Purpose: An investigation for the co-occurrence of two unrelated genetic disorders of muscular dystrophy and Prader-Willi syndrome (PWS) (OMIM#176270) using joint whole genome sequencing (WGS). Methods: Trio WGS joint analysis was performed to investigate the genetic etiology in a proband with PWS, prolonged muscular hypotonia associated hyperCKemia, and early-onset obesity. The parents were unaffected. Results: Results showed maternal isodisomy uniparental disomy (UPD) in chromosome 15, expanding from 15q11.2 to 15q22.2, including PWS regions at 15q11.2–15q13. Maternal heterodisomy was detected from 15q22.2 to 15q26.3. A pathogenic variant, NM_000070.3(CAPN3):c.550del (p.Thr184fs), was identified at 15q15.1 in a heterozygous state in the mother that was homozygous in the proband due to maternal isodisomy. Conclusion: This is the first study of the concurrent molecular etiology of PWS and calpainopathy (OMIM#253600) in the same patient. This report highlights the utility of joint analysis and the need for the assessment of autosomal recessive disease in regions of isodisomy in patients with complex and unexplained phenotypes.

Background: Intellectual developmental disorder with autism and speech delay (IDDAS) is a rare and complex neurological disorder characterized by the presence of both intellectual and speech impairment and features of autism spectrum disorder (ASD). The prevalence of IDDAS is unknown but genetically, it is caused by heterozygous variants in the TBR1 gene. Methods: A 7-year-old female with autistic features and delayed speech development was presented with unaffected parents. Trio-joint analysis was conducted on whole-genome sequencing (WGS) data from the proband and unaffected parents. A phenotype-driven analysis was conducted to investigate variants related to the patient’s clinical presentation. A zygosity-focused analysis was performed to investigate de novo and compound heterozygote variants related to the etiology. Results: The joint-genome analysis identified a novel NM_006593.4(TBR1):c.1303C>T p.Gln435* nonsense variant in the proband. The de novo analysis confirmed the absence of the variant in the parents. No additional causative variants were identified in genes associated with the proband’s phenotype. Conclusions: This is the first report of the NM_006593.4(TBR1):c.1303C>T variant in a patient with IDDAS. This study presents the clinical features of the patient and highlights details of trio-WGS analysis in the molecular diagnosis of this complex disease. Sharing these details is important, as they contribute to the understanding of the spectrum of this rare syndrome.

Smith–Magenis syndrome is a complex neurobehavioral genetic disorder with a broad phenotypic spectrum. While the etiology of SMS is commonly attributed to one-copy interstitial deletion in the 17p11.2 region (90–95% of cases), variants identified by sequence analysis in RAI1 have also been reported in 5–10% of cases. In this study, we report a 9-year-old male with global cognitive and psychomotor developmental delay, musculoskeletal and cardiovascular abnormalities, and dysmorphic craniofacial features. Joint analysis was performed on the whole-genome sequencing data obtained from the proband, unaffected parents, and unaffected brother. This quad analysis identified the novel de novo RAI1:c.2736delC variant. This is the first report of this variant in the literature. This report highlights the details of genome analysis and the patient’s phenotypic spectrum.

Background: The phenotypic spectrum of ANO5 muscle disease ranges widely from elevated creatine kinase (CK) levels in the serum of asymptomatic individuals to progressive muscular dystrophy. Due to overlapping clinical features among muscular dystrophies, the diagnosis of ANO5 muscle disease is established by molecular genetic tests. Early diagnosis is crucial for the clinical management of symptoms and to mitigate cardiac and musculoskeletal complications. Methods: Quad-joint analysis was performed on whole genome sequencing (WGS) data obtained from an 18-year-old female with mild myalgia and elevated CK and her unaffected parents and sister. The phenotype-driven analysis was performed to prioritize genomic alterations related to the phenotype. The zygosity-based analysis investigated compound heterozygous and de novo status for all variants. Results: The quad-joint WGS analysis revealed a novel pathogenic heterozygous variant, ANO5:c.1770_1773del (p.Phe593Metfs*15), that was paternally inherited. A second and known pathogenic heterozygous variant, ANO5:c.148C>T (p.Arg50*), was also present that was maternally inherited. The genome finding led to the diagnosis of autosomal recessive ANO5 muscle disease and an early personalized clinical management for the patient regarding her cardiac and musculoskeletal health. Conclusions: This is the first report of the ANO5:c.1770_1773del variant in the literature. This report highlights the spectrum of ANO5 muscle disease and describes the role of quad-joint WGS in the early diagnosis and preventive clinical management of ANO5 muscle disease.

Goal Kabuki syndrome (KS) is a rare malformation syndrome caused by mutations in KMT2D and KDM6A genes. Besides the cardinal manifestations, including distinctive facial appearance, mild-to-moderate intellectual disability, dermatoglyphic abnormalities such as persistence of fetal fingertip pads, skeletal anomalies and postnatal growth retardation, a wide spectrum of other anomalies is documented so far. We present clinical features and diagnostic findings in our four patients. Methods During the 2016-2019 period, four of our patients were diagnosed with KS based on clinical observation and gene-targeted testing or comprehensive genomic testing (exome sequencing). Results Three of our patients were males, one aged 17 and two aged 3 years, and one female aged 16 years at the time of diagnosis. Mutation of the KMT2D gene was identified in two patients, mutation KDM6A in one patient, while molecular analysis of one male patient is still in progress. In addition to the five cardinal findings, one male patient had cleft palate, one had aortal coarctation with bicuspid aortic valve and one had multiple severe respiratory infections. Although susceptibility to autoimmune disorders is a known feature in these patients, our female patient with KMT2D gene mutation was recognized as the first KS patient with systemic lupus erythematosus. Conclusion KS is a rare disorder with highly variable clinical features making the diagnosis difficult. Consequently, a close collaboration between pediatric subspecialists, clinical geneticists and molecular biologists is essential in the terms of clinical recognition and genetic confirmation of this syndrome.