Sudden unexpected death in infants (SUDI) is a traumatic event for families, and unfortunately its occurrence remains high in many parts of the world. Whilst cause of death is resolved for most cases, others remain undetermined following postmortem investigations. There has been a recognition of the role of genetic testing in unexplained cases, where previous studies have demonstrated the resolution of cases through DNA analyses. Here we present two case reports of SUDI cases admitted to Salt River Mortuary, South Africa, and show that underlying causes of death were determined for both infants using clinical exome sequencing. The first infant was heterozygous for a variant (rs148175795) in COL6A3, which suggested a bronchopulmonary dysplasia phenotype. This hypothesis led to finding of a second candidate variant in DMP1 (rs142880465), which may contribute towards a digenic/polygenic mechanism of a more severe phenotype. Histological analysis of retained tissue sections showed an asphyxial mechanism of death, where bronchiolar muscle weakness from an underlying bronchopulmonary dysplasia may have contributed to the asphyxia by affecting respiration. In the second infant, a homozygous variant (rs201340753) was identified in MASP1, which was heterozygous in each parent, highlighting the value of including parental DNA in genetic studies. Whilst mannose-binding lectin deficiency could not be assessed, it is plausible that this variant may have acted in combination with other risk factors within the triple-risk model to result in sudden death. These results may have genetic implications for family members, and represent possible new candidate variants for molecular autopsies.

Sudden unexpected death in infants (SUDI) is a devastating event, and unfortunately is still a burden in many parts of the world, including in South Africa. Due to the absence of routine testing for inborn metabolic diseases in newborns and in a post-mortem context, little is known about the presence of metabolic diseases in local SUDI cases. The aim of this study was to genotype five candidate variants previously associated with metabolic disorders in a cohort of SUDI cases (n = 169) from Salt River Mortuary, Cape Town. DNA was isolated from blood, and SNaPshot® PCR and Sanger sequencing were used to genotype the following variants: ACADM: c.583G > A, ACADM: c.985A > G, GCDH: c.877G > A/T, GALT: c.404C > G/T and GALT: c.563A > G. Four carriers of GCDH: c.877G > A/T were identified, while one infant was homozygous for the founder mutation GALT: c.404C > G/T; the latter which is causative of galactosaemia and was previously undiagnosed. During the follow-up with the family, it emerged that the affected infant\'s identical twin had subsequently demised. The findings in this study highlight possible new candidate variants to assess in South African SUDI cases, and these results directly contribute to the development of a molecular autopsy which is locally relevant. It is evident that until newborn screening becomes routine and accessible in South Africa, molecular autopsies should include testing for inherited metabolic disorders, as it holds potential to save lives.

A 34-year-old man, who was previously fit and healthy, died suddenly on exercise. A post-mortem exam performed by forensic pathologists and a toxicological screening were normal; therefore, the cause of death was suspected to be sudden arrhythmic death syndrome, prompting the need for a molecular autopsy. Screening for genetic variations underlying arrhythmogenic genes by next-generation sequencing highlighted a heterozygous single-nucleotide variant in the exon n. 94 of the ryanodine receptor type 2 gene. This gene, encoding the cardiac ryanodine receptor, is one of the main genetic variants of catecholaminergic polymorphic ventricular tachycardia, estimated to affect 1 in 10,000 individuals. It manifests with syncope, seizures, or sudden death due to exercise- or emotional stress-induced bidirectional or polymorphic ventricular tachycardia, usually in children and young adults with morphologically normal hearts and normal baseline electrocardiograms. Even if this de novo missense mutation has not yet been associated with catecholaminergic polymorphic ventricular tachycardia, it is likely to be a disease-causing variant which leads to a defective protein responsible for disturbed ion flow.

Hypertrophic cardiomyopathy (HCM) is a genetic cardiomyopathy with a prevalence of about 1:200. It is characterized by left ventricular hypertrophy, diastolic dysfunction and interstitial fibrosis; HCM might lead to sudden cardiac death (SCD) especially in the young. Due to low autopsy frequencies of sudden unexplained deaths (SUD) the true prevalence of SCD and especially of HCM among SUD remains unclear. Even in cases of proven SCD genetic testing is not a routine procedure precluding appropriate risk stratification and counseling of relatives.
Here we report a case of SCD in a 19-year-old investigated by combined forensic and molecular autopsy.
During autopsy of the index-patient HCM was detected. As no other possible cause of death could be uncovered by forensic autopsy the event was classified as SCD. Molecular autopsy identified two (probably) pathogenic genetic variants in FHL1 and MYBPC3. The MYBPC3 variant had an incomplete penetrance. The FHL1 variant was a de novo mutation. We detected reduced FHL1 mRNA levels and no FHL1 protein in muscle samples suggesting nonsense-mediated mRNA decay and/or degradation of the truncated protein in the SCD victim revealing a plausible disease mechanism.
The identification of the genetic cause of the SCD contributed to the rational counseling of the relatives and risk assessment within the family. Furthermore our study revealed evidences for the pathomechanism of FHL1 mutations.

Vertebral artery laceration/dissection (VALD) resulting in fatal subarachnoid hemorrhage (SAH) is a rare, but well-known phenomenon encountered in the forensic setting. Delayed ruptures are exceptionally rare, and pose several challenges to the forensic pathologist. In this paper we present a case of a 47-year-old male who collapsed suddenly following recent complaints of a headache and a reported seizure. He had a reported history of potential head trauma that occurred several days prior. Attempts at resuscitation were unsuccessful, and an autopsy examination was ordered. Computer tomography (CT), autopsy, histological and ancillary studies were performed. External examination showed mild, healing trauma to the head and upper limbs, and pre-autopsy CT demonstrated a SAH. Examination of the brain showed basally oriented SAH, and there was a laceration of the left vertebral artery. Histological examination demonstrated a delayed rupture, and there was no significant blood vessel abnormality. Molecular testing was negative for collagen vascular disorders. Delayed rupture of the vertebral arteries following head trauma is rare. The presence of remote and/or mild trauma may be difficult to establish at autopsy, and it is important to identify underlying aortopathies. Several autopsy techniques and ancillary studies should be performed in these cases.