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Muscular dystrophies are a heterogeneous group of neuromuscular disorders with a wide range of the clinical and genetic spectrum. Whole-exome sequencing (WES) has been on the rise to become the usual method of choice for molecular diagnosis in patients presenting with muscular dystrophy or congenital or metabolic myopathy phenotype. Here, we used a panel with 47 genes including not only muscular dystrophy but also myopathy-associated genes that had been used as a first-tier approach. A total of 146 patients who were referred to our clinic with the prediagnosis of muscular dystrophy and/or myopathy were included in the study. Dystrophin gene deletion/duplication was ruled out on the patients with a preliminary diagnosis of Duchenne muscular dystrophy. In this study, the molecular etiology of 67 patients was proved with the gene panel with a diagnostic yield of 46%. Causal variants were identified in 23 genes including CAPN3(11), DYSF(9), DMD(8), SGCA(5), TTN(4), LAMA2(3), LMNA(3), SGCB(3), COL6A1(3), DES (2), CAV3(2), FKRP(2), FKTN(2), ANO5, COL6A2, CLCN1, GNE, POMGNT1, POMGNT2, POMT2, SYNE1, TCAP, and FLNC with 16 novel variants. There were 27 patients with uncertain molecular results including the ones who had a variant of uncertain significance, who had only one heterozygous variant for an autosomal recessive disease, and the ones who had two variants in different genes. Molecular diagnosis in muscular dystrophy is essential to plan clinical management and choosing treatment options. Also, the results will affect the reproduction options. Targeted next-generation sequencing is a cost-effective method that reduces the WES requirements with a significant diagnostic rate.

Introduction: Chromosomal abnormalities are mostly found in 0.5–0.8% of live-born infants with developmental and morphological defects. Paracentric inversions are structural intrachromosomal rearrangements resulting in a risk of chromosomally unbalanced gametes in carriers. Case Presentation: Herein, we report a patient with dicentric rearrangement of chromosome 18 due to maternal paracentric inversion of chromosome 18. The patient was a girl, aged 3 years and 11 months. She was referred due to multiple congenital abnormalities, severe intellectual disability, and motor retardation. She had microcephaly, prominent metopic suture, synophrys, epicanthic folds, telecanthus, wide-set alae nasi, wide columella, bilateral cleft lip and palate, pectus carinatum, umbilical hernia, pes planus, and anteriorly displaced anus. She had bilateral external auditory canal stenosis and mild right-sided and moderate left-sided sensorineural hearing loss. Echocardiography showed secundum-type atrial septal defect and mild tricuspid failure. Brain magnetic resonance imaging showed only thinning of posterior areas of the corpus callosum. Chromosome analysis showed 46,XX,dic rec(18) by GTG and C banding. Dicentric chromosome was confirmed by fluorescence in situ hybridization analysis. Paternal karyotype was normal 46,XY but maternal chromosome analysis showed a paracentric inversion in chromosome 18 with 46,XX,inv(18)(q11.2?q21.3?) karyotype. Array CGH was performed on a peripheral blood sample from the patient and showed duplication at 18p11.32p11.21 and 18q11.1q11.2, and deletion at 18q21.33q23. The patient’s final karyotype is arr 18p11.32p11.21(64,847_15,102,598)×3,18q11.1q11.2(18,542,074_22,666,470)×3,18q21.33q23(59,784,364_78,010,032)×1. Discussion: To the best of our knowledge, this is the first report of a patient with dicentric chromosome 18 due to a parental paracentric inversion of chromosome 18. We present the genotype-phenotype correlation with literature review.

Recombinant chromosome 4 is a very rare chromosomal aberration with eleven cases reported in the literature up to date. Here we report a five years old male patient with de novo rec(4) dup(4p) del(4q). The physical examination findings were as follows: caput quadratum, flat occiput, low frontal hairline, hypertelorism, ptosis, blepharophimosis, high arched eyebrows, flat nasal root with antevert nostrils and short nose, long and smooth philtrum, thin upper lip with triangular mouth, high arched palate, dental anomalies, large low-set ears, short neck, broad chest with widely spaced nipples, micropenis, cryptorchidism. Conventional cytogenetic analysis revealed the karyotype as 46,XY,rec(4)dup(4p14p16.3)del(4q34.3q35). Flourescence in-situ hybridization (FISH) analysis with sub-telomeric probes for 4p and 4q showed duplication of 4p and deletion of 4q in recombinant chromosome 4. His parents’ chromosomal analysis and sub-telomeric FISH analysis were both normal. The patient’s final karyotype was reported as 46,XY,rec(4)dup(4p16.3p14)del(4q34.4q35).arr[hg19]4p16.3p14(68,345-36,018)x3,4q34.3q35(177,676,319-190,957,460)x1 detected by Microarray. According the literature all cases with recombinant chromosome 4 have similar clinical findings. Except for our case only one case in the literature has been reported to be de novo . In conclusion, we reported a very rare case of recombinant chromosome 4, which has the largest deletion and duplication in the literature. Further cases with similar findings would help delineation of the symptoms related to the aberration.

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