Smith-Lemli-Opitz syndrome (SLOS) is a congenital multiple-anomaly / cognitive impairment syndrome caused by an abnormality in cholesterol metabolism resulting from deficiency of the enzyme 7-dehydrocholesterol (7-DHC) reductase. It is characterized by prenatal and postnatal growth restriction, microcephaly, moderate-to-severe intellectual disability, and multiple major and minor malformations. The malformations include distinctive facial features, cleft palate, cardiac defects, underdeveloped external genitalia in males, postaxial polydactyly, and 2-3 syndactyly of the toes. The clinical spectrum is wide; individuals with normal development and only minor malformations have been described.

Thrombocytopenia absent radius (TAR) syndrome is characterized by bilateral absence of the radii with the presence of both thumbs, and thrombocytopenia that is generally transient. Thrombocytopenia may be congenital or may develop within the first few weeks to months of life; in general, thrombocytopenic episodes decrease with age. Cow's milk allergy is common and can be associated with exacerbation of thrombocytopenia. Other anomalies of the skeleton (upper and lower limbs, ribs, and vertebrae), heart, and genitourinary system (renal anomalies and agenesis of uterus, cervix, and upper part of the vagina) can occur.

Intellectual disability-brachydactyly-Pierre Robin syndrome is a rare developmental defect during embryogenesis syndrome characterized by mild to moderate intellectual disability and phsychomotor delay, Robin sequence (incl. severe micrognathia and soft palate cleft) and distinct dysmorphic facial features (e.g. synophris, short palpebral fissures, hypertelorism, small, low-set, and posteriorly angulated ears, bulbous nose, long/flat philtrum, and bow-shaped upper lip). Skeletal anomalies, such as brachydactyly, clinodactyly, small hands and feet, and oral manifestations (e.g. bifid, short tongue, oligodontia) are also associated. Additional features reported include microcephaly, capillary hemangiomas on face and scalp, ventricular septal defect, corneal clouding, nystagmus and profound sensorineural deafness.

Blepharophimosis-intellectual disability syndrome, Verloes type is a rare, genetic multiple congenital anomalies/dysmorphic syndrome characterized by congenital microcephaly, severe epilepsy with hypsarrhythmia, adducted thumbs, abnormal genitalia, and normal thyroid function. Hypotonia, moderate to severe psychomotor delay, and characteristic facial dysmorphism (including round face with prominent cheeks, blepharophimosis, large, bulbous nose with wide alae nasi, posteriorly rotated ears with dysplastic conchae, narrow mouth, cleft palate, and mild micrognathia) are additional characteristic features.

Neurodevelopmental disorder with hypotonia, dysmorphic facies, and skeletal anomalies, with or without seizures (NEDFSS), is characterized by these features and global developmental delay with delayed or absent walking, moderate to severely impaired intellectual development, and poor or absent speech acquisition. Affected individuals may also have behavioral abnormalities. About half of patients develop various types of seizures that are usually well-controlled with medication. Rare patients are noted to have heat intolerance or insensitivity to pain (Lines et al., 2022).