Clinicogenetic lessons from 370 patients with autosomal recessive limb-girdle muscular dystrophy.

Limb-girdle muscular dystrophies (LGMD) are a group of genetically heterogeneous disorders characterized by predominantly proximal muscle weakness. We aimed to characterize epidemiological, clinical and molecular data of patients with autosomal recessive LGMD2/LGMD-R in Brazil. A multicenter historical cohort study was performed at 13 centers, in which index cases and their affected relatives' data from consecutive families with genetic or pathological diagnosis of LGMD2/LGMD-R were reviewed from July 2017 to August 2018. Survival curves to major handicap for LGMD2A/LGMD-R1-calpain3-related, LGMD2B/LGMD-R2-dysferlin-related and sarcoglycanopathies were built and progressions according to sex and genotype were estimated. In 370 patients (305 families) with LGMD2/LGMD-R, most frequent subtypes were LGMD2A/LGMD-R1-calpain3-related and LGMD2B/LGMD-R2-dysferlin-related, each representing around 30% of families. Sarcoglycanopathies were the most frequent childhood-onset subtype, representing 21% of families. Five percent of families had LGMD2G/LGMD-R7-telethonin-related, an ultra-rare subtype worldwide. Females with LGMD2B/LGMD-R2-dysferlin-related had less severe progression to handicap than males and LGMD2A/LGMD-R1-calpain3-related patients with truncating variants had earlier disease onset and more severe progression to handicap than patients without truncating variants. We have provided paramount epidemiological data of LGMD2/LGMD-R in Brazil that might help on differential diagnosis, better patient care and guiding future collaborative clinical trials and natural history studies in the field.

Newborn Screening for the Detection of the TP53 R337H Variant and Surveillance for Early Diagnosis of Pediatric Adrenocortical Tumors: Lessons Learned and Way Forward.

The incidence of pediatric adrenocortical tumors (ACT) is high in southern Brazil due to the founder TP53 R337H variant. Neonatal screening/surveillance (NSS) for this variant resulted in early ACT detection and improved outcomes. The medical records of children with ACT who did not participate in newborn screening (non-NSS) were reviewed (2012-2018). We compared known prognostic factors between the NSS and non-NSS cohorts and estimated surveillance and treatment costs. Of the 16 non-NSS children with ACT carrying the R337H variant, the disease stages I, II, III, and IV were observed in five, five, one, and five children, respectively. The tumor weight ranged from 22 to 608 g. The 11 NSS children with ACT all had disease stage I and were alive. The median tumor weight, age of diagnosis, and interval between symptoms and diagnosis were 21 g, 1.9 years, and two weeks, respectively, for the NSS cohort and 210 g, 5.2 years, and 15 weeks, respectively, for the non-NSS cohort. The estimated surveillance/screening cost per year of life saved is US$623/patient. NSS is critical for improving the outcome of pediatric ACT in this region. Hence, we strongly advocate for the inclusion of R337H in the state-mandated universal screening and surveillance.