(concurring, with whom Cordy, J., joins). I agree with the court that, where an employee alleges that he was *39terminated from employment because the employer did not want to be financially responsible under its health plan for the anticipated medical expenses arising from his spouse’s handicap, the employee states a cognizable claim of “associational discrimination” under G. L. c. 151B, § 4 (16), which bars employment discrimination on the basis of handicap. I write separately to emphasize the limited scope of this holding, because I fear that “associational discrimination” might otherwise be interpreted more broadly than the court’s opinion intends.
As the court notes, § 4 (16) makes it an unlawful practice “[f]or any employer ... to dismiss from employment . . . because of his handicap, any person alleging to be a qualified handicapped person, capable of performing the essential functions of the position involved with reasonable accommodation, unless the employer can demonstrate that the accommodations required to be made to the physical or mental limitations of the person would impose an undue hardship to the employer’s business” (emphasis added). This language reflects that the Legislature was focused on prohibiting employment discrimination against a qualified handicapped employee because of the employee’s handicap where the employee with reasonable accommodation is capable of performing the essential functions of the job. The language does not suggest that it was intended to protect an employee from dismissal because of a family member’s handicap, where the employee himself is not handicapped.
I recognize that the interpretation of this language by the Massachusetts Commission Against Discrimination (commission) would typically be entitled to substantial deference, but deference is warranted only where an agency’s interpretation of a statute is reasonable and, ultimately, our review is de novo. See Attorney Gen. v. Commissioner of Ins., 450 Mass. 311, 319 (2008), quoting Commerce Ins. Co. v. Commissioner of Ins., 447 Mass. 478, 481 (2006) (“We review questions of statutory interpretation de novo, . . . giving ‘substantial deference to a reasonable interpretation of a statute by the administrative agency charged with its administration enforcement’ ”). Cf. Goldberg v. Board of Health of Granby, 444 Mass. 627, 632-633 (2005) (where Legislature has “spoken with certainty on the topic in question,” no deference granted to agency regula*40tion interpreting statute). When one looks to the few commission cases that have interpreted § 4 (16) to include associational discrimination, one finds little analysis that warrants any deference.
In the case it characterized as one of “first impression” on this issue, the commission declared that “[ajdjudicatory bodies, including this Commission, have consistently held that the zone of interest in discrimination cases includes an individual’s association with a member of a protected class.” Dittbenner v. Hapco Auto Parts, Inc., 11 Mass. Discrimination L. Rep. 1139, 1140 (1989) (Dittbenner). But the cases it relied on to support this proposition each involved discrimination on the basis of race, religion, or gender, not handicap. There is no suggestion from the commission’s opinion in Dittbenner that the commission considered whether the language of § 4 (16) would bar or limit a claim of associational discrimination, or whether an employer was required reasonably to accommodate an employee who was coping with a family member’s handicap. In the only other handicap employment discrimination case where, following a full hearing, the commission recognized a claim of associational discrimination, the commission merely cited the holding of Dittbenner and then found that the plaintiff had failed to make a prima facie case of associational discrimination. Hamer v. Cambridge Sch. Dep’t, 21 Mass. Discrimination L. Rep. 154, 156 (1999).1
I am persuaded that the plaintiff in this case has stated a claim under § 4 (16) for two reasons, neither of which arises from any deference to the commission’s interpretation of the statute. First, where an employer provides health insurance coverage to an employee’s family, and a family member is handicapped, an employer will attribute the anticipated or actual *41medical expenses arising from such a handicap to the employee, even if the employer recognizes that a family member and not the employee himself is handicapped, because the potential cost to the employer in higher insurance premiums is the same regardless of whether the medical expenses are incurred by the employee or a family member, and those costs would not be borne by the employer if the employee were terminated from employment. As a result, at least with respect to an employer’s concern with the cost of health insurance premiums, an employee may be regarded by an employer as if he had his family member’s impairment, which places the employee in a position akin to that of an employee who is “being regarded as having [a physical or mental impairment which substantially limits one or more major life activities of a person],” the third alternative definition of “handicap” under G. L. c. 151B, § 1 (17). In such a case, the employer has taken an adverse employment action against the employee because of the fear that the employee’s continued employment will increase the health insurance premiums that must be paid by the employer.
Second, as the court notes, we have looked for guidance in interpreting the handicap discrimination provisions of c. 151B to interpretations by the Federal courts of portions of the Rehabilitation Act of 1973, notably its definition of “disability” currently codified at 29 U.S.C. § 705(9) (2006 & Supp. V 2011) (Rehabilitation Act). We have done so because the Legislature itself “explicitly patterned the definition of ‘handicap’ ” in c. 15IB on the definition of “disability” in the Rehabilitation Act. Dahill v. Police Dep’t of Boston, 434 Mass. 233, 238 & n.8 (2001). See Cox v. New England Tel. & Tel. Co., 414 Mass. 375, 382 (1993) (“we may look” to case law construing Rehabilitation Act for guidance in construing c. 151B). As with G. L. c. 151B, § 4 (16), the language of the Rehabilitation Act suggests that the only persons who are protected by its prohibition against discrimination are those who are themselves disabled. See 29 U.S.C. § 794(a) (2006) (“No otherwise qualified individual with a disability . . . shall, solely by reason of her or his disability, ... be subjected to discrimination under any program or activity receiving Federal financial assistance” [emphasis added]). Yet, as the court notes in this case, numer*42ous Federal courts have interpreted that statute to reach associational handicap discrimination under certain circumstances. See ante at 35-36.
