KLHL7
| PERCHING syndrome (OMIM 617055) | AR | Infants w/PERCHING syndrome may resemble those w/CISS/CS: both disorders are assoc w/paroxysmal oropharyngeal muscle contractions, swallowing & feeding difficulties, typical dysmorphic features, & camptodactyly. 1 Some persons w/PERCHING syndrome have hyperthermia & signs of retinitis pigmentosa. | Unlike CISS/CS, few persons w/PERCHING syndrome survive childhood, & none has demonstrated cold-induced sweating. |
LIFR 2 | Stüve-Wiedemann syndrome (STWS) (OMIM 601559) | AR | Dysmorphic facial features; camptodactyly; severe sucking, swallowing, & feeding difficulties; stimulus-induced abnormal posturing & episodic facial contractions; laryngospasm causing respiratory distress; episodes of hyperthermia & sudden death. 2 Persistent heat intolerance & paradoxic cold-induced sweating. 3 Teens may manifest ↓ pain perception, signs of corneal injuries & scarring, early dental decay, & progressive kyphoscoliosis. | Chondrodysplasia (manifest as congenital bowing of the long bones & ↓ joint mobility) is the main differentiating characteristic. (Note: STWS w/cold-induced sweating but w/o bowing of long bones has been reported. 4) |
MAGEL2
| Schaaf-Yang syndrome (SYS) | AD 5 | Neurodevelopmental disorder similar to Prader-Willi syndrome. Manifest at birth w/generalized hypotonia, sucking & feeding difficulties, episodic severe respiratory distress & sleep apnea, & distal joint contractures. Children show marked DD & speech delay, & exhibit autistic behavior & ID. | Infants w/SYS do not present w/characteristic dysmorphic features, episodic facial contractions, or stimulus-induced posturing typical of CISS/CS. SYS is not assoc w/hyperthermia or impaired thermoregulation. |
MYH3
| Distal arthrogryposis types 2A & 2B (DA2A/DA2B) (OMIM 193700 & 601680) | AD | Severe distal arthrogryposis & joint contractures; "whistling face" (intermittent facial muscle contraction & puckering of lips) that may resemble facial movements in young children w/CISS/CS | In infants w/CISS/CS (but not in DA2A/DA2B), puckering of lips is provoked by crying. In DA2A/DA2B, puckering of lips may occur when resting or sleeping. Microstomia (seen in DA2A/DA2B) is not assoc w/CISS/CS. |
NALCN
| Congenital contractures of the limbs & face, hypotonia, & DD (CLIFAHDD) (OMIM 616266) | AD | Striking similarity w/CISS/CS: facial dysmorphisms, distal arthrogryposis & camptodactyly; micrognathia, impaired sucking, swallowing, & feeding w/need for long-term NG tube feeding; episodic stimulus-induced facial & oropharyngeal contractions, pursing of lips & excessive salivation, inspiratory stridor, & hypoxemia. Spells occur only during waking & incl excessive sweating in face, head, & upper trunk. 7 | Unlike CISS/CS, CLIFAHDD is assoc w/persistent severe axial hypotonia, precarious respiratory status, & DD. |