Hypertrophic cardiomyopathy: a new mutation illustrates the need for family-centered care.

This is a case series of a family positive for a previously undescribed mutation in the myofilament gene MYH7, causing hypertrophic cardiomyopathy (HCM), a potentially lethal cardiac disease with strong hereditability. The family's significant disease became strikingly apparent with the unanticipated diagnosis of their newborn infant shortly after her birth. This led to the discovery of the MYH7 mutation in the infant, as well as her father and two siblings, all of whom had varying degrees of disease severity. Despite prior diagnosis of HCM for the paternal grandmother and great uncles, this family's situation points to the need for continued education of healthcare providers, when heritable diseases are encountered. Genetics consult should occur early and has been shown to be helpful in making an accurate diagnosis and identifying relatives at risk of developing the condition. It may, as in this case series, lead to the discovery of a novel mutation and contribute to the growing genetic database for familial HCM.

Genomics in clinical practice: lessons from the front lines.

The price of whole-genome and -exome sequencing has fallen to the point where these methods can be applied to clinical medicine. Here, we outline the lessons we have learned in converting a sequencing laboratory designed for research into a fully functional clinical program.

Making a definitive diagnosis: successful clinical application of whole exome sequencing in a child with intractable inflammatory bowel disease.

PURPOSE: We report a male child who presented at 15 months with perianal abscesses and proctitis, progressing to transmural pancolitis with colocutaneous fistulae, consistent with a Crohn disease-like illness. The age and severity of the presentation suggested an underlying immune defect; however, despite comprehensive clinical evaluation, we were unable to arrive at a definitive diagnosis, thereby restricting clinical management. METHODS: We sought to identify the causative mutation(s) through exome sequencing to provide the necessary additional information required for clinical management. RESULTS: After sequencing, we identified 16,124 variants. Subsequent analysis identified a novel, hemizygous missense mutation in the X-linked inhibitor of apoptosis gene, substituting a tyrosine for a highly conserved and functionally important cysteine. X-linked inhibitor of apoptosis was not previously associated with Crohn disease but has a central role in the proinflammatory response and bacterial sensing through the NOD signaling pathway. The mutation was confirmed by Sanger sequencing in a licensed clinical laboratory. Functional assays demonstrated an increased susceptibility to activation-induced cell death and defective responsiveness to NOD2 ligands, consistent with loss of normal X-linked inhibitor of apoptosis protein function in apoptosis and NOD2 signaling. CONCLUSIONS: Based on this medical history, genetic and functional data, the child was diagnosed as having an X-linked inhibitor of apoptosis deficiency. Based on this finding, an allogeneic hematopoietic progenitor cell transplant was performed to prevent the development of life-threatening hemophagocytic lymphohistiocytosis, in concordance with the recommended treatment for X-linked inhibitor of apoptosis deficiency. At >42 days posttransplant, the child was able to eat and drink, and there has been no recurrence of gastrointestinal disease, suggesting this mutation also drove the gastrointestinal disease. This report describes the identification of a novel cause of inflammatory bowel disease. Equally importantly, it demonstrates the power of exome sequencing to render a molecular diagnosis in an individual patient in the setting of a novel disease, after all standard diagnoses were exhausted, and illustrates how this technology can be used in a clinical setting.