While I agree with the court that the plaintiff has made a cognizable claim of associational discrimination under § 4 (16) in the circumstances he has alleged in this case, I note the special nature of these circumstances. The court’s finding of a cognizable claim here is based solely on the allegation that he was fired because the employer feared the medical expenses his spouse was likely to incur because of her handicap; it is not based on any allegation that he was fired because the employer refused to accommodate his need to devote greater time to family matters because of his wife’s handicap. In fact, the court’s opinion does not suggest that an employer is required under § 4 (16) to provide reasonable accommodation to an employee who is not himself handicapped to allow the employee to attend to important family matters, medical or otherwise. See ante at note 18. Some accommodation may be required by other statutes, see, e.g., Family and Medical Leave Act, Pub. L. 103-3, 103d Cong., 1st Sess., 107 Stat. 6 (1993), codified at 29 U.S.C. §§ 2601 et seq. (2006 & Supp. IV 2010), or by common decency, but the failure to do so is not handicap discrimination under § 4 (16).
I note that § 102(b)(4) of the Americans with Disabilities Act, Pub. L. 101-336, 101st Cong., 2d Sess., 104 Stat. 327 (1990), codified at 42 U.S.C. § 12112(b)(4) (2006 & Supp. V 2011) (ADA), expressly prohibits associational discrimination by defining “discriminate” to include “excluding or otherwise denying equal jobs or benefits to a qualified individual because of the known disability of an individual with whom the qualified individual is known to have a relationship or association.” See Den Hartog v. Wasatch Academy, 129 F.3d 1076, 1082 (10th Cir. 1997) (Den Hartog). But Federal courts, based on the plain language of this provision, its legislative history, and the “interpretive guidance” of the Equal Employment Opportunity Commission, have concluded that an employer is not required under the ADA to provide an employee with reasonable accommodation because of a relative’s or associate’s disability. See Larimer v. International Bus. Machs. Corp., 370 F.3d 698, 700 (7th Cir.), cert. denied, 543 U.S. 984 (2004) (Larimer); Den *43Hartog, supra at 1084-1085; Tyndall v. National Educ. Ctrs., Inc. of Cal., 31 F.3d 209, 214 (4th Cir. 1994). See also 29 C.F.R. Part 1630 App., at 401 (2012) (“employer need not provide the applicant or employee without a disability with a reasonable accommodation because that duty only applies to qualified applicants or employees with disabilities. Thus, for example, an employee would not be entitled to a modified work schedule as an accommodation to enable the employee to care for a spouse with a disability”).2
Because an individual associated with a handicapped person is not entitled to reasonable accommodation under the ADA, the types of cases that fall within the intended scope of the ADA’s “rarely litigated . . . association section” are sharply limited. Larimer, supra. One type of case, as here, is where a “spouse has a disability that is costly to the employer because the spouse is covered by the company’s health plan.” Id. Another type is characterized as “disability by association,” where an employer fears that a presently nondisabled employee will become disabled because of his association with a disabled person, such as through contact with a person carrying the human immunodeficiency virus (HIV), or because of common genetic components, such as where a relative suffers from a genetically caused disease. Id.
The court does not decide in this case whether associational handicap discrimination under G. L. c. 151B, § 4(16), will be interpreted to extend beyond the type of case at issue here. But, where G. L. c. 151B does not expressly identify associational discrimination based on handicap as a form of unlawful employment discrimination, we should be reluctant to interpret it to be more expansive than the ADA, which expressly provides that “excluding or otherwise denying equal jobs or benefits to a *44qualified individual because of the known disability of an individual with whom the qualified individual is known to have a relationship or association” constitutes “discriminat[ion] against a qualified individual on the basis of disability.” 42 U.S.C. § 12112(b)(4) (2006 & Supp. V 2011).
I acknowledge that the Massachusetts Commission Against Discrimination (commission) has recognized claims of associational handicap discrimination in at least three other cases, but each of these cases involved discrimination outside the context of employment, and therefore has limited interpretive relevance in construing G. L. c. 151B, § 4 (16). See Snelders v. Boston Hous. Auth., 23 Mass. Discrimination L. Rep. 339 (2001) (housing); Murphy v. Kenmore Cafe, 17 Mass. Discrimination L. Rep. 1451 (1995) (place of public accommodation, in violation of G. L. c. 272, § 98); Lowe v. Frank’s Place, 16 Mass. Discrimination L. Rep. 1478 (1994) (same).
It is also worthy of note that, under the Americans with Disabilities Act (ADA), a person who is not disabled but is nonetheless protected from discrimination because he is “regarded as” disabled is not entitled to reasonable accommodation. See 42 U.S.C. § 12201(h) (Supp. V 2011) (employers and other covered entities “need not provide a reasonable accommodation or a reasonable modification to policies, practices, or procedures to an individual who meets the definition of disability in section 12102[1] of this title solely under subparagraph [C] of such section,” which provides that an individual is considered disabled if he is “being regarded as having such an impairment”); 29 C.F.R. Part 1630 App., at 393 (2012).