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Título

PELIZAEUS-MERZBACHER DISEASE (PMD) – CASE REPORT

Apresentação do caso

FHTA, male, 12 years old, child of a non-consanguineous couple, history of fetal distress, born at term, Apgar 7/8. Reported nystagmus since birth, difficulty controlling the head and hypotonia, despite maintaining eye contact, recognizing voices and smiling. First evaluation with a Pediatric Neurologist was at 5 months with clinical features of horizontal and vertical nystagmus, head circumference of 43.5 cm, axial hypotonia, poor cervical support, airway clearance without shoulder elevation, strength 4/5 in all four limbs, present, increased and symmetrical deep reflexes and, anthropometric assessment below the P3 percentile, without stagnation. At 12 months on Magnetic Resonance Imaging (MRI), there was a delay in CNS myelination. Neuroimaging was repeated at 3 years and 8 months with the same pattern of hypomyelination. At 4 years old, a molecular test was performed confirming the disease (Pelizaeus Merzbacher Syndrome) by the presence of duplication in the PLP1 gene, which encodes the myelin proteolytic protein, of X-linked recessive inheritance. Patient evolved with delayed developmental milestones, currently walks with some difficulty, short stature and weight, head circumference at the lower limit, mild/moderate intellectual deficit, remains with vertical and horizontal nystagmus and is more dependent for his daily activities than expected.

Discussão

Pelizaeus-Merzbacher disease is a progressive X-linked recessive hypomyelinative leukodystrophy (HLD1) in which myelin is not properly formed in the central nervous system, thus permanently reducing its amount in the body. PLP is a transmembrane protein highly expressed in oligodendrocytes, responsible for myelin compaction and formation of intraperiodic lines of the myelin sheath.
Diseases related to the PLP1 gene mainly comprise the classical (HLD1), connatal (HLD3) and transitional PMD forms.
The patient presented has the classic form, which is characterized by starting in the first year of life, with a slow and progressive course.

Comentários finais

Because it is a rare disease of genetic origin and presents nonspecific and progressive characteristics, the diagnosis must be suspected by the clinic and imaging tests, being confirmed with genetic tests. Treatment is still based on support depending on the needs of each patient, thus, better knowledge of this pathology increases the number of diagnoses and genetic evaluation has relevant implications for the prognosis and genetic counseling of the family.

Referências (se houver)

1- Entry - #312080 - PELIZAEUS-MERZBACHER DISEASE; PMD - OMIM. Disponível em: . Acesso em: 7 ago. 2022.
2- Hobson GM1, Garbern JY. Pelizaeus-Merzbacher disease, pelizaeusMerzbacher-like disease 1,
and related hypomyelinating disorders. Seminars in neurology. 2012 Feb; 32: 62-7.
3- HOFFMAN-ZACHARSKA, D. et al. The spectrum of PLP1 gene mutations in patients with the classical form of the Pelizaeus-Merzbacher disease. Medycyna Wieku Rozwojowego, v. 17, n. 4, p. 293–300, 1 out. 2013.
4- Pizzini F, Fatemi AS, Barker PB, Nagae-Poetscher LM, Horská A, Zimmerman AW et al. Proton MR spectroscopic imaging in Pelizaeus-Merzbacher disease. AJNR Am J Neuroradiol. 2003;24(8):1683-9.

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Declaração de conflito de interesses de TODOS os autores

no conflit of interest were declared