. AbstractPontocerebellar Hypoplasia (PCH) refers to a group of rare, progressive, and hereditary neurodegenerative disorders with prenatal onset. Different subtypes have been identified based on the mutations present, and all share common characteristics, such as severe cognitive, linguistic, and motor disabilities. The objective of this study was to conduct a literature review and describe the clinical case of a 79-month-old boy diagnosed with PCH in terms of cognitive, motor, communicative, and linguistic skills. We also report the implications of the results on the therapeutic process and family homeostasis, as well as our reflections on the matter. Four articles that met the inclusion criteria set by the study were added to the review. The results of the psychological and speech therapy assessment indicate intellectual disability, severe language disorder, and dysarthric speech. Knowledge regarding the severity of these cases and the implications for the family of afflicted individuals when the clinical prognosis is uncertain, can contribute to the therapeutic process.

3. IntroductionPontocerebellar hypoplasia (PCH) refers to a group of progressive, severe, and rare neurodegenerative disorders with prenatal onset that affect the development and function of the brainstem and cerebellum, resulting in developmental disorders [1-3]. It is a genetically heterogeneous autosomal recessive condition [4-7]. PCH is a purely descriptive term that implies a reduced volume of the bridge and cerebellum [5]. As of January 2020, 13 PCH subtypes have been recorded in the OMIM Portal [5]. The incidence rate of each subtype is unknown [6, 7]. The disorder has only symptomatic treatment available and has a poor prognosis. Additionally, life expectancy is difficult to determine, since death can occur at any point of development. Typically, however, patients die in late childhood or adolescence, according to most of the cases mentioned, although there is a possibility of survival until adulthood [6]. Descrições neurorradiológicas e genéticas são encontradas na literatura [1-14], porém com poucas informações sobre a evolução desses casos em relação ao neurodesenvolvimento e aprendizado. Some studies report severe changes in motor development, microcephaly, motor and cognitive disorders [2, 5-9]. Despite the existence of descriptions of signs and symptoms in these areas, there are limited data available on the characterization of the development of the patient. Additionally, currently no studies present the phenotypic profiles of the disorder in terms of global development and communication. The families of patients with rare and severe disorders deal with the uncertainties of the future and the poor prognoses, which can cause additional suffering and difficulties in adhering to the therapeutic process [15]. In view of the above, the objective of this study was to conduct a literature review and describe the clinical case of a 79-month-old boy diagnosed with PCH, particularly in terms of cognitive, motor, communicative, and linguistic skills, as well as to report the implications of the results on the therapeutic process, as well as on family homeostasis.

4. Materials and MethodsTwo bibliographic searches were carried out to find studies describing developmental skills and/or phenotypic profiles of cognitive, motor, communicative, and linguistic skills in individuals with PCH. The searches were performed in national and international databases: Lilacs, PubMed, Scopus, Scielo, Web of Science, and EMBASE. The descriptors were selected after consulting the Health Sciences Descriptors (DeCS-BVS). The survey period covers 2000-2020. The descriptors were as follows: pontocerebellar hypoplasia OR cerebellar hypoplasia, AND (Language OR Cognition OR Cognition Disorders OR Speech OR Language Development Disorders OR Language Disorders OR Language Tests OR Language Therapy OR Rehabilitation of Speech and Language Disorders OR Speech-Language Pathology OR Speech Disorders OR Language Development) OR ("Language"[Mesh]) OR ("Cognition"[Mesh] OR "Cognition Disorders"[Mesh])) OR "Speech"[Mesh]) OR "Language Development Disorders"[Mesh]) OR "Language Disorders"[Mesh]) OR "Language Tests"[Mesh]) OR "Language Therapy"[Mesh]) OR "Rehabilitation of Speech and Language Disorders"[Mesh]) OR "Speech-Language Pathology"[Mesh]) OR "Speech Disorders"[Mesh]) OR "Language Development"[Mesh])) OR Communicative aspect) OR disorders communication) OR Development of communication). The inclusion criteria were derived from articles describing neurodevelopmental skills and evolution in the areas of cognition, language, and communication. On the other hand, the exclusion criteria were taken from review articles describing genetic and/or medical aspects without pointing out the evolution in the areas of cognition, motor, language, and communication.

5. Description of the Clinical CaseEthical procedures were followed (CAE: 42356815.1.0000.5417) and the legal guardian signed a Free and Informed Consent Form. The patient was male with a chronological age of 79 months, diagnosed with PCH, and born to non-consanguineous parents. The mother reported a planned pregnancy, with prenatal care and no complications. The patient underwent full-term birth, via cesarean delivery, at the 39th gestational week. He was born with a weight of 3,835 grams, a height of 51 cm, an Apgar score of 9/10 in the 1st and 5th minutes, and a head circumference of 33 cm. During early childhood, in addition to weak sucking, the baby had difficulty gaining weight and cried a lot. He was not breastfed, but instead fed from a bottle, from birth to three years of age. Considering neuropsychomotor development, he presented cervical balance at 8 months, sat with support at 12 months, sat without support at 18 months, and grabbed objects, stood up, and took his first steps with support at the age of 2 years. He started marching independently at the age of 3, with a history of constant falls and difficulties in balancing that persists until the present. In terms of communication skills, the patient did not produce sounds and did not smile. His first words occurred at around the age of 5, when he started gaining the ability to control sphincters. He underwent physiotherapy and speech therapy at 8 and 36 months, respectively. Additionally, up until the present, he needs help for all activities of daily living. To control attention and behavior, 1.5 ml of risperidone, divided in three doses, is being administered used daily since he was 63 months old. At the age of 3, he also underwent imaging tests and the initial results were indicative of cerebellar dot hypoplasia. The neurologist's report pointed out “global developmental delay associated with According to information provided by the family, as well as through clinical observations, he used gestures to be understood, pointed to the things he wanted, and produced simple words and phrases, mostly consisting merely of the subject and verb. He initiated communicative acts, and, to draw attention, touched people. The child attended a regular school at infant level IV. In terms of learning, he needed more explanations to understand things, and he acted more slowly than peers due to instability in his motor coordination, which is associated with learning difficulties (sic). He also underwent therapeutic accompaniment in the areas of psychology, occupational, and speech therapy. Professionals inferred that the difficulties observed in the fragile therapeutic evolution were due to failure in retention of stimulated and trained information, which interfered in the consolidation of learning. The family showed concern over the therapeutic processes since the therapeutic gains were considered insufficient.

