Matchmaking facilitates the diagnosis of an autosomal-recessive mitochondrial disease caused by biallelic mutation of the tRNA isopentenyltransferase (TRIT1) gene.

Deleterious variants in the same gene present in two or more families with overlapping clinical features provide convincing evidence of a disease-gene association; this can be a challenge in the study of ultrarare diseases. To facilitate the identification of additional families, several groups have created "matching" platforms. We describe four individuals from three unrelated families "matched" by GeneMatcher and MatchMakerExchange.

Chromosome 1p36.22p36.21 duplications/triplication causes Setleis syndrome (focal facial dermal dysplasia type III).

Focal facial dermal dysplasias (FFDD) are characterized by congenital bitemporal or preauricular atrophic skin lesions, and either autosomal dominant or autosomal recessive inheritance. Setleis syndrome (SS), FFDD type III, is a severe form of FFDD with the ectodermal lesions plus other striking facial features. Autosomal recessive nonsense and frameshift mutations in TWIST2 have been found to cause SS in some but not all individuals.

Clinical comparison of overlapping deletions of 19p13.3.

We present three patients with overlapping interstitial deletions of 19p13.3 identified by high resolution SNP microarray analysis. All three had a similar phenotype characterized by intellectual disability or developmental delay, structural heart abnormalities, large head relative to height and weight or macrocephaly, and minor facial anomalies.

Advancing our understanding of the inheritance and transmission of pectus excavatum.

Pectus excavatum is the most common congenital chest wall abnormality expressed in children, yet its inheritance is poorly understood. Here we present the first comprehensive assessment of the inheritance of this disorder. After evaluating 48 pedigrees and 56 clinical traits of probands and family members, we find strong evidence of autosomal recessive, genetic control for this disorder.

Minimal evidence for a direct involvement of twisted gastrulation homolog 1 (TWSG1) gene in human holoprosencephaly.

Holoprosencephaly (HPE) is the most common disorder of human forebrain and facial development. Presently understood etiologies include both genetic and environmental factors, acting either alone, or more likely, in combination. The majority of patients without overt chromosomal abnormalities or recognizable associated syndromes have unidentified etiologies.