Intrafamilial Variability of the R694C Variant in BICD2 Presenting with Lethal Severe Arthrogryposis

Arthrogryposis multiplex congenita (AMC) is a heterogeneous condition comprising congenital multiple joint contractures, and it is secondary to decreased fetal mobility following environmental/genetic abnormalities. BICD2 pathogenic variants have been associated with autosomal dominant spinal muscular atrophy with lower extremity predominance (SMALED2). We report the case of a newborn with decreased fetal movements and ventriculomegaly diagnosed in utero, born with severe AMC, multiple bone fractures, congenital hip dislocation, and respiratory insufficiency that led to neonatal death. His mother had AMC diagnosis without established etiology. Her phenotype characterization was key to guide the genetic investigation. A BICD 2 heterozygous variant (NM_001003800.1; c.2080C > T; p. [Arg694Cys]) was detected both in the mother and the newborn. This variant had previously been reported in 3 cases, all having de novo severe SMALED-type 2B (MIM#618291) phenotype. This is the first report of this variant (p. [Arg694Cys]) presenting with an inherited, severe, and lethal phenotype associated to intrafamilial variability, suggesting a more complex phenotype-genotype correlation than previously stated.

Familial Mediterranean fever in the pediatric population

Familial Mediterranean fever (FMF) is the most frequent autoinflammatory disorder characterized by short, repeated, and self-limiting crises of fever and serositis. The disease was described as autosomal recessive hereditary transmission secondary to variants of the MEFV (MEditerranean FeVer) gene, even though a variable proportion of patients only present a heterozygous variant. FMF is very common in certain ethnic groups (Turkish, Armenian, Arab, and Jewish), even though it has been described throughout the Mediterranean and elsewhere in the world. The clinical manifestations are variable, with secondary amyloidosis being the most serious complication of the disorder. Treatment and prophylaxis are mainly based on the administration of colchicine, which prevents the crises and avoids complications in most cases. This study reviews the course of seven pediatric patients diagnosed with FMF during the period 2010–2018 at a district hospital. Most of the patients were of Caucasian origin, with onset at an early age in the form of fever as the main symptom, and some patients moreover presented less frequent manifestations (pericardial effusion, sensorineural hearing loss). Two cases presented plasmatic amyloid A protein elevation that subsided with the treatment. All the patients initially received colchicine, and one of them required prescription of anakinra, which was replaced by canakinumab due to a serious adverse reaction. There were no cases of consanguinity, and all the patients were of Mediterranean origin. The subjects showed a favorable course over the years, which was attributed to the early diagnosis and treatment provided.

New mutation in the TRIP4 gene associated with congenital muscular dystrophy Davignon–Chauveau type (clinical case)

Congenital muscular dystrophies are heterogeneous groups of neuromuscular diseases leading to hypotonia, progressive muscle weakness and dystrophic or structural signs in muscle biopsy. At the present time, 34 genes associated with congenital muscular dystrophy have been described. The clinical case of a rare form of congenital muscular dystrophia associated with a homozygous mutation in the TRIP4 gene in a patient with respiratory failure requiring respiratory support, neurological symptoms, muscular hypotonia, and multiple congenital malformations of skeletal system is presented for the first time in Russia. The undescribed pathogenic homozygous variant of the nucleotide sequence in the TRIP4 gene (chr15:64686179, c.136C>T, p.Arg46Ter, 2 exon, NM_016213.4) was detected by whole exome sequencing. The mutation in the TRIP4 gene was validated by Sanger sequencing in a child and its origin was investigated. The mother and father of the girl are carriers of the heterozygous variant in the TRIP4 gene. Identification of the genetic cause of a rare form of neuromuscular disease is important for determining the tactics of patient management and medical and genetic counseling of the family, as well as clarifying the pathogenesis of a rare pathology.

Expanding the phenotypic spectrum of mutations in LRP2: a novel candidate gene of non-syndromic familial comitant strabismus

Background Comitant strabismus (CS) is a heterogeneous disorder that is a major contributing factor to unilateral childhood-onset visual impairment. Studies have confirmed that genetic factors play an important role in the development of CS. The aim of this study was to identify the genetic cause of non-syndromic familial CS. Methods Fourteen unrelated CS families were recruited for the study. Twelve affected and 2 unaffected individuals from a large four-generation family (CS08) were selected to perform whole genome-wide linkage analysis. Parallel whole-exome sequencing (WES) was conducted in the same family (9 patients and 1 unaffected member) and 31 additional CS cases from 13 other unrelated families. Sanger sequencing was used to determine whether any of the remaining variants co-segregated with the disease phenotype in the corresponding family. Results Based on linkage analysis, CS in family CS08 mapped to a novel region of 34.17 centimorgan (cM) on chromosome 2q22.3-2q32.1 between markers D2S151 and D2S364, with a maximum log odds (LOD) score of 3.54 (theta = 0) at D2S142. Parallel WES identified a heterozygous variant, LRP2 c.335 A > G (p.Q112R), located in such a linkage interval that completely co-segregated with the disease in the family. Furthermore, another novel heterozygous variant (c.7274A > G, p.D2425G) in LRP2 that co-segregated was detected in 2 additional affected individuals from another unrelated family by WES. Both variants are predicted to be damaging by PolyPhen-2, SIFT and MutationTaster, and were absent in 100 ethnically matched normal controls. Conclusion LRP2 is a novel candidate genetic cause of non-syndromic familial CS.

A Novel Mutation (D395A) in Valosin-Containing Protein Gene Is Associated With Early Onset Frontotemporal Dementia in an Italian Family

Inclusion body myopathy (IBM) with Paget’s disease of bone (PDB) and/or frontotemporal dementia (FTD) (IBMPFD) was recently identified as rare autosomal dominant disorder due to mutations in VCP gene. However, VCP mutations have also been documented in patients with amyotrophic lateral sclerosis (ALS), Charcot-Marie-Tooth type 2 (CMT2) disease, and hereditary spastic paraplegia (HSP), underlining the heterogeneity of the phenotypes due to VCP mutations. In this study, we reported a novel missense heterozygous variant c.1184A > C (p.D395A) in exon 10 of VCP gene identified in three patients (two sisters and one brother) belonging to an Italian family. The patients underwent a detailed clinical evaluation including medical history, neurological examination, and neuropsychological assessment. Brain’s morphologic and functional analysis was also performed. The whole picture was consistent with the criteria of behavioral variant frontotemporal dementia (bvFTD) without IBM and PBD. Our report confirms the high degree of heterogeneity of VCP disease. A VCP analysis should be considered for the genetic screening of familial bvFTD with an early onset also in absence of IBM or PDB signs.