6. Evaluation ProcessThe following development assessment procedures were carried out: Language Development Assessment – ADL [16], Development Screening Test DENVER II (Denver II) [17], MacArthur Communicative Development Inventory: First Words and Gestures [18], Nonverbal Intelligence Test (SON-R) [19], Columbia Mental Maturity Test [2], and Pré-WISC [21]. Complementary assessments were made to augment the subtypes in the PCH chart, whose manifestations include hearing loss, visual impairment, and vitamin A and hydroxyvitamin D deficiency. The patient underwent audiological, ophthalmological, and swallowing examinations, as well as complete blood count, all with indices within normative parameters.

7. ResultsA total of 443 articles were found in the search involving the combined descriptors. The results of the analysis with the application of Note: Adapted from: Moher D, Liberati A, Tetzlaff J, Altman DG, PRISMA Group. Preferred reporting items for systematic reviews and meta-analyzes: the PRISMA Statement. PLoS Med. 2015; 6 (7): e1000097. doi: 0.5123 / S1679-49742015000200017 Chart 1 presents the results of the literature review, with the studies that reported information on clinical characteristics

8. Language and CommunicationTable 1 presents the results obtained in the speech and language assessment using the following instruments: ADL: Language Acquisition and Development [16], Denver-II Development Screening

9. DiscussionThe literature review on the subject of Pontocerebellar Hypoplasia (PCH) presents studies mostly related to the neurological, radiological, and genetic evaluation of the condition, generally describing anatomical measurements, mutations [1-10], and general characteristics of the different PCH subtypes [1-13]. Many of these refer to clinical case studies [1, 8-11]. In the present case, the clinical picture and the progression of the symptoms indicate the possibility of PCH11. This suggests the need for a genetic examination; however, the family is yet to accomplish this. Rudnik-Schonebom et al. [2] stated that the differential diagnosis of PCH is a challenge, considering its early onset and unspecific clinical presentations. Rüsch et al. [5] showed that a systematic analysis of images and clinical characteristics could aid in the differential diagnosis. Van Dijk et al. [6] revealed that new genes and phenotypes related to PCH have been described through the use of state-of-the-art sequencing techniques, and that the classification of the types presented in literature is still confusing, given the heterogeneity of the disorder. They reported that there exist several patients with PCH, who do not possess mutations in any of the genes related to PCH. There are clear descriptions regarding the disease progression of the different PCH types in literature [1-12], except for PCH8 and PCH11. According to the articles compiled [1-9], the manifestations in the linguistic and communicative cognitive areas that are commonly reported involve phenotypes associated with cognitive and behavioral changes, in addition to delays in and/or loss of motor skills, as well as difficulties in maintaining therapeutic gains, given the progressive nature of the disorder.

References1. Battini R, D’Arrigo S, Cassandrini D, Guzzetta A, Fiorillo C, Pantaleoni C, e al. Novel Mutations in TSEN54 in Pontocerebellar Hypoplasia Type 2, p. Journal of Child Neurology. 2014: vol (29)4: 520-524.

2. Rudnik-Schonebom S, Barth PG, Zerres K. Pontocerebellar hypoplasia. Am J Med Genet C Semin Med Genet. 2014 Jun;166C (2):173-83.

3. Safronova MM, Barbot C, Pereira JR,Hipoplasias Cerebelosas. Artigo de Revisão.Acta Med Port 2010; 23: 841-852.

4. OMIM: Online Mendelian Inheritance in Man. 2018. Retrieved.

5. Rush CT, Bölsterli BK, Kotter R, Steinfeld R, Boltshauser E. Pontocerebellar Hypoplasia: a Pattern Recognition Approach. Cerebellum. 2020 May 1. 4 [Epub ahead of print].

6. Namavar Y, Barth PG, Poll-The BT, Bass F. Classification, diagnosis and potential mechanisms in pontocerebellar hypoplasia. Orphanet J Rare Dis. 2011 Jul 12; 6:50.

7. Van Dijk T, Baas F, Barth PG, Poll-The BT. What’s new in pontocerebellar hypoplasia? An update on genes and subtypes. Orphanet J Rare Dis. 2018 Jun 15; 13(1): 92.

Rosa DCB .Pontocerebellar Hypoplasia: Literature Review and Clinical Study . Annals of Clinical and Medical Case Reports 2020