Genetics of Parkinson's disease in Brazil: a systematic review of monogenic forms.

BACKGROUND: Increasing numbers of mutations causing monogenic forms of Parkinson's disease (PD) have been described, mostly among patients in Europe and North America. Since genetic architecture varies between different populations, studying the specific genetic profile of Brazilian patients is essential for improving genetic counseling and for selecting patients for clinical trials. OBJECTIVE: We conducted a systematic review to identify genetic studies on Brazilian patients and to set a background for future studies on monogenic forms of PD in Brazil. METHODS: We searched MEDLINE, EMBASE and Web of Science from inception to December 2019 using terms for "Parkinson's disease", "genetics" and "Brazil". Two independent reviewers extracted the data. For the genes LRRK2 and PRKN, the estimated prevalence was calculated for each study, and a meta-analysis was performed. RESULTS: A total of 32 studies were included, comprising 94 Brazilian patients with PD with a causative mutation, identified from among 2,872 screened patients (3.2%). PRKN mutations were causative of PD in 48 patients out of 576 (8.3%). LRRK2 mutations were identified in 40 out of 1,556 patients (2.5%), and p.G2019S was the most common mutation (2.2%). CONCLUSIONS: PRKN is the most common autosomal recessive cause of PD, and LRRK2 is the most common autosomal dominant form. We observed that there was a lack of robust epidemiological studies on PD genetics in Brazil and, especially, that the diversity of Brazil's population had not been considered.

Peroneal nerve palsy due to compartment syndrome after facial plastic surgery.

A 25-year-old white man, right after bilateral rhytidoplasty, presented with agitation, necessitating use of haloperidol. Some hours after, he developed severe pain in his legs and a diagnosis of neuroleptic malignant syndrome (NMS) was considered. Even with treatment for NMS he still complained of pain. A diagnosis of lower limb compartment syndrome (CS) was done only 12 hours after the initial event, being submitted to fasciotomy in both legs, disclosing very pale muscles, due to previous ischemia. This syndrome was not explained only by facial surgery, his position and duration of the procedure. It can be explained by a sequence of events. He had a history of pain in his legs during physical exercises, usually seen in chronic compartment syndrome. He used to take anabolizant and venlafaxine, not previously related, and the agitation could be related to serotoninergic syndrome caused by interaction between venlafaxine and haloperidol. Rhabdomyolysis could lead to oedema and ischemia in both anterior leg compartment. This report highlights the importance of early diagnosis of compartment syndrome, otherwise, even after fasciotomy, a permanent disability secondary to peripheral nerve compression could occur.

Peroneal nerve palsy due to compartment syndrome after facial plastic surgery

A 25-year-old white man, right after bilateral rhytidoplasty, presented with agitation, necessiting use of haloperidol. Some hours after, he developed severe pain in his legs and a diagnosis of neuroleptic malignant syndrome (NMS) was considered. Even with treatment for NMS he still complained of pain. A diagnosis of lower limb compartment syndrome (CS) was done only 12 hours after the initial event, being submitted to fasciotomy in both legs, disclosing very pale muscles, due to previous ischemia. This syndrome was not explained only by facial surgery, his position and duration of the procedure. It can be explained by a sequence of events. He had a history of pain in his legs during physical exercises, usually seen in chronic compartment syndrome. He used to take anabolizant and venlafaxine, not previously related, and the agitation could be related to serotoninergic syndrome caused by interaction between venlafaxine and haloperidol. Rhabdomyolisis could lead to oedema and ischmemia in both anterior leg compartment. This report highlights the importance of early diagnosis of compartment syndrome, otherwise, even after fasciotomy, a permanent disability secondary to peripheral nerve compression could occur.

Logo após ritidoplastia bilateral, um jovem de 25 anos apresentou agitação, necessitando uso de haloperidol. Algumas horas após, desenvolveu dor intensa em membros inferiores, e o diagnóstico de síndrome neuroléptica maligna foi considerado. Mesmo com o tratamento para tal, persistiu com dor. Após 12 horas do início do quadro, foi realizado o diagnóstico de síndrome compartimental de membros inferiores e o jovem foi submetido a fasciotomia bilateral. Uma seqüência de eventos desencadeou esta síndrome, já que sua ocorrência dificilmente seria justificada pela cirurgia facial e/ou posição do paciente durante o procedimento. O jovem apresentava previamente dor em membros inferiores aos exercícios, sugerindo a ocorrência de uma síndrome compartimental crônica. Ele fazia uso de anabolizantes e venlafaxina, não relatado no início do quadro, e a agitação poderia ser explicada por uma síndrome serotoninérgia desencadeada pela interação deste último medicamento e haloperidol. A rabdomiólise secundária a estes eventos causou edema e isquemia nos compartimentos anteriores de ambos os membros inferiores, levando a uma compressão secundária do nervo fibular. O caso em questão ilustra a importância do diagnóstico precoce da síndrome compartimental pois, caso contrário, mesmo com fasciotomia, uma complicação permanente devido à compressão de nervos periféricos pode se estabelecer.