Overall, 8 affected individuals (4 males and 4 females) from 5 unrelated families have been reported so far.
Parents of all affected individuals were consanguineous.
Not surprisingly, all affected individuals were initially suspected to have Prader-Willi syndrome, since the main clinical characteristics of BDV syndrome in early and late childhood overlap with that of Prader-Willi syndrome.
Developmental delay/intellectual disability (ID)
• moderate to severe developmental delay and ID (8/8 individuals)
• severe disorder of receptive and expressive speech (8/8 individuals)
• mild to moderate impairment of gross motor development including coordination problems (8/8 individuals)
• restricted fine motor skills (8/8 individuals)
Behavioral disorders
• behavioral anomalies (3/4 individuals; for the remaining no information was available)
• reported behavioral anomalies: defiant behavior, aggressiveness, stereotypic movements and autism spectrum disorder
Neuromuscular disorders
• mild infantile muscular hypotonia (5/5 individuals; for the remaining no information was available)
Obesity
• severe to morbid obesity (7/8 individuals)
• onset of increased weight gain from 6 months to 4 years
• hyperphagia (6/6 individuals)
Other endocrine disorders
• hypothyroidism (6/7 individuals)
• hypogonadotropic hypogonadism (4/4 individuals, for 2 additional individuals was suspected but not tested)
• amenorrhea (3/4 female individuals) and irregular menstruation (1/4 female individuals)
• hypogenitalism (2/4 individuals)
• cryptorchidism (2/4 individuals)
• insulin resistance (3/8 individuals)
• diabetes mellitus diagnosed at age 19 (1/8 individuals) and suspicion of prediabetes (1/8 individuals)
Other less frequent clinical traits
• enuresis
• hepatic steatosis
• hypercholesterinemia
• hypertriglyceridemia
• hypermetropia
• intermittent exotropia
• joint hypermobility
• brain anomalies
• Pes planus
Recurrent craniofacial anomalies
• coarse facial features (5/8 individuals)
• oval face (6/6 individuals)
• low anterior hairline (4/7 individuals)
• short/narrow palpebral fissures (4/4 individuals)
• low-hanging columella (6/7 individuals)
• cupid bow upper lip (5/6 individuals)
• thin upper lip vermilion (5/8 individuals)
• everted lower lip vermilion (6/7 individuals)
• micrognathia (7/7 individuals)