Editor—Definition of the clinical and genetic features of multiple congenital anomalies/mental retardation syndromes is a difficult task that requires identification of a specific phenotype in multiple patients in the general population and within families.

We report two sibs possibly affected by a rare MCA/MR syndrome, first observed by Hall and Riggs1 in 1975. No other cases have been published since then.2

Case 1 is an 11½ year old female, the first born to healthy, non-consanguineous parents. Her younger male sib is case 2 of this report. She was the term product of a pregnancy complicated by threatened abortion during the first months and by intrauterine growth retardation. Birth weight was 2400 g, length 46 cm, and OFC 31 cm (all below the 3rd centile). Apgar scores were 7 and 9.

She has had feeding problems, failure to thrive, and severe developmental retardation. She walked unassisted at 6 years and she never achieved any language. Metabolic analysis, including amino acidaemia, amino aciduria, MPS screening, and lysosomal and peroxisomal enzymes has been negative.

Sialotransferrin, cholesterol, and 7-dehydrocholesterol were within normal limits. The EEG showed moderate multifocal irritative anomalies, without evidence of clinical seizures. MRI of the brain showed the presence …